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Students get through the TN Board 12th Bio Zoology Important Questions Chapter 6 Evolution which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 6 Evolution

Very short answer questions

Question 1.
Explain briefly the theory of special creation.
Answer:
The theory of special creation is the process of origin of life in which all the components of the universe namely plants and animals are created by a supernatural power, referred to as God.

Question 2.
Define biogenesis.
Answer:
Biogenesis is defined as a process, through which life arose from pre-existing life. Hendry Bastian coined this word “biogenesis”.

Question 3.
Explain the view of oparin-Haldane on the origin of life.
Answer:
Oparin and Haldane independently proposed prebiotic soup with a wide range of organic compounds formed with energy as lightning or UV light, leading to the origin of life.

Question 4.
Mention any two eras of earth’s history.
Answer:

1. Paleozoic era
2. Mesozoic era

Question 5.
Give an example for analogous structures.
Answer:
An example of an analogous structure is the wings of birds and insects, which are different in structure but do the same function of flight.

Question 6.
Name any two scientists, who proposed Neo-Lamarckism.
Answer:

1. Osborn
2. Packard

Question 7.
Define mutation theory of evolution.
Answer:
Mutation theory is defined as a process of sudden and large variations due to mutation which is responsible for the origin of new species. This is proposed by Hugo De Vries.

Question 8.
Defined artificial selection.
Answer:
Artificial selection is defined as a process in which human exploitation of forests, oceans, and fisheries or the use of pesticides, herbicides, or drugs can occur.

Question 9.
Give examples for adaptive radiation.
Answer:

1. Darwin’s finches
2. Marsupials in Australia

Question 10.
Define Microevolution.
Answer:
Microevolution is a process that refers to the changes in allelic frequencies within a population.

Question 11.
What is the Sewall Wright effect?
Answer:
Sewall Wright’s effect is otherwise known as genetic drift and is a mechanism of evolution, in which allelic frequencies of a population change over a generation due to chance.

Question 12.
State Hardy-Weinberg law.
Answer:
The law states that if the population is in an equilibrium state, the frequencies of alleles and genotypes or sets of alleles in a population will remain the same over generations.

Question 13.
Name the earliest fossils of pre-historic man.
Answer:

1. Ramapithecus
2. Sivapithecus

Question 14.
Explain the characteristics of Homo erectus.
Answer:

1. They are the first human-like being to live in around 1.7 mya.
2. The skull was flatter and thicker than the modem man.
3. They had a large brain capacity of around 900 ccs.
4. They ate meat.

Short answer questions

Question 1.
Explain briefly about the Mesozoic era:
Answer:
The Mesozoic era is otherwise known as the golden age of reptiles. This era is divided into three periods as follows:

1. Triassic: Origin of egg-laying mammals.
2. Jurassic: Dinosaurs were dominant and the fossil bird -Archaeopteryx was present on earth.
3. Cretaceous: Extinction of toothed birds and dinosaurs, the emergence of modem birds occur.

Question 2.
Distinguish between Homologous structures and Analogous structures.
Answer:

Question 3.
Explain the principles of Lamarck’s theory.
Answer:
Lamarck’s proposed two principles in his theory and they are:

1. The theory of use and disuse: The organs increase in size when they are used often and the organs, that are not used will degenerate.
   Eg: The neck in the giraffe is an example of constant use and the absence of limbs in snakes is an example of disuse theory.
2. The theory of inheritance of acquired characters:
   The characters developed by an organism during its lifetime are the acquired characters. Lamarck postulated that these acquired characters are then inherited to the next generation.

Question 4.
List the three ways of the struggle for existence denoted by Darwin.
Answer:

1. The intraspecific struggle between individuals of the same species for food, space, and mate.
2. The interspecific struggle between different species for food and space.
3. Struggle with the environment to cope with climatic variations like floods, earthquakes, drought, etc.

Question 5.
Write down the salient features of mutation theory.
Answer:

1. Mutations or discontinuous variations are inherited from other generations.
2. Mutations occur from time to time in naturally breeding populations.
3. No intermediate forms occur, as they are fully-fledged.
4. They are strictly subjected to natural selection.

Question 6.
What is gene flow? Explain it briefly.
Answer:
Gene flow is referred to as the movement of genes through gametes or movement of individual organisms in and out of a population. Immigration in which the gametes and the organisms enter the population may have new alleles or may bring in existing alleles. These existing alleles in different proportions due to incoming alleles may alter the allelic frequency of the original population. Therefore gene flow can act as a strong agent of evolution.

Question 7.
Distinguish between Homo habilis and Homo erectus.
Answer:

Long answer questions

Question 1.
Give an account of the theory of chemical evolution.
Answer:
The theory of chemical evolution states that the primitive organisms is the primordial environment of earth evolved spontaneously from inorganic substances and physical forces like lightning, UV radiation volcanic activities, etc., This leads to the formation of organic compounds from methane, ammonia, hydrogen, and water.
According to Oparin (1924), these organic compounds could have undergone a series of reactions, leading to the formation of more complex molecules. These complex molecules formed colloidal aggregates or coacervates, which are able to absorb and assimilate organic compounds from the aquatic environment, leading to the origin of life.
According to Haldane, the primordial sea served as a vast chemical laboratory powered by solar energy. The UV radiation gave rise to organic compounds from CO₂ and NH₃. Organic monomers and polymers were produced in the sea. These monomers and polymers acquired lipid membranes and transformed into the first living cells. This is termed as a prebiotic soup by Haldane and this leads to the origin of life as Oparin-Haldane views.

Question 2.
Give the diagrammatic representation of Urey-Miller’s experiment an origin of life.
Answer:

Question 3.
Explain ‘Biogenetic law’ proposed by Ernst von Haeckel.
Answer:
Biogenetic law states that the higher animals pass through stages of lower animals during their embryonic development. This law is otherwise known as the theory of recapitulation, which states that ontogeny repeats or recapitulates phylogeny. Ontogeny is the life history of an organism and phylogeny is the evolutionary history of a race. According to this law, the embryonic stages of a higher animal resemble its ancestors. For example, pharyngeal gill slits, yolk sac, the appearance of the tail in the human embryo.
This indicates that the human embryo repeats the embryonic history and not the adult history of the organisms. Therefore, the biogenetic law is not universal. It is now thought that animals do not recapitulate the adult stage of any ancestors.

Question 4.
Explain the basic factors involved in the process of organic evolution.
Answer:

1. Gene mutation: This refers to the changes in the structure of the gene. The phenotypes of an organism will be altered due to gene mutation and produce variations in the offspring.
2. Chromosomal mutation: This refers to the changes in the structure of the chromosomes due to deletion, addition, duplication, inversion, or translocation.
   These changes in the structure of chromosomes bring about phenotypic variations in an organism, which in turn brings variation in their offsprings.
3. Genetic recombination: This is a phenomenon due to the crossing over of genes during meiosis. This brings about the heritable genetic variation of an organism and its offspring.
4. Natural selection: This does not favor any genetic variation. When such variations occur, it favours some genetic changes, rejecting others (driving force of evolution).
5. Reproductive isolation: This helps in preventing inbreeding between related species.

Choose the correct answers.

1. Match the following:


(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

2. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(c) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)

3. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)

4. Match the following:

(a) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(a) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)

5. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)

6. Neo Darwinism is proposed by:
(a) De Vries
(b) Weisman
(c) James Crick
(d) Osborn
Answer:
(b) Weisman

7. Hardy-Weinberg law refers to:
(a) Gene frequency in an individual
(b) Gene flow in an organism
(c) Gene frequency within a population
(d) DNA sequence of an organism.
Answer:
(c) Gene frequency within a population

8. The typical example for adaptive radiation is:
(a) Industrial melanism
(b) Darwin’s finches
(c) Albinism
(d) Pleotropism
Answer:
(b) Darwin’s finches

9. What is the brain capacity of Homo ability
(a) 450-500 cc
(b) 600-650 cc
(c) 350-450 cc
(d) 650-800 cc
Answer:
(d) 650-800 cc

10. Biogenetic law was first proposed by:
(a) Ernst Von Hackel
(b) Heinrich
(c) Wallace
(d) Watson
Answer:
(a) Ernst Von Hackel

11. Choose the odd man out:
(a) Darwin
(b) Lamarck
(c) Weisman
(d) Watson and Crick
Answer:
(d) Watson and Crick

12. Find out the odd one out:
(a) Natural Selection
(b) Creation
(c) Darwinism
(d) Lamarckism
Answer:
(b) Creation

13. Identify the odd one out:
(a) Silurian
(b) Ordovician
(c) Jurassic
(d) Devonian
Answer:
(c) Jurassic

14. Indicate the odd one out:
(a) Paleozoic era
(b) Cenozoic era
(c) Mesozoic era
(d) Golden era
Answer:
(d) Golden era

15. Choose the odd one out:
(a) Genetic drift
(b) Genome
(c) Mutation
(d) Gene flow
Answer:
(b) Genome

16. Which of the following pair is correct?

Answer:
(b)

17. Choose the incorrect pair:

Answer:
(d)

18. Indicate the correct pair:

Answer:
(b)

19. Choose the incorrect pair:

Answer:
(b)

20. Which of following is the correct pair?

Answer:
(c)

21. Assertion: Living organisms originated from non-living substances through a series of chemical and molecular evolution over millions of years, as stated by Thomas Huxley.
Reason: Oparin suggested that the organic compounds could have undergone a series ‘ of reactions leading to more complex molecules.
(a) Assertion and reason are correct, reason is the correct explanation of assertion.
(b) Assertion and reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is not correct, reason is correct.
(d) Assertion and reason are not correct.
Answer:
(b) Assertion and reason are correct, reason is not the correct explanation of assertion.

22. Assertion: Monera are considered as ancestral to bacteria and blue-green algae
Reason: Monera is the primitive cells that contained clumps of nucleoproteins embedded in the cell membrane.
(a) Assertion and reason are correct, reason is the correct explanation of assertion.
(b) Assertion and reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is not correct, reason is correct.
(d) Assertion and reason are not correct.
Answer:
(a) Assertion and reason are correct, reason is the correct explanation of assertion.

23. Assertion: Fossilization is a process by which plant and animal remains are preserved in sedimentary rocks.
Reason: When marine animals die, their hard parts like bones, shells, etc., are covered with sediments and protected from further deterioration for years.
(a) Assertion and reason are correct, reason is the correct explanation of assertion.
(b) Assertion and reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is not correct, reason is correct.
(d) Assertion and reason are not correct.
Answer:
(a) Assertion and reason are correct, reason is the correct explanation of assertion.

24. Assertion: The basic plan of basic structure such as forelimbs and hind limbs in vertebrates are homologous.
Reason: Forelimbs of vertebrates exhibit similarity with each other and are made up of similar bones such as the humerus, radius, ulna, carpels metacarpals, and phalanges.
(a) Assertion and reason are correct, reason is the correct explanation of assertion.
(b) Assertion and reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is not correct, reason is correct.
(d) Assertion and reason are not correct.
Answer:
(a) Assertion and reason are correct, reason is the correct explanation of assertion.

25. Assertion: Mutations or discontinuous variations are not transmitted to other generations.
Reason: Because they are somatic variations.
(a) Assertion and reason are correct, reason is the correct explanation of assertion.
(b) Assertion and reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is not correct, reason is correct.
(d) Assertion and reason are not correct.
Answer:
(d) Assertion and reason are not correct.

26. Which of the following statement is correct?
(a) In a naturally breeding population, mutations occur once in life.
(b) In a naturally breeding population mutations occur from time to time.
(c) In a naturally breeding population mutations may not occur.
(d) None of the above.
Answer:
(b) In a naturally breeding population mutations occur from time to time.

27. Choose the incorrect statement:
(a) Darwin failed to explain the mechanism variation.
(b) Darwin wrote the book “The origin of species by Natural Selection”.
(c) He focused on variations that are mostly heritable.
(d) He did not distinguish between somatic and germinal variation.
Answer:
(c) He focused on variations that are mostly heritable.

28. Indicate the correct statement:
(a) Cenozoic is the age of reptiles.
(b) Cenozoic era is subdivided into two periods namely tertiary and quaternary.
(c) Cenozoic era is the age of dinosaurs.
(d) None of the above.
Answer:
(b) Cenozoic era is subdivided into two periods namely tertiary and quaternary.

29. Which of the following statement is correct?
(a) In stabilizing selection, the organisms with both extreme phenotypes are eliminated, while organisms with average phenotypes survive.
(b) The organisms with both extreme phenotypes survive, whereas organisms with average phenotypes are eliminated.
(c) This is a rare form of selection leading to population equilibrium.
(d) None of the above.
Answer:
(a) In stabilizing selection, the organisms with both extreme phenotypes are eliminated, while organisms with average phenotypes survive.

30. Choose the incorrect statement:
(a) Ramapithecus were derived from ape-like Dryopithecus.
(b) Australopithecus lived in East African grasslands.
(c) Homo erectus lived in Gangetic valley.
(d) Neanderthal human was found in Germany.
Answer:
(c) Homo erectus lived in Gangetic valley.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 5 Molecular Genetics which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 5 Molecular Genetics

Very short answer questions

Question 1.
Define gene.
Answer:
A gene is defined as a basic physical and functional unit of heredity.

Question 2.
What is the main aim of the Hershey and Chase experiment on T2 bacteriophage?
Answer:
The main objective of the Hershey and Chase experiment on T2 bacteriophage is to prove whether it was DNA or protein that acts as genetic material.

Question 3.
What are the components of a nucleotide?
Answer:
Each nucleotide consists of three components namely nitrogenous base, a pentose sugar, and a phosphate group.

Question 4.
Define genophore.
Answer:
Genophore is defined as the DNA of prokaryotes, which is almost circular and lacks chromatin organization.

Question 5.
Explain histone octamer.
Answer:
In nucleosome, Z molecules of four histone proteins H2A, H2B, H3, and H4 are organized to form a unit of eight molecules called histone octamer.

Question 6.
Name any two enzymes involved in DNA replication.
Answer:

1. DNA Polymerase
2. DNA ligase.

Question 7.
Define Transcription.
Answer:
Transcription is a process through which the copying of genetic information from one strand of DNA into RNA takes place.

Question 8.
What is a promoter unit?
Answer:
The promoter region is located towards the 5 ends. It is a DNA sequence in which RNA polymerase binds.

Question 9.
Define genetic code.
Answer:
The genetic code is the sequence relationship nucleotide in genes (or mRNA) and the amino acids in a protein, they encode.

Question 10.
Define ‘Non-sense’ codon.
Answer:
‘Non-sense’ codons are defined as the codons designated as termination (stop) codons.

Question 11.
Define translation.
Answer:
The translation is a process in which the polymerization of amino acids to form a polypeptide chain takes place.

Question 12.
What is meant by reading frame?
Answer:
A reading frame is a codon that is formed by dividing up a sequence of bases in DNA or RNA.

Question 13.
Define operon.
Answer:
Operon is defined as a cluster of genes with related functions.

Question 14.
Mention any two enzymes involved in the metabolism of lactose in E.Coli.
Answer:

1. p – galactosidase
2. Transacetylase

Question 15.
What is pharmacogenomics?
Answer:
Pharmacogenomics is the study of genes, affecting a person’s response to drugs.

Short answer questions

Question 1.
Distinguish between one gene-one enzyme hypothesis and one gene-one polypeptide hypothesis.
Answer:

Question 2.
Mention any three properties of Mendelian rules of inheritance.
Answer:

1. Genes are arranged in a single linear order on chromosomes.
2. A specific position called a locus, where the genes occupy the chromosome.
3. Gene may exist in several alternate forms called alleles.

Question 3.
Distinguish between Nucleoside and nucleotide.
Answer:

Question 4.
Differentiate DNA and RNA based on nitrogenous bases.
Answer:

1. DNA and RNA both have four bases (two purines and two pyrimidines)
2. Adenine (A) and Guanine (G) are the purines.
3. Cytosine (C), Thymine (T), and uracil (U) are the pyrimidines.
4. In DNA molecule, Adenine (A), Guanine (G), Thymine (T), and Cytosine are present.
5. In RNA molecule, instead of Thymine (T), Uracil (U) is present.
6. Therefore, the nitrogenous base Thymine is unique for DNA, while uracil is unique for RNA.

Question 5.
Differentiate monocistronic mRNA from polycistronic mRNA.
Answer:

Question 6.
Distinguish between promoters and operators.
Answer:

Question 7.
What are genes present in lac operon? Mention their function.
Answer:
The genes present in lac operon and their function include the following:

1. One inhibitor gene (i) present is between promoter site (p) and operator site (o).
2. Three structural genes namely lac z, y, and lac a gene are present.
3. lac 2 gene codes for B galactosidase enzyme.
4. lac y gene codes for permease enzyme.
5. lac gene codes for transacylase enzyme.

Question 8.
Explain negative control of transcription initiation.
Answer:

1. The repressor protein binds to the operator of the operon, preventing RNA polymerase from transcribing the operon.
2. When an inducer such as lactose is present, the repressor protein is inactivated by the interaction with the inducer.
3. This allows RNA polymerase to bind to the promoter site and transcribe the operon to produce lac mRNA.
4. This enables the formation of all required enzymes for lactate metabolism.

Long answer questions

Question 1.
Mention any five salient features of the human genome project.
Answer:

1. The encoded proteins are only 5% even though more than 3 billion nucleotide bases are present in the human genome.
2. The largest human gene is dystrophic with 2.4 million bases.
3. The transposable elements such as LINE and ALU sequence form about 50% of the functional genome in human beings.
4. chromosome 19 has the highest gene density, while chromosome 13 and y chromosomes have the lowest gene densities.
5. Chromosome 1 has 2968 genes while the ‘Y’ chromosome has only 231 genes.

Question 2.
Explain the wobble hypothesis with an example.
Answer:
Crick in 1966 proposed this hypothesis, which states:

1. tRNA anticodon has the ability to wobble at its 5′ and by pairing with even non-complementary base of mRNA codon.
2. In anticodon pairing, the third base may not be complementary.
3. The third base of the codon is called wobble base and the position is known as wobble position.
4. At the first two positions, actual base pairing occurs.
5. According to this hypothesis, it reduces the number of tRNAs required for the synthesis of the polypeptide.
6. It also overcomes the effect of code degeneracy.
   Eg:
   
   In this example, the codons and anticodons do not match perfectly.
   Yet, the required amino acid is produced perfectly. This helps the economy of tRNA – GUU, GUC, GUA, and GUG code for valine amino acid.

Question 3.
Give the diagrammatic representation of semi conservation mode of DNA replication based on Meselson and Stahl experiments.
Answer:

Question 4.
Draw the schematic representation of the lac operon model.
Answer:

Question 5.
List out any five applications of the human genome project.
Answer:

1. Mapping the human genome provides information on DNA sequence, which makes it possible to identify genetic abnormalities.
2. This helps to diagnose diseases and to provide counseling to those planning to have children. (Hi) This kind of information provides clues to understand human biology and learning non¬human organisms for comparison.
3. This helps to create possibilities for new gene therapies.
4. Another important advantage of this kind of information is that it provides a new era of molecular medicine characterized by looking into the most fundamental causes of diseases than treating the symptoms.

Question 6.
Give the sequential steps involved in DNA fingerprinting.
Answer:

Choose the correct answers.

1. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(b) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)

2. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(iii); (q)-(i); (r)-(iv); (s)-(ii)
Answer:
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

3. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)

4. Match the following:


(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(iii); (r)-(iv); (s)-(i)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

5. Gene is the functional unit of:
(a) Inheritance
(b) Human genome
(c) Human history
(d) DNA
Answer:
(a) Inheritance

6. Several biochemical reactions are catalyzed by RNA and such RNA is known as:
(a) Ribosome
(b) RNA ase
(c) Ribozyme
(d) RNA Hydrogenase
Answer:
(c) Ribozyme

7. The functional phosphate group (PO4) gives DNA and RNA the property of acid by releasing:
(a) a neutron in solution
(b) H+ ion in solution
(c) OH- ion in solution
(d) an electron in solution
Answer:
(b) H+ ion in solution

8. International human genome project was launched in the year:
(a) 1969
(b) 1978
(c) 1992
(d) 1990
Answer:
(d) 1990

9. Choose the odd man out:
(a) P-Galactosidase
(b) Permease
(c) DNA polymerase
(d) Transacetylase
Answer:
(c) DNA polymerase

10. Find out the odd one:
(a) Replication
(b) Transcription
(c) Translation
(d) Termination
Answer:
(a) Replication

11. Indicate the odd one:
(a) Adenine
(b) Guanine
(c) Uracil
(d) Thymine
Answer:
(c) Uracil

12. Choose the odd man out:
(a) Rosalind Franklin
(b) Janies Watson
(c) Maurice Wilkins
(d) Walter Gilbert
Answer:
(d) Walter Gilbert

13. Choose the correct pair:

Answer:
(b)

14. Which of the following pair is incorrect?

Answer:
(c)

15. Choose the correct pair:

Answer:
(a)

16. Indicate the incorrect pair:

Answer:
(d)

17. Assertion: In the lac operon, a polycistronic structural gene is regulated by a common promoter and regulator.
Reason: It is an example of negative control of transcription initiation.
(a) Both Assertion and Reason are true, the reason is the correct explanation of the assertion.
(b) Both Assertion and Reason are true, Reason is not the correct explanation of assertion.
(c) Assertion is true, Reason is false.
(d) Both Assertion and Reason are false.
Answer:
(b) Both Assertion and Reason are true, Reason is not the correct explanation of assertion.

18. Assertion: Hershey and chase in their experiments, allowed the phages to infect bacteria in a culture medium which contains the radioactive isotopes 35S or 35P.
Reason: The bacteriophage that grew in the presence of 35S had labeled proteins and bacteriophages grown in presence of 82P had labeled DNA.
(a) Both Assertion and Reason are true, reason is the correct explanation of assertion.
(b) Both Assertion and Reason are true. The reason is not the correct explanation of assertion.
(c) Assertion is true, Reason is false.
(d) Both Assertion and Reason are false.
Answer:
(a) Both Assertion and Reason are true, reason is the correct explanation of assertion.

19. Assertion: The bases of nitrogen-containing molecules having the chemical properties of a base are the nitrogenous bases of DNA. Reason: Because they release H+ ions or protons in solution.
(a) Both Assertion and Reason are true, reason is the correct explanation of assertion.
(b) Both Assertion and Reason are true, Reason is not the correct explanation of assertion.
(c) Assertion is true, Reason is false.
(d) Both Assertion and Reason are false.
Answer:
(c) Assertion is true, Reason is false.

20. Assertion: The mode of DNA replication was first demonstrated in 1956 by Meselson and stahl.
Reason: They designed an experiment to distinguish between DNA and protein as genetic material.
(a) Both Assertion and Reason are true, the reason is the correct explanation of the assertion.
(b) Both Assertion and Reason are true, Reason is not the correct explanation of assertion.
(c) Assertion is true, Reason is false.
(d) Both Assertion and Reason are false.
Answer:
(d) Both Assertion and Reason are false.

21. Which of the following statement is true?
(a) Watson and Crick proposed a semi-conservative replication hypothesis.
(b) Watson and Crick proposed a conservative replication hypothesis.
(c) Watson and Crick proposed imperative replication hypothesis.
(d) None of the above.
Answer:
(a) Watson and Crick proposed semi conservative replication hypothesis.

22. Indicate the incorrect statement:
(a) A transcriptional unit in DNA is defined by three regions namely a promoter, a structural gene and a terminator.
(b) The promoter is located at the 3′ end.
(c) The presence of promoter in a transcription unit defines the template and coding “strands.
(d) Besides promoter Eukaryotes need an enhancer for transcription.
Answer:
(b) The promoter is located at the 3′ end.

23. Choose the correct statement:
(a) The genetic codon is a quadruplicate code.
(b) The genetic code is not universal.
(c) The genetic code is a triplet code.
(d) In Non-ambiguous code, more than one codon is needed for one amino acid.
Answer:
(c) The genetic code is a triplet code.

24. Which of the following statement is not correct?
(a) Human genome contains 3 billion nucleotide bases.
(b) Average human gene consists of 3000 bases.
(c) In humans, chromosome 19 has the highest gene density.
(d) All the above statements are not correct.
Answer:
(d) All the above statements are not correct.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 4 Principles of Inheritance and Variation which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 4 Principles of Inheritance and Variation

Very short answer questions

Question 1.
Define Heredity.
Answer:
Heredity is defined as a process through which the inheritance of characters from parent to offspring.

Question 2.
Explain multiple alleles.
Answer:
Multiple alleles of a gene is that a particular trait is controlled by three or more alleles of a gene on the homologous chromosome of an organism.

Question 3.
What is Fischer and Race hypothesis?
Answer:
Fischer and Race hypothesis says that the Rh factor involves three different pairs of alleles, which are located on three different closely linked loci on the chromosome pair.

Question 4.
Heterogametic males- Explain.
Answer:
In this method of sex determination, the males are heterogametic, producing two types of gametes, while female is homogametic, producing similar gametes.

Question 5.
What are holandric genes?
Answer:
Holandric genes are the genes present in Y chromosomes. These genes have no corresponding allele in X chromosomes.

Question 6.
What is Karyotyping?
Answer:
Karyotyping is a technique through which a completed set of chromosomes is separated from a cell and arrange in pairs.

Question 7.
Define ideogram.
Answer:
Ideogram is the technique of diagrammatic representation of chromosomes.

Question 8.
What is meant by pedigree?
Answer:
Pedigree is a family tree, showing the inheritance path way for the specific phenotypic character, using the standard genetic symbol.

Question 9.
What is a genetic disorder?
Answer:
A genetic disorder is a disease or syndrome caused by chromosomal abnormality or change in an individual DNA.

Question 10.
What is Huntington’s chorea?
Answer:
Huntington’s chorea is a genetic disorder due to an autosomal dominant lethal gene in man. The symptoms are involuntary jerking of the body and progressive degeneration of the nervous system. Patients with this disease usually die between the age of 35 and 40.

Short answer questions

Question 1.
What is the Wiener hypothesis? Explain it briefly.
Answer:
The Wiener hypothesis is proposed by Wiener and it states that at a single Rh locus, there are eight alleles (R¹, R², R⁰, R², r, r¹, r¹¹, r^y. The Rh-positive will be produced, when all genotypes carry a dominant ‘R’ allele (R¹, R², R⁰, R²), whereas the Rh-negative phenotype is expressed due to double recessive gentypes (rr, rr¹, rr¹¹, rr^y).

Question 2.
Explain the prevention method of Erythroblastosis foetalis.
Answer:
One of the preventive methods of Erythroblastosis foetalis is to administrate anti D antibodies to the mother at the 28th and 34th week of gestation as a prophylactic measure. This anti D antibody should be given to Rh^– mother immediately after childbirth if she delivers Rh⁺ child. This will destroy Rh^– foetal RBCs by developing passive immunity and preventing the formation of anti D antibodies in the mother’s blood; before the sensitization of the mother’s immune system.

Question 3.
What is colour blindness? Explain it briefly.
Answer:
The colour blindness is a sex-linked character in human being, who is unable to distinguish red and green colour. This allele is present in X chromosomes. The recessive form of this allele cannot produce colour sensitive cone cells. Therefore homozygous female of genotype X^cX^c and hemizygous X^cY males cannot differentiate between red and green colour. This phenomenon is called colour blindness.

Question 4.
Give the diagrammatic representation of the human karyotype.
Answer:

Question 5.
How does the disorder phenylketonuria occur?
Answer:
Phenylketonuria is due to the error of phenylalanine metabolism. It is an inborn disorder due to the mutation of the gene PAH (phenylalanine hydroxylase gene), which controls the production of the hepatic enzyme called phenylalanine hydroxylase. This enzyme is responsible for the conversion of phenylalanine to tyrosine. Phenylalanine accumulates and gets converted into phenyl pyruvic acid and other derivatives in disease affected individuals who lacks phenylalanine dehydroxylase enzyme. This results in the excretion of phenylpyruvic acid through urine. The symptoms of this disorder include severe mental retardation and light pigmentation of skin and hair.

Question 6.
What are the symptoms of Patau’s syndrome?
Answer:
The symptoms of Patau’s syndrome include multiple and severe body malformation along with profound mental deficiency. The other symptoms are having a small head with small eyes, cleft palate, defective information of the brain and internal organs.

Long answer questions

Question 1.
Write an account of ABO blood groups in human being.
Answer:
Four types of blood groups are noticed in human being namely A, B, AB and O groups. These groups differ from person to person, as they are different on the basis of the presence of antigens on the membrane of RBC and epithelial cells. The antigen ‘A’ and ‘B’ on the surface of RBCs of human blood were discovered by Karl Landsteiner. Three kinds of blood groups were recognized based on these antigens. The blood group A individuals have A antigen, while individuals having B blood group have ‘B’ antigen. The individuals with A and B antigens are grouped under AB blood group, which is a rare group. The individuals having O blood group do not have antigen and this group is known as a universal donor. When two incompatible blood groups are mixed agglutination of erythrocytes (RBCs) occurs.

Question 2.
Explain the disorder of Erythroblastosis foetalis.
Answer:
Erythroblastosis foetalis is caused by the Rh factor incompatibility in childbirth. If an Rh-negative woman carries an Rh-positive man, the foetus may be Rh-positive inherited from its father. The mother having Rh-positive foetus in her womb becomes immune logically sensitized. The mother’s blood recognizes the Rh antigen, due to damages of blood vessels during childbirth. This causes the sensitized mother to produce Rh antibodies. This IgG type of antibodies are small molecule and can cross the placenta and enter the foetal circulation. The child is delivered before these processes of anti ‘D’ antibody production by the sensitized mother. Hence there is no effect associated with the exposure of the mother to Rh-positive antigen during first childbirth. But in subsequent pregnancy by the same mother, the child is exposed to antibodies produced by the mother against Rh antigen, which is carried across the placenta into foetal circulation that causes haemolysis of foetal RBCs. This results in anaemia or haemolytic jaundice, which is called Erythroblastosis foetalis or Haemolytic disease of new born (HDN).

Question 3.
Describe the Lygaeus type of sex determination in Drosophila.
Answer:
The Lygaeus type of sex determination is otherwise called XX-XY type, commonly found in Drosophila and human being. In Drosophila, the females are homogametic with XX chromosomes and produce only one type of gamete with X chromosome while the males are heterogametic with XY chromosomes and produce two types of gametes, one with one X chromosome and the other with a Y chromosome. The sex of the progeny depends on the fertilizing sperm. An egg, which is fertilized by a sperm with an X chromosome will develop into a female, while an egg, which is fertilized with a sperm having a Y chromosome will develop into a male.

Question 4.
Explain the inheritance of colour blindness in a marriage of a colour blind woman with a normal man.
Answer:
When a colour blind woman with two recessive genes (X^cX^c) marries a normal man (X⁺Y) among the progenies, all the sons are colour blind and all the daughters are normal, but carriers this gene in F₁ generation.
If marriage between this F₁ female with a colour blind man takes place among progenies, normal visioned carrier daughters and colour blind daughters and males of colour blindness and normal vision will be expected in the F₂ generation.

Question 5.
Differentiate Down’s syndrome from Turner’s syndrome.
Answer:

Multiple choice questions

1. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iv)
Answer:
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

2. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(c) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(c) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)

3. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)

4. Match the following:

(a) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
Answer:
(a) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

5. The unit of heredity is known as:
(a) Chromosome
(b) Nucleus
(c) Gene
(d) RNA
Answer:
(c) Gene

6. The inheritance of different blood groups in human being is determined by:
(a) 3 autosomal alleles
(b) 3 sex linked alleles
(c) 4 autosomal alleles
(d) 4 Sex linked alleles
Answer:
(a) 3 autosomal alleles

7. What is the causative factor for Erythroblastosis foetails?
(a) Bacteria
(b) Virus
(c) Rh- factor
(d) Phenylalanine
Answer:
(c) Rh- factor

8. The method of sex determination in honey bee is:
(a) XX-XY type
(b) Haplodiploidy
(c) ZW-ZZ type
(d) Heterochromatic
Answer:
(b) Haplodiploidy

9. Y-chromosome linked character in human being includes:
(a) Phenylketonuria
(b) Colour blindness
(c) Albinism
(d) Hypertrichosis
Answer:
(d) Hypertrichosis

10. Choose the odd one out (sex-determination):
(a) Honey bee
(b) Drosophila
(c) Human being
(d) Monkey
Answer:
(a) Honey bee

11. Find out the odd one:
(a) Thalassemia
(b) Phenylketonuria
(c) Hypertrichosis
(d) Albinism
Answer:
(c) Hypertrichosis

12. Indicate the odd one:
(a) Blood group A
(b) Blood group B
(c) Rh positive
(d) Blood group AB
Answer:
(c) Rh positive

13. Choose the odd one out:
(a) Chromosome mapping
(b) Recombination frequency
(c) Linkage of genes
(d) Karyotyping
Answer:
(d) Karyotyping

14. Which of the following is the correct pair?

Answer:
(b)

15. Find out the incorrect pair:

Answer:
(c)

16. Indicate the correct pair:

Answer:
(a)

17. Choose the correct pair:

Answer:
(b)

18. Assertion: Blood group O is called a universal donor.
Reason: Because no agglutination antigen is present in ‘O’ blood group.
(a) Assertion and Reason are correct, reason is the correct explanation of assertion.
(b) Assertion and Reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is incorrect, Reason is correct.
(d) Both assertion and Reason are not correct.
Answer:
(a) Assertion and Reason are correct, reason is the correct explanation of assertion.

19. Assertion: An individual having D antigen are Rh-positive (Rh⁺).
Reason: Rhesus factor in the blood is inherited as a dominant trait.
(a) Assertion and Reason are correct, reason is the correct explanation of assertion.
(b) Assertion and Reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is incorrect, Reason is correct.
(d) Both assertion and Reason are not correct.
Answer:
(b) Assertion and Reason are correct, reason is not the correct explanation of assertion.

20. Assertion: The sex determination is a honey bee is of XX-XO type.
Reason: There is no Y chromosome in a male.
(a) Assertion and Reason are correct, reason is the correct explanation of assertion.
(b) Assertion and Reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is incorrect, Reason is correct.
(d) Both assertion and Reason are not correct.
Answer:
(d) Both assertion and Reason are not correct.

21. Assertion: Thalassemia is an autosomal recessive gene disorder.
Reason: Thalassemia is controlled by two closely linked genes on chromosome 16.
(a) Assertion and Reason are correct, reason is the correct explanation of assertion.
(b) Assertion and Reason are correct, Reason is not the correct explanation of assertion.
(c) Assertion is incorrect, Reason is correct.
(d) Both Assertion and Reason are not correct.
Answer:
(b) Assertion and Reason are correct, Reason is not the correct explanation of assertion.

22. Assertion: Trisomic condition of chromosome 13 results in Down’s syndrome.
Reason: It is characterized by severe mental retardation.
(a) Assertion and Reason are correct, reason is the correct explanation of assertion.
(b) Assertion and Reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is incorrect, Reason is correct.
(d) Both assertion and Reason are not correct.
Answer:
(c) Assertion is incorrect, Reason is correct.

23. Which of the following statement is correct?
(a) A gene can mutate several times producing several alternative forms.
(b) A gene can mutate only once and alter the character once.
(c) A gene can mutate reversely once in a lifetime.
(d) A gene can mutate thrice in a lifetime.
Answer:
(a) A gene can mutate several times producing several alternative forms.

24. Choose the incorrect statement:
(a) In the homogametic female system of sex determination, the males produce two types of gametes.
(b) In the homogametic female system of sex determination, females produce only one type of gamete.
(c) In the female heterogametic type, the females produce only one type of gametes.
(d) None of the above.
Answer:
(c) In the female heterogametic type, the females produce only one type of gametes.

25. Indicate the correct statement:
(a) Kin selection is normally seen in moth.
(b) Kin selection is normally seen in honey bees.
(c) Kin selection is normally seen in butterflies.
(d) None of the above.
Answer:
(b) Kin selection is normally seen in honey bees.

26. Which of the following statement is correct?
(a) Haemophilia is commonly known as bleeder’s disease.
(b) This disease was first discovered by John Cotto in 1803.
(c) This disease is more common in female than male human.
(d) This is caused by a sex-linked gene.
Answer:
(c) This disease is more common in female than male human.

27. Choose the correct statement:
(a) Turner’s syndrome is caused by a trisomic condition.
(b) Turner’s syndrome is due to the loss of an X chromosome in female.
(c) Turner’s syndrome is due to the presence of an additional copy of the X chromosome.
(d) None of the above.
Answer:
(b) Turner’s syndrome is due to the loss of an X chromosome in female.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 3 Reproductive Health which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 3 Reproductive Health

Very short answer questions

Question 1.
What is amniocentesis?
Answer:
Amniocentesis is a technique used to find out any chromosomal abnormalities in the foetus.

Question 2.
Expand the abbreviation POCSO and PCPNDT.
Answer:

1. POCSO – Prevention of Children from Sexual Offences.
2. PCPNDT – Preconception and Prenatal Diagnostic Technique.

Question 3.
Define Birth control.
Answer:
Birth control is the voluntary use of contraceptive methods to prevent childbirth, by preventing fertilization of egg or by preventing the implantation of the embryo in the uterus.

Question 4.
What is the natural contraceptive method?
Answer:
The natural contraceptive method is the procedure to prevent the meeting of sperm with ovum in order to prevent fertilization.

Question 5.
Mention any two chemical barriers used in the contraceptive methods.
Answer:

1. Foaming tablets
2. Melting suppositories

Question 6.
Explain briefly the hormonal barrier in the contraceptive devices.
Answer:
The hormonal barrier is a contraceptive method, in which the hormonal imbalance prevents the ovaries from releasing ova and thickens the cervical fluid. This keeps the sperm away from the ovum.

Question 7.
What are Non-medicated IUDS?
Answer:
Non-medicated IUDs are intrauterine devices made of plastic or stainless steel.
Eg: the Lippes loop is a double S-Shaped plastic device.

Question 8.
Name any two copper releasing lUDs.
Answer:

1. NOVaT
2. Multiload 375.

Question 9.
Name any two bacterial sexually transmitted diseases.
Answer:

1. Chlamydiosis
2. Syphilis

Question 10.
What are the risk factors for cervical cancer? The risk factors for cervical cancer include:
Answer:

1. Having sex with multiple unknown partners.
2. Prolonged use of contraceptive pills.

Question 11.
Define Assisted Reproductive Technology (ART).
Assisted reproductive technology is a collection of procedures, in which the handling of gametes and/or embryos outside the body to achieve a pregnancy are carried out.

Question 12.
Define Mayer-Rokintansky syndrome.
Answer:
Mayer-Rokintansky syndrome is a condition, in which women do not have a functional uterus.

Question 13.
What is the embryo transfer technique?
Answer:
The embryo transfer technique is the method of transferring an embryo with cells more than the blastomere stage into the uterus.

Question 14.
Define Azoospermia.
Answer:
Azoospermia is defined as the absence of spermatozoa in the ejaculated semen on at least two occasions.

Question 15.
What is Foetoscope?
Answer:
Foetoscope is an instrument used to monitor the heart rate of foetus and other functions during late pregnancy and labor.

Short answer questions

Question 1.
List the health care programs taken up by the Government of India.
Answer:

1. Massive child immunization.
2. Supply of nutritional food to pregnant women.
3. Implementation of Janani Suraksha Yojana, Janani Shishu Suraksha Karyakram, RMNCH + A approach (An integrated approach for reproductive, maternal, newborn, child, and adolescent health), Pradhan Mantri Surakshit Matriva Abhiyan, etc…

Question 2.
The sex ratio in India has changed from 919 females to every 1000 males. How? Explain.
Answer:
The female foeticide and female infanticide is a manifestation of gender discrimination, in our society, which increases the female foeticide and female infanticide. This leads to the imbalance of sex ratio in our society and to correct this ratio to normal, steps are needed to change the mindset and attitude of people, especially in young adults.

Question 3.
Define lactational amenorrhoea. Explain it as a natural birth control method.
Answer:
Lactational amenorrhoea is defined as the delay in the ovarian cycle due to breastfeeding after childbirth. It serves as a natural, but unreliable form of birth control. During breastfeeding, the sucking of milk by the baby stimulates the pituitary to secrete more prolactin in order to increase milk production. The increased level of prolactin in the blood of the mother may prevent the menstrual cycle by suppressing the release of GnRH (Gonadotropin-Releasing Hormone) which in turn suppresses the production of gonadotropin from the pituitary. Thus lactational amenorrhoea indirectly acts as a natural birth control agent.

Question 4.
Write briefly about oral contraceptives.
Answer:
Oral contraceptives are taken orally in the form of pills, used to prevent ovulation in females. They inhibit the secretion of FSH and LH hormones. The most commonly used birth control pills are combined pills, which contain synthetic progesterone and estrogen hormones. Central Drug Research Institute (CDRI) in Lucknow, India developed a nonsteroidal contraceptive pill, called saheli.

Question 5.
Mention the fungal sexually transmitted disease, their causative organisms, and symptoms.
Answer:
Candidiasis: The causative organism is Candida albicans.
Symptoms: It attacks the mouth, throat, intestinal tract, and vagina. It also causes vaginal itching or soreness, abnormal vaginal discharge, and pain during urination.
Trichomoniasis: This disease is due to the fungal infection by Trichomonas vaginalis.
Symptoms: It causes vaginitis, greenish-yellow vaginal discharge, itching, and burning sensation, urethritis, epididymitis, and prostatitis.

Question 6.
What are the causes of infertility in men?
Answer:

1. Undescended testes and swollen veins (Varicocoele) in the scrotum,
2. The rise of temperature in the scrotum due to tight clothing in men may affect sperm production.
3. Underdeveloped testes.
4. Males may develop an autoimmune response to their own sperm.

Question 7.
Name any three procedures followed under assisted reproductive technology.
Answer:
The ART includes:

1. Intra Uterine Insemination (IUI)
2. In Vitro Fertilization (IVF)
3. Embryo Transfer (ET)

Question 8.
Explain intra-fallopian transfer (GIFT).
Answer:
In this technology, the ovum collected from a donor is transferred into the fallopian tube of the recipient. The transferred eggs are placed with the sperms in the fallopian tube for fertilization. The fertilized egg/zygote moves towards the uterus and gets implanted in the inner lining of the uterus.

Question 9.
What is surrogacy? Explain it briefly.
Answer:
Surrogacy is a method of assisted reproduction or an agreement whereby a woman agrees to carry a pregnancy for another person, who will become the parent of the new born child after birth. The embryos are produced through in vitro fertilization in the lab and are transferred into the uterus of a surrogate mother.

Long answer questions

Question 1.
Describe the different natural methods of birth control.
Answer:
The natural method of birth control is used to prevent the meeting of eggs with sperm.
These methods include the Rhythm method (safe period), coitus interruptus, continuous abstinence, and lactational amenorrhoea.

1. Rhythm method: In the menstrual cycle, ovulation occurs at about the 14th day and the ovum survives for about two days, whereas in the female reproductive tract, the sperms remain alive for about 72 hrs. If the coitus takes place avoiding this time, the fertilization may not take place.
2. Continuous abstinence: It is the simplest and most reliable method to avoid pregnancy. In this, it is better not to have coitus for a defined period that facilitates conception.
3. Coitus interruptus: It is the oldest family planning method, in which the male partner withdraws his penis before ejaculation, preventing the deposition of semen into the vagina.
4. Lactational amenorrhoea: After parturition, the menstrual cycle resume as early as 6-8 weeks. But during breastfeeding, the menstrual cycle is delayed for about six months due to lactational amenorrhoea. During the breastfeeding period, the sucking by the baby stimulates the pituitary to secrete more prolactin hormone in order to increase milk production. This increased concentration of prolactin in the blood suppresses the release of Gonad Stimulating Etormone from the hypothalamus, which in turn prevents the gonadotropin secretion from the pituitary, resulting in the prevention of the menstrual cycle.

Question 2.
Explain intrauterine devices (IUDs).
Answer:
Intrauterine devices are the materials inserted in the uterus through the vagina by medical experts, in order to prevent pregnancy. It is one of the popular methods of birth control with a success rate of 95 to 99% in India. These devices include

1. Copper releasing IUDs
2. Hormone releasing IUDs and
3. Non-medicated IUDs. IUDs increase phagocytosis of sperm within the uterus and are the ideal contraceptive for women.

(i) Copper releasing IUDs: Copper releasing IUDs are CuT-380A, NovaT, Cae7, CuT 380 Ag, Multiload 375 etc., and they differ from each other by the amount of copper they release as free copper or copper salts into the uterus and prevent sperm motility. They can remain in the uterus for five to ten years.
(ii) Hormone releasing IUDs:
releasing IUDs are progestagen and ING – 20, which are often called as intrauterine systems (IUS). They prevent sperms from entering the cervix by increasing the viscosity of the cervical mucus.
(Hi) Non-medicated IUDs: They are made up of stainless steel or plastic. Double ‘S’ shaped plastic lippes loop is a typical example of a non-medicated IUD.

Question 3.
Describe the method of surgical sterilization.
Answer:
Surgical sterilization methods are permanent birth control methods known as vasectomy in males and tubectomy in females. They block the transport of gametes and prevent fertilization.
(i) Vasectomy: Vasectomy is the male sterilization through a surgical procedure. In this, both the vas deferens are cut and tied through a small incision on the scrotum in order to prevent the entry of sperm into the urethra. Hence the discharge from the penis has no sperms and has no chance of fertilization.
(ii) Tubectomy: The tubectomy is the surgical sterilization in females, in which a small portion of fallopian tubes is cut and tied up through a small incision in the abdomen or through the vagina. This prevents the entry of eggs into the uterus as well as fertilization.

Question 4.
What is cervical cancer? Explain its causes and preventions.
Answer:
Cervical cancer is the abnormal growth of cervical cells or cervical dysplasia, caused by a sexually transmitted virus namely Human Papilloma Virus (HPV).
The Pelvic pain, increased vaginal discharge and abnormal vaginal, bleeding are the symptoms of cervical cancer. Prolonged use of contraceptive pills and having multiple sexual partners are the major risk factors.
Cervical cancer can be diagnosed by a PAP smear (Papanicolaou smear) combined with an HPV test. The stages of cancer can be detected by X-ray, CT scan, MRI and PET scan. Radiotherapy, surgery, and chemotherapy are the options of treatment for cervical cancer.
The precancerous changes in the cervical region can be detected by modem screening techniques and therefore cervical cancer screening can be done for women above 30 years of age once a year. Now vaccination to prevent cervical cancer is available and the HPV vaccination can be given to girls aged between 9-13 years before they attain puberty. Cervical cancer can be prevented by modifications in lifestyle such as having a healthy diet, avoiding tobacco usage, preventing early marriages, practicing monogamy, and regular exercise.

Question 5.
Describe the method of In Vitro Fertilization (IVF).
Answer:
In vitro fertilization is the procedure in which sperm and eggs are allowed to fertilize outside the body in the laboratory. After fertilization, one or more fertilized eggs are introduced into the uterus of a woman, where they may implant in the wall of the uterus and develop. The excess fertilized eggs can be preserved for future use through cryopreservation. This technique was first used to treat women with blocked, damaged, or absent fallopian tubes. Nowadays this technique is used to treat many cases of infertility. The basic steps involved in IVF treatment include ovarian stimulation, egg retrieval, fertilization, embryo culture, and embryo transfer.
After 34 to 37 hrs of hCG (human chorionic gonadotropin) injection, an egg from the ovary is retrieved by minor surgery under anesthesia, using an ultrasound guide. Eggs are prepared by stripping from the surrounding cells. At the same time, sperm preparation is also carried out in special media. For each egg, 10000 – 1,00,000 sperms are needed and the eggs and sperms are brought together for fertilization. The fertilized egg or the zygote is then allowed to divide and form 8 celled blastomere, which is transferred into the uterus for further growth.
The embryo transfer technique is the transfer of an embryo with more than 8 celled blastomere stage into the uterus.

Choose the correct answers.

1. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(b) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)

2. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

3. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
Answer:
(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)

4. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

5. In which year Family planning programme was initiated:
(a) 1957
(b) 1962
(c) 1951
(d) 1953
Answer:
(c) 1951

6. An ideal contraceptive should be:
(a) User friendly
(b) Easily available
(c) With least side effect
(d) All the above
Answer:
(d) All the above

7. When is Justice Verma committe instituted?
(a) 2011
(b) 2016
(c) 2013
(d) 2003
Answer:
(c) 2013

8. W uch of the following is sexually transmitted disease?
(a) Elephantiasis
(b) Hepatitis B
(c) Gonorrhoea
(d) Liver cirrhosis
Answer:
(c) Gonorrhoea

9. Choose the odd man out:
(a) Gonorrhoea
(b) Chlamydiasis
(c) Candidiasis
(d) Lymphogranuloma venereum
Answer:
(c) Candidiasis

10. Find the odd one out:
(a) Rhythm method
(b) Copper IUD
(c) LNG 20
(d) Condom
Answer:
(a) Rhythm method

11. Indicate the odd one out:
(a) Ultra sound scanning
(b) Amniocentesis
(c) Foetoscope
(d) Mammogram
Answer:
(d) Mammogram

12. Choose the odd one out:
(a) Continuous abstinence
(b) Melting suppositories
(c) Coitus interruptus
(d) Lactational Amenorrhoea
Answer:
(b) Melting suppositories

13. Choose the correct pair:

Answer:
(c)

14. Indicate the incorrect pair:


Answer:
(d)

15. Choose the correct pair:

Answer:
(a)

16. Choose the incorrect pair:

Answer:
(c)

17. Assertion: Creating awareness and providing medical assistance to people can build a healthy society.
Reason: Introducing sex education in schools provides information about adolescence among school children.
(a) Both Assertion and Reason are true, the reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true, the reason is not the correct explanation of assertion.
(c) Assertion is false, Reason is true.
(d) Assertion is true, Reason is false
(e) Both Assertion and Reason are false.
Answer:
(b) Both Assertion and Reason are true, the reason is not the correct explanation of assertion.

18. Assertion: Increased health facilities and better living conditions have enhanced longivity.
Reason: Because they have reduced the mortality due to disease and other living conditions.
(a) Both Assertion and Reason are true, the reason is the correct explanation of assertion.
(b) Both Assertion and Reason are true, the reason is not the correct explanation of assertion.
(c) Assertion is false, Reason is true.
(d) Assertion is true, Reason is false
(e) Both assertion and Reason are false.
Answer:
(a) Both Assertion and Reason are true, the reason is the correct explanation of assertion.

19. Assertion: Oral pills are used to prevent ovulation by inhibiting the secretion of FSH and LH hormones.
Reason: It contains synthetic Gonad Stimulating Hormones.
(a) Both Assertion and Reason are true, the reason is the correct explanation of assertion.
(b) Both Assertion and Reason are true, the reason is not the correct explanation of assertion.
(c) Assertion is false, Reason is true.
(d) Assertion is true, Reason is false.
(e) Both Assertion and Reason are false.
Answer:
(d) Assertion is true, Reason is false.

20. Assertion: Cervical cancer is caused by a sexually transmitted HIV virus.
Reason: The risk factors for cervical cancer include having sex with multiple unknown partners and prolonged use of contraceptive pills.
(a) Both Assertion and Reason are true, the reason is the correct explanation of assertion.
(b) Both Assertion and Reason are true, the reason is not the correct explanation of assertion.
(c) Assertion is false, Reason is true.
(d) Assertion is true, Reason is false.
(e) Both Assertion and Reason are false.
Answer:
(c) Assertion is false, Reason is true.

21. Which of the following statement is true?
(a) The sexually transmitted disease, syphilis is caused by a bacteria called Clamidia trachomatis.
(b) Syphilis is caused by a virus.
(c) Syphilis is due to fungal infection.
(d) All the above are not correct.
Answer:
(d) All the above are not correct.

22. Choose the incorrect statement:
(a) Diaphragms are made up of rubber.
(b) Diaphragms are one of the natural birth control methods.
(c) Saheli is a contraceptive pill developed by Central Drug Research Institute, Lucknow.
(d) None of the above.
Answer:
(b) Diaphragms are one of the natural birth control methods.

23. Indicate the correct statement:
(a) Amniocentesis is a prenatal technique used to detect any chromosomal abnormalities in the foetus.
(b) Amniocentesis is used to measure heart rate of foetus in the uterus.
(c) Amniocentesis is used to measure the kidney function in foetus.
(d) Amniocentesis is used to measure blood flow from mother to foetus.
Answer:
(a) Amniocentesis is a prenatal technique used to detect any chromosomal abnormalities in the foetus.

24. Which of the following statement is wrong?
(a) Ovulation occurs at about 14th day of normal menstrual cycle.
(b) The ovum survives for about 2 days.
(c) Sperm remains alive for about 48 hrs in the female reproductive tract.
(d) None of the above.
Answer:
(c) Sperm remains alive for about 48 hrs in the female reproductive tract.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 2 Human Reproduction which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 2 Human Reproduction

Very short answer questions

Question 1.
Define Gametogenesis.
Answer:
Gametogenesis is defined as a process, through which the formation of male and female gametes are produced.

Question 2.
Name two reproductive hormones secreted by the pituitary gland.
Answer:

1. Follicle Stimulating Hormone (FSH).
2. Luteinizing Hormone (LH).

Question 3.
Define organogenesis.
Answer:
Organogenesis is a series of events through which the formation of specific tissues, organs, and organ systems from three germ layers takes place.

Question 4.
What are Sertoli cells? Explain its functions.
Answer:
Sertoli cells are one of the two types of cells of the seminiferous tubule. It provides nourishment to the sperm till maturation. It also secretes a hormone namely inhibin, which is involved in the negative feedback control of sperm production.

Question 5.
Leydig cells are endocrine in nature. Justify.
Answer:
Leydig cells are endocrine in nature because they secrete a hormone, androgens namely testosterone, which initiates the process of spermatogenesis.

Question 6.
Name the accessory ducts associated with the male reproductive system.
Answer:

1. Rete testis.
2. Vasa efferentia.
3. Epididymis.
4. Vas deferens.

Question 7.
Explain the function of the seminal vesicle.
Answer:
Seminal vesicles secrete an alkaline fluid, containing fructose sugar, ascorbic acid, prostaglandins. It also secretes a coagulating enzyme called vesiculate, which helps in sperm motility.

Question 8.
Mention the female accessory reproductive organs.
Answer:

1. Fallopian tube.
2. Uterus.
3. Vagina.

Question 9.
What are the three layers of the uterus wall?
Answer:
The wall of the uterus has three layers of tissue namely the perimetrium, myometrium, and endometrium.

Question 10.
Explain the functions of the skene’s gland.
Answer:
The skene’s glands are present on the anterior wall of the vagina, surrounding the lower end of the urethra. These glands secrete a lubricating fluid.

Question 11.
Define spermiogenesis.
Answer:
Spermiogenesis is a process in which a spermatid is transformed into spermatozoa or sperms.

Question 12.
Explain the term mitochondrial spiral.
Answer:
Mitochondrial spiral is the spirally twisted mitochondria around the axial filament of the middle piece of sperm.

Question 13.
What are the phases of the menstrual cycle?
Answer:

1. Menstrual phase
2. Follicular phase
3. Ovulatory phase
4. Luteal or secretory phase.

Question 14.
Explain briefly about LH surge.
Answer:
In the middle of the ovulatory phase, maximum secretion of LH, known as LH surge takes place. This in term induces the rupture of the Graafian follicle, resulting in the release of the ovum from the ovary wall into the peritoneal cavity.

Question 15.
What is meant by menopause?
Answer:
Menopause is a phase, in which ovulation and menstruation stop in a woman’s life.

Question 16.
Explain the morula stage.
Answer:
The morula stage of the human embryo in which a loose collection of cells into a berry-shaped cluster of 16 or more cells is formed after 72 hours of fertilization.

Question 17.
Define monozygotic twins.
Answer:
When a single fertilized egg splits into two during the first cleavage, each daughter egg develops into each individual forming identical twins.

Question 18.
Define parturition.
Answer:
Parturition is the completion stage of pregnancy and childbirth.

Question 19.
What is colostrum?
Answer:
Colostrum is a yellow fluid secreted by the mammary gland during the initial few days after parturition.

Question 20.
Expand the following abbreviations:
Answer:
(i) WABA,
(ii) WHO,
(i) WABA: World Alliance for Breastfeeding Action.
(ii) WHO: World Health Organisation.

Short answer questions

Question 1.
What is the constitution of the seminiferous tubule?
Answer:
The seminiferous tubule is made up of two types of stratified epithelium namely Sertoli cells or nurse cells and spermatogenic cells or male germ cells. Sertoli cells are elongated and pyramidal cells, which nourish the growing sperm. They also secrete a hormone namely inhibin, which is responsible for the negative feedback control of sperm production. Spermatogenic cells form the spermatozoa by meiosis or reduction division.

Question 2.
Distinguish between Sertoli cells and Leydig cells.
Answer:

Question 3.
Write down the functions of the accessory glands of the male reproductive system.
Answer:
The accessory glands of the male reproductive system are:

1. Seminal vesicle.
2. Bulbourethral gland or Cowper’s gland.
3. Prostate gland.

Seminal vesicles:
secrete seminal plasma having fructose sugar, ascorbic acid, prostaglandins, and a coagulating enzyme, namely vesiculase, which helps sperm motility. The seminal plasma is alkaline in nature.
Bulbourethral glands: They secrete a lubricating fluid and helps in the lubrication of the penis.
Prostate gland: It secretes a slightly acidic fluid containing citrate, several enzymes, and prostate-specific antigens.

Question 4.
Explain the structure of the penis.
Answer:
The penis is a male copulatory organ, made up of special tissues which facilitate the erection of the penis to deliver the seminal fluid in the vagina of the female. The enlarged end of the penis is called the glans penis. It is covered by a loose fold of skin called foreskin or prepuce. The structure of the penis facilitates insemination.

Question 5.
Describe the structure of Uterus.
Answer:
The Uterus is otherwise called a womb, which is an inverted pear-shaped structure. It is a hollow thick-walled and highly vascularized structure lying between the urinary bladder and the rectum in the pelvic cavity. The body of the uterus occupies the major portion and the fundus is the rounded region superior to it.
Cervix is the narrow opening of the uterus into the vagina. The external orifice and internal orifice through which the cervical canal opens communicates with the vagina and with the uterus respectively. The birth canal is formed by the cervical canal and vagina.

Question 6.
Distinguish between Bartholin’s glands and skene’s glands.
Answer:

Question 7.
Explain briefly the normal development of the breast.
Answer:
The normal development of breasts in females takes place at puberty and progresses with changes in each menstrual cycle. The breast size is mainly due to fat deposits. The glandular structure is underdeveloped in a non-pregnant women. In pregnant women, the glandular structure develops. The efficiency of lactation does not have any influence on the size of the breast.

Question 8.
Name the important hormones involved in spermatogenesis.
Answer:

1. Gonadotropin-Releasing Hormone (GnRH).
2. Follicle Stimulating Hormone (FSH).
3. Luteinizing Hormone (LH).

Question 9.
Write down the events in the follicular phase of the menstrual cycle.
Answer:
The follicular phase of the menstrual cycle extends from the 5th day of the cycle until the time of ovulation. During this phase, a fully mature Graafian follicle is formed from the primary follicle in the ovary. Simultaneously, the endometrium regenerates through proliferation. The secretion of FSH and LH during this phase induces these changes in the ovary and uterus. The follicular cells secrete oestrogen during this phase.

Question 10.
What is meant by implantation?
Answer:
The fertilized egg undergoes cleavage and forms a fluid-filled hollow ball of about 100 cells, called the blastocyst. Under the influence of progesterone, the embryo moves through the fallopian tube into the uterine cavity and becomes embedded in the endometrium of the uterus and this process is called implantation.

Question 11.
Name the hormones secreted by the placenta during pregnancy.
Answer:

1. Human Chorionic Gonadotropin (HCG).
2. Human Chorionic Somatomammotropin (HCS) or Human Placental Lactogen (HPL).
3. Oestrogens and Progesterone.

Question 12.
What is meant by Polycystic Ovary Syndrome (PCOS).
Answer:
PCOS is a complex endocrine disorder. This affects women in their reproductive phase of the year.
This is mainly due to the formation of many partially formed follicles which contain an egg each. These eggs do not grow to maturity and take part in fertilization. The symptoms of this syndrome include irregular menstrual cycles, increased androgen levels, excessive facial and body hair growth, acne, obesity, reduced fertility, and increased risk of diabetes.

Long answer questions

Question 1.
Write about the accessory glands of the male reproductive system.
Answer:
The accessory glands associated with the male reproductive system include the following:
(a) A paired seminal vesicles.
(b) Bulbourethral glands or Cowper’s glands.
(c) A single prostate gland.

1. Seminal vesicles: Seminal vesicles are located on either side of the prostate gland and secrete an alkaline fluid called seminal plasma, which contains fructose sugar, ascorbic acid, prostaglandins, and a coagulating enzyme called vesiculates, which helps sperm motility.
2. The Bulbourethral glands: These glands are located inferior to the prostate gland and they secrete a lubricating fluid, which helps to lubricate the penis.
3. The prostate glands: The single prostate gland is placed just below the urinary bladder, encircling the urethra. It secretes slightly acidic fluid, which contains citrate, several enzymes and prostate-specific antigens.
   The secretions of the three glands along with sperm is called semen or seminal fluid.

Question 2.
Draw the diagrammatic view of the female reproductive system and label the parts.
Answer:

Question 3.
Give an account of mammary glands.
Answer:
Mammary glands are modified sweat glands present in both sexes. It is functional in females and rudimentary in males. In humans, a pair of mammary glands is placed in the thoracic region. The glandular tissues and variable quantities of fat are present in mammary glands along with a median nipple. The nipple is surrounded by a pigmented area called the areola. The areolar glands, modified sebaceous glands are present on the surface. They help in reducing the cracking of the skin of the nipple.
Each mammary gland consists of 2 – 25 lobes. They are separated by fat and connective tissues. Each lobe contains many lobules, which contain acini or alveoli lined by epithelial cells. Milk is secreted by the cells of alveoli, which opens into mammary tubules. The mammary duct is formed by joining the tubules of each lobe. The mammary ampulla is formed by joining several mammary ducts. The mammary duct is connected to the lactiferous duct in the nipple. The lactiferous sinus is the expansion of the lactiferous duct under the nipple and serves as a reservoir of milk. On the surface of the nipple, each lactiferous duct opens by a minute pore.

Question 4.
Explain the sequence of events in the fertilization process in humans.
Answer:
Fertilization is a process in which a haploid male gamete fuses with a haploid ovum to form a diploid zygote.
The sperms are deposited in the female reproductive tract by copulation and sperms undergo a process called capacitation. It is a biochemical event that enables the sperm to penetrate through the egg membrane and fertilize the egg.
Fertilization of the ovum takes place only if the ovum and sperm are deposited simultaneously to the ampullary isthmic junction of the fallopian tube.
The sperm has to penetrate the multiple layers of granulosa, which are around the ovum forming corona radiata. The follicular cells are held together by hyaluronic acid, an adhesive substance. The acrosome of the sperm secretes a proteolytic enzyme, hyaluronidase, which lysis the membrane and helps the penetration of sperm through corona radiata and zona pellucida. The process is called acrosomal reaction. Once fertilization is over, a barrier membrane, the fertilization membrane around the ovum is formed by the cortical granules from the cytoplasm of the ovum. This membrane prevents further entry of other sperms. Thus polyspermy is prevented.

Choose the correct answers.

Question 1.
Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)

Question 2.
Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(iii); (r)-(iv); (s)-(i)
(d) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
Answer:
(c) (p)-(ii); (q)-(iii); (r)-(iv); (s)-(i)

Question 3.
Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(i); (r)-(iv); (s)-(ii)
Answer:
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

Question 4.
Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

Question 5.
Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(iii); (q)-(i); (r)-(iv); (s)-(ii)
Answer:
(b) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)

Question 6.
The fusion of male and female gametes is called as:
(a) Oogenesis
(b) Fertilization
(c) Gastrulation
(d) Spermiation
Answer:
(b) Fertilization

Question 7.
The hormone inhibin is secreted by:
(a) Pituitary
(b) Leydig cells
(c) Sertoli cells
(d) Endometrium
Answer:
(c) Sertoli cells

Question 8.
The bulbourethral gland is otherwise called as:
(a) Prostate gland
(b) Seminal vesicle
(c) Cowper’s gland
(d) Skene’s gland
Answer:
(c) Cowper’s gland

Question 9.
The mammary glands are modified:
(a) Sebaceous glands
(b) Green glands
(c) Sweat glands
(d) Bartholin’s gland
Answer:
(c) Sweat glands

Question 10.
The acrosomal membrane disintegrates by the proteolytic enzyme called:
(a) Leutinising hormone
(b) Hyaluronidase
(c) Lactogenase
(d) Prolactin
Answer:
(b) Hyaluronidase

Question 11.
Choose the odd man out:
(a) human Chorionic Gonadotropin
(b) Follicle Stimulating Hormone.
(c) human Chorionic Somatomammotropin
(d) human Placental Lactogen.
Answer:
(b) Follicle Stimulating Hormone.

Question 12.
Choose the odd one.
(a) Seminal vesicle
(b) Prostate gland
(c) Cowper’s gland
(d) Bartholin’s gland
Answer:
(d) Bartholin’s gland

Question 13.
Indicate the odd one.
(a) Gametogenesis
(b) Spermiogenesis
(c) Spermatogenesis
(d) Oogenesis
Answer:
(b) Spermiogenesis

Question 14.
Choose the odd man out.
(a) Hyaluronidase
(b) FSH – Follicle Stimulating Hormone
(c) LH – Lutenizing Hormone
(d) ABP – Androgen Binding Protein
Answer:
(a) Hyaluronidase

15. Find out the odd one.
(a) Labia majora
(b) Labia minora
(c) Zona pellucida
(d) Hymen
Answer:
(c) Zona pellucida

16. Choose the correct pair.

Answer:
(b)

17. Which of the following pair is wrong?

Answer:
(c)

18. Choose the correct pair.

Answer:
(d)

19. Choose the incorrect pair.

Answer:
(a)

20. Which of the following is the correct pair?

Answer:
(b)

21. Assertion: Leydig cells surrounding the seminiferous tubules are endocrine in nature.
Reason: They secrete testosterone hormone which initiates the process of spermatogenesis.
(a) Assertion and Reason are true, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are true, Reason is not the correct explanation of Assertion.
(c) Assertion is true, Reason is false.
(d) Both Assertion and Reason are false.
Answer:
(a) Assertion and Reason are true, Reason is the correct explanation of Assertion.

22. Assertion: The seminal vesicles secrete a slightly acidic fluid called seminal plasma.
Reason: Seminal plasma helps in the movement of the sperm.
(a) Assertion and Reason are true, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are true, Reason is not the correct explanation of Assertion.
(c) A is true, Reason is false.
(d) Both Assertion and Reason are false.
Answer:
(d) Both Assertion and Reason are false.

23. Assertion: The medulla of the ovarian stroma is a loose connective tissue with abundant blood vessels, lymphatic vessels and nerve fibres.
Reason: in the medulla, the various stages of ovarian follicles are present.
(a) Assertion and Reason are true, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are true, Reason is not the correct explanation of Assertion.
(c) Assertion is true, Reason is false.
(d) Both Assertion and Reason are false.
Answer:
(c) Assertion is true, Reason is false.

24. Assertion: Acrosome is a small cup-like pointed structure at the tip of the nucleus of sperm, which helps the sperm to penetrate the ovum during fertilization.
Reason: Acrosome contains a proteolytic enzyme, hyaluronidase popularly known as sperm lysin which helps to penetrate the ovum during fertilization.
(a) Assertion and Reason are true, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are true, Reason is not the correct explanation of Assertion.
(c) Assertion is true, Reason is false.
(d) Both Assertion and Reason are false.
Answer:
(a) Assertion and Reason are true, Reason is the correct explanation of Assertion.

25. Assertion: During the luteal phase of the menstrual cycle, the Graafian follicle is transformed into a transitory endocrine gland called the corpus luteum.
Reason: Corpus luteum secretes a large amount of Oestrogen, which is essential for the maintenance of the endometrium.
(a) Assertion and Reason are true, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are true, Reason is not the correct explanation of Assertion.
(c) Assertion is true, Reason is false.
(d) Both Assertion and Reason are false.
Answer:
(c) Assertion is true, Reason is false.

26. Which of the following a correct statement?
(a) At the end of gametogenesis in females, each primary Oocyte gives rise to only one haploid ovum.
(b) At the end of gametogenesis in females, each primary Oocytes gives rise to four haploid ovum.
(c) At the end of gametogenesis in females, each primary Oocyte gives rise to three polar bodies and two ovum.
(d) None of the above.
Answer:
(a) At the end of gametogenesis in females, each primary Oocyte gives rise to only one haploid ovum.

27. Choose the incorrect statement:
(a) Human ovum is non-cleidoic in nature.
(b) Human ovum is alecithal in nature.
(c) Human ovum contains a small nucleus in the cytoplasm.
(d) Human ovum is microscopic in nature.
Answer:
(c) Human ovum contains a small nucleus in the cytoplasm.

28. Indicate the correct statement:
(a) The Acrosome of sperm possess nebenkem.
(b) The middle piece of sperm contain a mitochondrial spiral.
(c) The proximal centriole of sperm gives rise to the axial filament.
(d) None of the above.
Answer:
(b) The middle piece of sperm contain a mitochondrial spiral.

29. Choose the incorrect statement:
(a) Inhibin is a hormone involved in the negative feedback control of sperm production.
(b) Leydig cells are endocrine in nature.
(c) Vesiculase enzyme is a proteolytic enzyme.
(d) Corpus luteum secretes lot of progesterone.
Answer:
(c) Vesiculase enzyme is a proteolytic enzyme.

30. Which of the following is a correct statement?
(a) Mammary glands are modified sebaceous glands.
(b) It is functional in males and rudimentary in females.
(c) Mammary glands are modified sweat gland.
(d) None of the above.
Answer:
(c) Mammary glands are modified sweat gland.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 1 Reproduction in Organisms which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 1 Reproduction in Organisms

Very short answer questions

Question 1.
Define binary fission.
Answer:
Binary fission is the process, in which the parent organism divide into two halves and each half grows into a daughter individual. Eg: Amoeba.

Question 2.
Mention any two types of binary fission.
Answer:

1. Transverse binary fission.
2. Longitudinal binary fission.

Question 3.
What type of binary fission is seen in dinoflagellates? Explain briefly.
Answer:
The asexual reproduction seen in dinoflagellates is through oblique binary fission, in which the plane of division is oblique.

Question 4.
Define strobilation.
Answer:
Strobilation is a special type of transverse fission, in which several transverse fission occur simultaneously, resulting in a number of individuals. Eg: Aurelia.

Question 5.
Define plasmogamy.
Answer:
Plasmotomy is the reproductive process in which the division of multinucleated parent into many multinucleate daughter individuals with the division of nuclei.

Question 6.
Explain briefly about gemmules.
Answer:
Gemmules are the endogenous buds produced by freshwater sponges for asexual reproduction.

Question 7.
Define archetypes.
Answer:
Archeocytes are the fully grown gemmules and are hard ball-like structures consisting of an internal food-laden mass, seen in freshwater sponges.

Question 8.
Mention briefly about fragmentation type of reproduction.
Answer:
In fragmentation type of asexual reproduction, the parent body breaks into many pieces, and each piece has the potential to grow into a new individual.

Question 9.
Define apolysis.
Answer:
Apolysis is the process in which the gravid proglottids of Taenia solium are regularly detached either singly or in groups from the posterior end.

Question 10.
Explain hologamy.
Answer:
Hologamy is the type of sexual reproduction in lower organisms, in which the entire mature organisms acts as gamete and fusion of such gametes takes place.
Eg: Trichonympha.

Question 11.
Define parthenogenesis.
Answer:
Parthenogenesis is defined as the development of an egg into a complete individual without fertilization.

Question 12.
What is meant by paedogenesis?
Answer:
Paedogenesis is the process in which the larvae produce a new generation of larvae through parthenogenesis. Eg: Larvae of Gall fly.

Question 13.
Define Ovoviviparous.
Answer:
Ovoviviparous animals are those animals in which the embryo develops inside the egg, which remains in the body of mother until they are ready to hatch. Eg: Shark.

Question 14.
Explain restorative regeneration.
Answer:
Restorative regeneration is the process of regeneration, in which restoration of the entire part of organisms, which is severed. Eg: The tail of the wall lizard.

Question 15.
Mention the two types of regeneration.
Answer:

1. Morphallaxis
2. Epimorphosis

Short answer questions

Question 1.
Mention the different modes of asexual reproduction.
Answer:
The different modes of asexual reproduction seen in animals are fission, sporulation, budding, gemmule formation, fragmentation, and regeneration.

Question 2.
Distinguish between binary fission and multiple fission.
Answer:

Question 3.
Explain the type of multiple fission in Plasmodium.
Answer:
In Plasmodium, multiple fission occurs in its two stages namely schizont and oocyte stage. In the schizont stage, the process of multiple fission is called schizogony and the offsprings are known as merozoites. In the oocyte stage, multiple fission occurs by sporogony, and the offsprings are called sporozoites.

Question 4.
Distinguish between strobilation and sporulation.
Answer:

Question 5.
Explain the exogenous type of budding with an example.
Answer:
Exogenous budding is one type of asexual reproduction, in which the buds are formed on the outer surface of the parent body.
Eg: Hydra.
In Hydra, when food is plenty, a small elevation on the outer surface of the body is formed by the increase of ectoderm cells. Then ectoderm and endoderm are pushed out to form a bud. The bud develops an interior lumen in continuation with the gastrovascular cavity of the parent. Subsequently, the bud develops mouth and tentacles at the free end. When it is grown fully, a constriction develops at the base of the bud and finally, it detaches from the parent to lead an independent life.

Question 6.
Draw and label the structure of a gemmule of sponge.
Answer:

Question 7.
Distinguish between fragmentation and regeneration.
Answer:

Question 8.
Mention the three types of sexual reproduction in animals for example.
Answer:

1. Oviparous – Reptiles and Aves
2. Viviparous – Mammals
3. Ovoviviparous – Shark.

Question 9.
Name the three types of natural parthenogenesis.
Answer:

1. Arrhenotoky – Honey bees
2. Thelytoky – Solenobia
3. Amphitoky – Aphis.

Question 10.
Name any three animals, whose eggs are without calcareous shells.
Answer:

1. Carp
2. Frog
3. Catfish

Long answer questions

Question 1.
What are the types of binary fission? Explain each with an example.
Answer:
There are four types of binary fission namely

1. Simple irregular binary fission
2. Transverse binary fission
3. Longitudinal binary fission
4. Oblique binary fission.

Simple binary fission: This type of binary fission is present in irregularly shaped organisms like Amoeba. Before division, the contractile and nucleolus disappear. The nucleus divides mitotically followed by the division of the cytoplasm through making a constriction in the middle. The daughter cells are formed.
Transverse binary fission: In this, the division takes place along the transverse axis of the individual. The macronucleus divides by amitosis and the micronucleus divides by mitosis.
Eg: Paramecium andplanaria.
Longitudinal binary fission: In this type of fission, the organism divides in the longitudinal axis. Eg: Flagellates when the cell divides longitudinally, one of the daughter cells retains the flagellum. The other daughter cell develops a new flagellum from the new basal granule.
Eg: Vorticella and Euglena.
Oblique binary fission: In this type, the division takes place on the plane of oblique. Eg: Ceratium.

Question 2.
Describe the process of budding in Hydra.
Answer:
In Hydra, the exogenous type of budding takes place. Under the favourable condition, i.e., when plenty of food is available, the ectoderm cells divide and increase in number. They form a small elevation on the body surface. This leads to the formation of bud by pushing ectoderm and endoderm outside. The bud then develops an internal lumen, which is continuous to the gastrovascular cavity of the parent. The bud grows larger and develops a mouth and tentacles at the free end. When it is fully grown, a constriction and developed at the base of the bud finally detaches from the parent body. Each detached bud leads an independent life.

Question 3.
Explain the types of regeneration with suitable example.
Answer:
Abraham Trembley was the first scientist to demonstrate regeneration in Hydra. Regeneration is the process of regrowth of injured tissue or part of the organism. There are two types of regeneration namely morphallaxis and epimorphosis. In morphallaxis, a small fragment of the parent body grows into a whole body. Eg: Hydra and planaria. When planaria are accidentally cut into many pieces, each piece can regenerate lost part and forms the whole body. The parts usually retain their original polarity. The portion with basal discs develops oral ends with mouth and tentacles and the oral portion generate the basal disc in Hydra.
Epimorphosis is the replacement of lost body parts. It is of two types namely reparative and restorative regeneration. In reparative regeneration, only certain damaged tissue can be regenerated, whereas in restorative regeneration, the detached body part can be regenerated.
Eg: Starfish, the tail of wall lizard.

Question 4.
Draw and label the events of binary fission in Amoeba and paramecium.
Answer:

Question 5.
Explain the sporulation in the amoeba with the help of a diagram.
Answer:
Amoeba multiplies by sporulation without encystments during the unfavourable condition. Chromatin blocks or fragments of the nucleus are formed by breaking of parent nucleus. Each chromatin block develops a nuclear membrane, surrounded by a layer of cytoplasm. This forms a spore-case around it. When the conditions become favourable, the spores are liberated after the disintegration of the parent body. Each spore forms a young amoeba.

Choose the correct answers.

1. Match the following:


(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(b) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)

2. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(n); (q)-(i); (r)-(iv); (s)-(iii)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

3. Match the following:

(a) (p)-(ii); (q)-(iii); (r)-(iv); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(a) (p)-(ii); (q)-(iii); (r)-(iv); (s)-(i)

4. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)

5. Asexual reproduction is not common in:
(a) Protista
(b) Bacteria
(c) Archaea
(d) Reptelia
Answer:
(d) Reptilia

6. Asexual reproduction through gemmule formation is found in:
(a) Aurelia
(b) Sponges
(c) Plasmodium
(d) Hydra
Answer:
(b) Sponges

7. During unfavourable multiplies by:
(a) Fragmentation
(b) Binary fission
(c) Sporulation
(d) Budding
Answer:
(c) Sporulation

8. The tail of wall lizard is regenerated by a process called:
(a) Morphallaxis
(b) Epimorphosis
(c) Reparative regeneration
(d) Restorative regeneration
Answer:
(d) Restorative regeneration

9. Choose the odd man out:
(a) Simple binary fission
(b) Transverse binary fission
(c) Multiple fission
(d) Longitudinal binary fission
Answer:
(c) Multiple fission

10. Indicate the odd one out:
(a) Strobilation
(b) Proglotids
(c) Sporulation
(d) Plasmotomy
Answer:
(b) Proglotids

11. Find out the odd one out:
(a) Autogamy
(b) Hologamy
(c) Exogamy
(d) Monogamy
Answer:
(d) Monogamy.

12. Choose the odd one in relation to reproduction:
(a) Birds
(b) Frog
(c) Shark
(d) House lizard
Answer:
(c) Shark

13. Choose the correct pair.

Answer:
(c)

14. Indicate the incorrect pair.

Answer:
(b)

15. Find out the correct pair.

Answer:
(d)

16. Choose the incorrect pair.

Answer:
(c)

17. Assertion: The offsprings produced by asexual reproduction are genetically identical.
Reason: They are produced by mitotic or amitotic cell division.
(a) Assertion is true; the reason is false.
(b) Assertion is false; the reason is true.
(c) Both assertion and reason are true.
(d) Both assertion and reason are false.
Answer:
(c) Both assertion and reason are true.

18. Assertion: In planaria, the plane of division runs along the longitudinal axis of the individual.
Reason: They are bilaterally symmetrical.
(a) Assertion is true; the reason is false.
(b) Assertion is false; the reason is true.
(c) Both assertion and reason are true.
(d) Both assertion and reason are false.
Answer:
(d) Both assertion and reason are false.

19. Assertion: During unfavourable conditions, the freshwater sponges disintegrate, but the gemmule can withstand adverse conditions.
Reason: Gemmules are hard balls consisting of an internal mass of food ladenarchaeocytes.
(a) Assertion is true; the reason is false.
(b) Assertion is false; the reason is true.
(c) Both assertion and reason are true.
(d) Both assertion and reason are false.
Answer:
(c) Both assertion and reason are true.

20. Assertion: In Taenia solium the gravid proglottids are regularly cut off either singly or in groups from the posterior end by a process called apolysis.
Reason: It helps in transferring the developed embryos from the primary host (man) to find a secondary host (pig).
(a) Assertion is true; the reason is false.
(b) Assertion is false; the reason is true.
(c) Both assertion and reason are false.
(d) Both assertion and reason are true.
Answer:
(d) Both assertion and reason are true.

21. Which of the following statement is correct?
(a) Exogenous budding is present in Paramecium.
(b) Endogenous budding is present in Euglena.
(c) Pedal laceration occurs in many genera of sea anemones.
(d) Gemmules are produced in Hydra.
Answer:
(c) Pedal laceration occurs in many genera of sea anemones.

22. Choose the incorrect statement.
(a) In some metazoan animal, a special type of transverse fission called strobilation occurs.
(b) Amoeba withdraws its pseudopodia during an increase in temperature.
(c) Plasmotomy occurs in Aurelia.
(d) During unfavourable conditions amoeba multiplies by sporulation.
Answer:
(c) Plasmotomy occurs in Aurelia.

23. Which of the following statement is wrong?
(a) Regeneration was first studied in Hydra by Abraham Trembley.
(b) Epimorphosis is the replacement of lost body parts.
(c) In morphallaxis the whole body grows from a small fragment.
(d) None of the above statements is correct.
Answer:
(d) None of the above statements is correct.

24. Indicate the correct statement.
(a) In Arrhenotoky, only females are produced by parthenogenesis.
(b) In Arrhenotoky, only males are produced by parthenogenesis.
(c) In Amphitoky, only females are produced by parthenogenesis.
(d) In Thelytoky, both male and female are produced by parthenogenesis.
Answer:
(b) In Arrhenotoky, only males are produced by parthenogenesis.

25. Which of the following statement is incorrect?
(a) In oviparous animals, the young hatch from the eggs laid outside the mother’s body.
(b) In fishes, the eggs are not covered by calcareous shells.
(c) In ovoviviparous animals the embryo develops inside the mother’s body with the placenta.
(d) Viviparous animals give rise to young ones.
Answer:
(c) In ovoviviparous animals the embryo develops inside the mother’s body with the placenta.

TN 12th Bio Zoology Important Questions State Board English Medium 2022-2023.

Biology NEET MCQ

TN State Board 12th Bio Zoology Important Questions and Answers

• Chapter 1 Reproduction in Organisms Important Questions
• Chapter 2 Human Reproduction Important Questions
• Chapter 3 Reproductive Health Important Questions
• Chapter 4 Principles of Inheritance and Variation Important Questions
• Chapter 5 Molecular Genetics Important Questions
• Chapter 6 Evolution Important Questions
• Chapter 7 Human Health and Diseases Important Questions
• Chapter 8 Microbes in Human Welfare Important Questions
• Chapter 9 Applications of Biotechnology Important Questions
• Chapter 10 Organisms and Population Important Questions
• Chapter 11 Biodiversity and its Conservation Important Questions
• Chapter 12 Environmental Issues Important Questions

Students get through the TN Board 12th Bio Botany Important Questions Chapter 10 Economically Useful Plants and Entrepreneurial Botany which is useful for their exam preparation.

TN State Board 12th Bio Botany Important Questions Chapter 10 Economically Useful Plants and Entrepreneurial Botany

Very short answer questions

Question 1.
What is meant by pseudo-cereal?
Answer:
Pseudo cereal refers to the foods that are prepared and eaten as a whole grain but are from grasses. Eg. Quinoa.

Question 2.
Give the scientific names of two bowls of cereal.
Answer:

1. Paddy – Oryza sativa
2. Wheat – Triticum aestivum

Question 3.
Mention any two examples of minor millets.
Answer:

1. Foxtail millet – Setaria italica.
2. Kodo millet – Paspalum scorbiculatum.

Question 4.
Define Pulses.
Answer:
Pulses are the edible seeds that are harvested from the fruits of the Fabaceae family. They ‘provide a vital source of plant-based protein, vitamins, and minerals.

Question 5.
Mention the nativity of black gram and green gram.
Answer:

1. Black gram – India
2. Green gram – India.

Question 6.
Define sugar.
Answer:
Sugar refers to the generic name of sweet tasting soluble carbohydrate that is used in foods and beverages.

Question 7.
Mention any two uses of Palmyra.
Answer:

1. Palm sugar is prepared from the exudate from the inflorescence of Palmyra.
2. Germinated seeds have elongated embryos surrounded by fleshy scale leaf, which is edible.

Question 8.
Explain briefly the property of coffee.
Answer:
Coffee, a non-alcoholic beverage, contains an alkaloid that stimulates the central nervous system. It also possess milS diuretic property.

Question 9.
What is the queen of spices? Write the areas of its cultivation in India.
Answer:
The queen of spices is cardamom. It is cultivated in the Western Ghats and North-Eastern India.

Question 10.
What is meant by red pepper?
Answer:
The red pepper is otherwise called as chilies and used in the preparation of sauces, curry powder, and pickles. The active ingredient is capsaicin.

Question 11.
Mention any two properties of teak wood.
Answer:

1. The heartwood of teak is golden yellow to golden brown in color and changes into darker when exposed to light.
2. It is durable, as it is resistant to the attack of termites and fungi.

Question 12.
Who invented paper production?
Answer:
Paper production is a Chinese invention. They prepared paper from the inner bark of paper mulberry in 105 A.D.

Question 13.
What is folk medicine?
Answer:
Folk medicine refers to the system of medicine practiced by ethnic communities through oral communication without any written documents.

Question 14.
Name any two medicinal plants.
Answer:

1. Keezhanelli – Phyllanthus amarus
2. Nilavembu – Andrographis paniculata.

Question 15.
Define Entrepreneurial Botany.
Answer:
Entrepreneurial Botany is defined as the study of how new businesses are created using plant resources. Eg. the Timber industry, the Rubber industry, etc.

Short answer questions

Question 1.
Mention the uses of wheat.
Answer:

1. In the Northern part of India Wheat is the staple food.
2. Bread and other bakery products are produced from wheat flour.
3. Alcoholic beverages and nutritive drinks are made from malted wheat.

Question 2.
Distinguish between a black gram and green gram.
Answer:

Question 3.
What are the national fruits of India? Explain its varieties and uses.
Answer:
The national fruit of India is mango.
The major varieties of mango in India are Alphonsa, Banganapalli, Neelam, and Malkova.
Mango is rich in beta carotenes and forms major table fruit in India. Unripe mangoes are used in chutneys, pickles, side dishes, or maybe eaten raw with salt and chili. Jelly is made from mango pulp. The aerated or non-aerated soft drinks are produced from mango pulp.

Question 4.
Mention the origin and area of cultivation of sugar cane.
Answer:
Sugar cane, Saccharum officinarum is originated from New Guinea.
All districts of Tamil Nadu except Kanyakumari and Nilgiris cultivate sugar cane.

Question 5.
Write down the importance of groundnut.
Answer:
Brazil is the native of groundnut. The nuts contain 45% oil. Kernels are a rich source of phosphorous and vitamins.
It gives the premium cooking oil as it does not smoke. This oil is used in the manufacture of soaps and lubricants.

Question 6.
What is the king of spices? Mention its uses.
Answer:
The king of spices is black pepper, which is otherwise known as “Black Gold of India”. In the preparation of sauces, soups, curry powder, and pickles, it is used as a flavoring agent. It is also used in medicine as an aromatic stimulant for enhancing salivary and gastric secretions. Pepper enhances the bio-absorption of medicines.

Question 7.
List the various uses of rubber.
Answer:

1. 70% of the rubber is being consumed by tire and other automobile manufacturing companies.
2. Rubber is used in the manufacture of footwear, wire and cable insulations, raincoats, household and hospital goods, erasers, adhesives, and rubber bands. Concentrated latex is used for making gloves, balloons, and condoms. Cushion, pillows, and life belts are manufactured from foamed latex.

Question 8.
What is a psychoactive drug? Explain any one of such drugs.
Answer:
Psychoactive drug refers to a drug from some plants, which alters an individual’s perceptions of mind by producing hallucination.
One of the examples is cannabis or marijuana, the botanical name being Cannabis sativa. Marijuana is native of China and now it is legally cultivated in the states of Gujarat, Himachal Pradesh, Uttarkhand, Uttar Pradesh, and Madhya Pradesh of India as industrial hemp. The active principle, which possesses medicinal properties is trans- tetrahydro cannabinol (THC).

Long answer questions

Question 1.
Write down the attributes of cereals as food plants?
Answer:

1. Their greater adaptability and successful colonization on every type of habitat.
2. The relative ease of cultivation is another important quality of cereals.
3. They produce a higher yield per unit area due to their tillering property.
4. The grains can be easily handled because the grains are dry and compact. They can easily be transported and stored without spoilage.
5. They provide energy to the consumer due to their high calorific value.

Question 2.
Write about the importance of vegetables with examples.
Answer:
Vegetables are an important part of healthy eating. They provide many nutrients, including vitamins, potassium, fiber and folic acid. Vitamins A, E and C are abundant is vegetables.
One of the examples of a vegetable is okra, Abelmoschus esculantus. It is otherwise known as Lady’s finger, which is a native of tropical Africa. Lady’s finger is grown in Assam, Maharashtra, and Gujarat in large quantities. In Tamil Nadu, Coimbatore, Dharmapuri, and Vellore are the major districts, which cultivate okra.
The fresh and tender fruits are used as vegetables. It has the most important nutrients, especially phosphorous.

Question 3.
List out the uses of red chilies.
Answer:

1. Red chilies are crushed and powdered to use as condiments.
2. Chilies are used in the manufacture of sauces, curry powders, and preparation of pickles.
3. The active ingredient of chilies is capsaicin.
4. It has pain-relieving properties and used in pain-relieving balms.
5. Chillies are a good source of vitamins C, A, and E.

Question 4.
Write about the folk system of medicine.
Answer:
The rural communities of India are practicing this system of medicine through oral tradition without any authenticated written documents. Ministry of Environment and Forestry launched a program of All India Coordinated Research project on ethnobotany to document the plants used as medicine by ethenic groups in India. About 8000 plant species have been documented as the result of this project.
Irulas, Malayalis, Kurumbas, Paliyans, and Kannis are the tribal groups in Tamil Nadu, who are known for their medicinal knowledge. Some of the important medicinal plants they use include keezhanelli and nilavembu, which are now brought for medicinal use.

Choose the correct answers.

1. Match the following.

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
(c) (p)-(ni); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(b) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)

2. Match the following.

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

3. Match the following.

(a) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(a) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

4. Match the following.

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
(d) (p)-(ii); (q)-(i); fr)-(iv); (s)-(iii)
Answer:
(d) (p)-(ii); (q)-(i); fr)-(iv); (s)-(iii)

5. Which one is called as holy basil?
(a) Phyllanthus emblica
(b) Acalypha indica
(c) Ocimum sanctum
(d) Aegle marmelos
Answer:
(c) Ocimum sanctum

6. Marijuana is included under the family:
(a) Solanaceae
(b) Cannabiaceae
(c) Acanthaceae
(d) Euphorbiaceae
Answer:
(b) Cannabiaceae

7. Which of the following is used as Bio-pest repellent:
(a) Azadirachata indica
(b) Acalypha indica
(c) Vinca rosea
(d) Aegle marmelos
Answer:
(a) Azadirachata indica

8. Chenopodium quinoa is coming under:
(a) Pulses
(b) Cereals
(c) Nuts
(d) Pseudo-cereals
Answer:
(d) Pseudo-cereals

9. Choose the odd man out:
(a) Black gram
(b) Sorghum
(c) Pigeon gram
(d) Green gram
Answer:
(b) Sorghum

10. Choose the odd one:
(a) Coffea arabica
(b) Elettaria cardamomum
(c) Piper nigrum
(d) Cumcuma longa
Answer:
(a) Coffea arabica

11. Find out the odd one.
(a) Phyllanthin
(b) Azadictin
(c) Gibberillin
(d) Morphine
Answer:
(c) Gibberillin

12. Indicate the odd one.
(a) Nilavembu
(b) Garlic
(c) Indian gooseberry
(d) Vilvum
Answer:
(b) Garlic

13. Choose the correct one.

Answer:
(c)

14. Which of the following is not a correct pair?

Answer:
(d)

15. Which of the following is the correct pair?

Answer:
(b)

16. Choose the incorrect pair.

Answer:
(c)

17. Assertion: Phyllanthus is a well-known hepato protective plant used for the treatment of jaundice.
Reason: It has been scientifically proved that the extract of Pamarus is effective against hepatitis B virus.
(a) Both Assertion and Reason are correct, Assertion is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Assertion is not the correct explanation of Assertion.
(c) Assertion is not correct, Reason is correct.
(d) Assertion is correct, Reason is not correct.
(e) Both Assertion and Reason are not correct.
Answer:
(b) Both Assertion and Reason are correct, Assertion is not the correct explanation of Assertion.

18. Assertion: Medicinal plants play a significant role in providing healthcare services to urban people.
Reason: They serve as the therapeutic agents as well as important raw material for ’ the manufacture of traditional and modern medicines.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is not correct, Reason is correct.
(d) Assertion is correct, Reason is not correct.
(e) Both Assertion and Reason are not correct.
Answer:
(c) Assertion is not correct, Reason is correct.

19. Assertion: The essential oil from Jasmine is used in modern perfumery and cosmetics.
Reason: The aroma of Jasmine blends well with other perfumes.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is not correct, Reason is correct.
(d) Assertion is correct, Reason is not correct.
(e) Both Assertion and Reason are not correct.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

20. Assertion: An orange dye “Henna” is obtained from the roots of Law Sonia inermis.
Reason: The principal colouring matter lacosone obtained from the root is harmless.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is not correct, Reason is correct.
(d) Assertion is correct, Reason is not correct.
(e) Both Assertion and Reason are not correct.
Answer:
(e) Both Assertion and Reason are not correct.

21. Which of the following statement is not correct?
(a) Traditionally turmeric is used as skin care cosmetics in Tamil Nadu.
(b) Aloe vera is an antioxidant.
(c) Perfumes are manufactured from essential oil.
(d) All the above statement are not correct.
Answer:
(d) All the above statement are not correct.

22. Choose the correct statement.
(a) Black pepper is known as the queen of spices.
(b) Cardamom is called as the king of spices.
(c) Black pepper is called as the ‘black gold of India’.
(d) None of the above.
Answer:
(c) Black pepper is called as the ‘black gold of India’.

23. Indicate the incorrect statement.
(a) The origin of red mango is Southern Asia
(b) The origin of red gram is Southern Irtdia.
(c) Lady’s finger is a native of Tropical Africa.
(d) Kodo millet is originated from Asia.
Answer:
(d) Kodo millet is originated from Asia.

24. Identify the correct statement.
(a) Rice is the chief source of carbohydrate.
(b) Wheat is the chief sources of protein.
(c) Edible oil is extracted from the husks of paddy.
(d) Rice bran is used as a fuel.
Answer:
(a) Rice is the chief source of carbohydrate.

Students get through the TN Board 12th Bio Botany Important Questions Chapter 9 Plant Breeding which is useful for their exam preparation.

TN State Board 12th Bio Botany Important Questions Chapter 9 Plant Breeding

Very short answer questions

Question 1.
Define organic farming.
Answer:
Organic fanning is defined as an alternative agriculture system, that sustains the health of soils, ecosystem and people, using natural inputs like organic manure, bio-pesticides etc.

Question 2.
Mention any two advantage of biofertilizers.
Answer:

1. Biofertilizers are eco-friendly organic agro-inputs.
2. They are more efficient and cost-effective than chemical fertilizers.

Question 3.
Name any two free-living nitrogen-fixing bacteria:
Answer:

1. Azotobactor
2. Clostridium

Question 4.
What is the importance of root nodule?
Answer:
The root nodules are the place, where the nitrogen-fixing symbiotic bacteria, Rhizobium resides and converts the atmospheric nitrogen into a bioavailable form to the plants.

Question 5.
Define Arbuscular Mycorrhizae.
Answer:
Arbuscular mycorrhizae (AM) is defined as the symbiotic association between certain phycomycetous fungi and angiosperm roots.

Question 6.
Explain Bio-pesticides.
Answer:
Bio-pesticides are biologically based agents j used for the control of plant pests.

Question 7.
Name any two green manure crops.
Answer:

1. Crotalaria juncea
2. Indigofera tinctoria

Question 8.
Define plant breeding.
Answer:
Plant breeding refers to the science of improvement of crop varieties with a higher yield, better quality, resistance to diseases and shorter duration for yield.

Question 9.
Define Mutagenesis.
Answer:
Mutagenesis is defined as the process by which developing new genetic diversity by exposing crop plants to chemical agents or radiation.

Question 10.
Explain hybridization.
Answer:
Hybridization refers to the method of producing new crop varieties, in which two or more plants of varying genetic constitution 1 are crossed to produce a hybrid.

Question 11.
Define Pseudoheterosis.
Answer:
Pseudoheterosis is defined as a hybrid I possessing superiority over parents in vegetative growth, but not in yield and adaptation, usually sterile or poorly fertile.

Question 12.
What are polyploids?
Answer:
Polyploids are plants that possess more than two sets of chromosomes.

Question 13.
Define green revolution.
Answer:
The green revolution is defined as the cumulative result of a series of research, development, innovation and technology transfer initiatives j in order to increase crop production.

Question 14.
Explain Biofortification.
Answer:
Biofortification is referred to as a process by which crops with high levels of vitamins and minerals or high protein and healthier fats are produced.

Question 15.
Mention any two methods of New Plant Breeding Techniques (NBT).
Answer:
The two methods of New Plants Breeding Techniques are:

1. Genetic Engineering
2. Plants tissue culture

Short answer questions

Question 1.
Explain organic agriculture.
Answer:
An alternative type of agriculture in which the agro-inputs are natural and ecofriendly is known as agro farming. It is originated early in the twentieth century. It is an agricultural production system that sustains the health of the soils, ecosystems and people. It relies on natural ecological processes, biodiversity and cycles adapted to local conditions rather than the use of inputs with adverse effect.

Question 2.
What are the characteristics of biofertilizers?
Answer:

1. The biofertilizers are the preparations of living cells or latent cells of microorganisms.
2. They should help the plants uptake of nutrients by their interactions. Eg: Mycorrhiza.
3. Biofertilizers are eco-friendly, cost-effective and more efficient than chemical fertilizers.

Question 3.
What are the advantages of Arbuscular mycorrhizae (AM)?
Answer:

1. Arbuscular mycorrhizae are the process of the symbiotic association between phycomycetous fungi and angiosperm roots.
2. They have the ability to mobilise the phosphate found in the soil abundantly.
3. They also provide the necessary strength to resist diseases, germs and unfavourable weather conditions.

Question 4.
Distinguish between Mass selection and Pureline selection.
Answer:

Question 5.
Who coined the term mutation breeding? Write its advantages.
Answer:
The term “Mutation breeding” was coined by Muller and Stadler in 1927-28.
They have the advantage of improving the defect without losing an agronomic and quality character in agriculture and crop improvement. Gene mutations provide essential inputs for evolution as well as for recombination and selection. Seedless crops are developed by this method.

Question 6.
What are vegetables fortified with nutrients released by the Agricultural Research Institute?
Answer:

1. Vitamin A enriched carrot, spinach, pumpkin.
2. Vitamin C enriched bitter guard, bathua, mustard and tomato.
3. Iron and calcium-enriched spinach and bathura.
4. Protein-enriched beans, broad beans, lablab, French and garden peas.

Question 7.
List the plant’s resistance to insect pests developed through plant breeding.
Answer:

Long answer questions

Question 1.
Write about polyploids breeding.
Answer:
Polyploids are plants, that possess more than two sets of chromosomes. Diploids (2n) number of chromosomes are present in the majority of flowering plants. Polyploids often exhibit increased hybrid vigour by increasing heterozygosity Polyploidy increase the tolerance to both biotic and abiotic stresses. It offers a buffering effect of deleterious mutations. The production of seedless varieties is possible due to meiotic error, Polyploidy often results in reduced fertility and is considered to be a major force in the evolution of both wild and cultivated plants.
Autopolyploidy and Allopolyploids are the two types of polyploids.
Autopolyploidy: The doubling of the chromosome by themselves in the same plant is called autopolyploidy.
Eg: Triploid condition in sugar beets, apple and pear. In tomato, it leads to seedless variety. Polyploidy can be induced by a chemical called colchicine.
Allopolyploids: The multiplication of chromosome sets that are initially derived from two different species, is called allopolyploidy.
Eg: Triticale (Triticum durum X Secale cereal), Raphanobrassica (Brassica oleraceae X Raphanus satious).

Question 2.
List out the objectives of plant breeding.
Answer:
The followings are the objectives of plant breeding.

1. The increase in crop yield, plant vigour and increase in the fertility of the plant are the main objectives of plant breeding.
2. Raise plants with increased tolerance to environmental factors like salinity, temperature and drought.
3. To prevent the premature falling of buds, fruits etc.
4. The synchronous maturity of gametes should be improved.
5. To develop plants that develop resistance to pathogens and pests.
6. To develop photosensitive and thermosensitive varieties of plants

Question 3.
What are the changes that take place in a plant species due to domestication?
Answer:

1. They have to adapt to a greater diversity of environments and a wider geographical range.
2. They may have simultaneous uniform flowering and Suiting.
3. Lack of shattering or scattering of seeds.
4. They may have increased the size of fruits and seeds.
5. They have to change from a perennial to an annual habit.
6. Change in the breeding system.
7. They may change to increased yield.
8. Increased resistance to disease and pest.
9. Parthenocarpic seedless fruits may be developed.
10. Enhancing colour, appearance palatability and nutritional composition.

Question 4.
Draw the diagram showing the benefits of Am colonization and label.
Answer:

Question 5.
Liquid seawater fertilizer is not only organic but also eco-friendly. Justify.
Answer:
Seaweed liquid fertilizer (SLF) contains organic nutrients, like cytokinin, gibberellins and auxin. It also contains macro and micronutrients. Seaweed liquid fertilizer is made from kelp (brown algae), which contains alginate. This alginate reacts with metals in the soil and forms long, cross-linked polymers, which improve the crumbling of soil, swell up when they get wet. It retains moisture for a long time. They are especially useful in organic gardening, which provides carbohydrate for plants.
This manure has more than 70 minerals, vitamins and enzymes which promote vigorous growth in plants. The plants grown in seaweed liquid fertilizer have improved resistance to frost and disease, indicating that this fertilizer is ecofriendly-pesticide.

Choose the correct answer.

1. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

2. Match the following (Vavilov’s centres):

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
(d) (p)-(ii); (q)-(i); (r)-(iv);(s)-(iii)
Answer:
(c) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)

3. Match the following:

(a) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(a) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)

4. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(a) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

5. The method of creation of genetic variation includes:
(a) Mutation
(b) Hybridization
(c) Vegetative propagation
(d) Tissue culture
Answer:
(c) Vegetative propagation

6. Objective of plant breeding is:
(a) to increase yield
(b) to decrease tolerance to disease
(c) to increase sensitivity toi salinity
(d) to prevent synchronous maturity.
Answer:
(a) to increase yield

7. The introduction of foreign genes into DNA of a plant for the first time in the year:
(a) 1940
(b) 1985
(c) 1994
(d) 2000
Answer:
(c) 1994

8. Bacterial blight resistance was achieved in;
(a) Wheat
(b) Cowpea
(c) Chilli
(d) Cauliflower
Answer:
(b) Cowpea

9. Choose the odd man out.
(a) E.Borlaug
(b) M.S.Swaminathan
(c) Nel jayaraman
(d) N.G.P.Rao
Answer:
(c) Nel jayaraman

10. Find out the odd one out.
(a) Mutation
(b) Gene transfer
(c) Cytoplasmic fusion
(d) Polyploidy
Answer:
(c) Cytoplasmic fusion

11. Indicate the odd one out (Bio fortification)
(a) Protein content
(b) Fat content
(c) Vitamin content
(d) Gibberellin content
Answer:
(d) Gibberellin content

12. Choose the odd one out (NBT)
(a) Plant tissue culture
(b) Genetic Engineering
(c) Heterosis
(d) Somatic hybridization
Answer:
(c) Heterosis

13. Choose the correct pair.

Answer:
(a)

14. Choose the incorrect pair.

Answer:
(b)

15. Choose the correct pair.

Answer:
(b)

16. Choose the incorrect pair.

Answer:
(c)

17. Assertion: Organic agriculture is a production system that sustains the health of the soils, ecosystem and people.
Reason: Organic agriculture relies on ecological processes, biodiversity and cycles adapted to local conditions rather than the use of inputs with adverse effect.
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Assertion is not correct, Reason is correct.
(e) Both Assertion and Reason are not correct.
Answer:
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.

18. Assertion: Biofertilizers are eco-friendly agro-inputs.
Reason: They are cost-effective and efficient than chemical fertilizers.
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Assertion is not correct, Reason is correct
(e) Both Assertion and Reason are not correct.
Answer:
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

19. Assertion: Rhizobium is best suited for paddy fields, which increase yield by 15-40%.
Reason: This nitrogen-fixing bacterium when applied in soil undergoes multiplication in billions and fix nitrogen into a usable form for plants.
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Assertion is not correct, Reason is correct.
(e) Both Assertion and Reason are not correct.
Answer:
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.

20. Assertion: Trichoderma is symbiotic fungi, that are common in soil and root ecosystem.
Reason: They have been recognized as bio-control agent for plant disease.
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Assertion is not correct, Reason is correct.
(e) Both Assertion and Reason are not correct.
Answer:
(c) Assertion is correct, Reason is not correct.

21. Which of the following statement is correct?
(a) Most important green manure crops are Vinca rosea, Crotalaria and Thespecia.
(b) Most important green manure crops are Indigotera, Abitelon and Banian tree.
(c) Most important green manure crops are Crotalaria juncea, Tephrosia purpurea, and Indigofera tinctoria.
(d) None of the above.
Answer:
(c) Most important green manure crops are Crotalaria juncea, Tephrosia purpurea, and Indigofera tinctoria.

22. Choose the incorrect statement.
(a) The aim of plant breeding is to increase yield.
(b) The aim of plant breeding is to increase the fertility of crop.
(c) The aim of plant breeding is to increase tolerance to environmental conditions.
(d) All the above statements are not correct.
Answer:
(d) All the above statements are not correct.

23. Find out the correct statement.
(a) William S. Gaud coined the term mutation breeding.
(b) Muller and Stadler coined the term green revolution.
(c) M.S.Swaminathan is a pioneer mutation breeder.
(d) Nel Jayaraman hails from Andhra Pradesh.
Answer:
(c) M.S.Swaminathan is a pioneer mutation breeder.

24. Indicate the incorrect statement.
(a) Wheat variety Atlas 66 have high protein content.
(b) Wheat variety Atlas 66 have less protein content.
(c) Wheat variety Atlas 66 have been used as a donor for improving cultivated wheat.
(d) None of the above.
Answer:
(b) Wheat variety Atlas 66 have less protein content.

Students get through the TN Board 12th Bio Botany Important Questions Chapter 8 Environmental Issues which is useful for their exam preparation.

TN State Board 12th Bio Botany Important Questions Chapter 8 Environmental Issues

Very short answer questions

Question 1.
Define the greenhouse effect.
Answer:
The greenhouse effect is defined as a process by which the radiant heat from the sun is captured by gases in the atmosphere, leading to an increase in atmospheric temperature.

Question 2.
Define global warming.
Answer:
Global warming is a process through which the mean global temperature increases due to the increased concentration of greenhouse gases.

Question 3.
Mention any two natural sources of methane in the atmosphere.
Answer:

1. Paddy fields
2. Bacterial action in water bodies.

Question 4.
Expand CDM.
Answer:
CDM means Clean Development Mechanism.

Question 5.
Mention any two plants which can indicate SO2 pollution.
Answer:

1. Ficus
2. Pinus

Question 6.
What do you mean by social forestry?
Answer:
Social forestry refers to the management of forest and afforestation on barren lands with the purpose of helping the environmental, social, and rural development and benefits.

Question 7.
Mention any two causes of Deforestation.
Answer:

1. Agriculture plantation and livestock ranching are one of the main causes of deforestation.
2. Disproportionate felling of trees for timber.

Question 8.
Define Alien species.
Answer:
Alien species is defined as a non-native species to the ecosystem on the country, which poses a serious threat to the native species and ecosystem.

Question 9.
Name any two invasive plant species in India.
Answer:
The invasive plant species are:

1. Prosopis juliflora
2. Eichhornia crassipes.

Question 10.
Define Endemic species.
Answer:
Endemic species are defined as plants or animals that exist only in one geographic region.

Question 11.
Define carbon sequestration.
Answer:
Carbon sequestration is defined as a process through which capturing and storing of carbon-di-oxide in the atmosphere take place.

Question 12.
What is Biochar?
Answer:
Biochar is a long-term method to increase the ability of plants to store more carbon.

Question 13.
Expand EIA.
Answer:
EIA means Environmental Impact Assessment.

Short answer questions

Question 1.
Explain briefly about remote sensing.
Answer:
Remote sensing is the acquisition of information about an object without making physical contact with the object by measuring its reflected and emitted radiation at a distance from the target area. It gives exact pictures and data on the identification of even a single tree in a large area of vegetation and wildlife. It is also helpful in the identification of biodiversity-rich or fewer areas for futuristic works on conservation and restoration of biota. It helps in the maintenances of various species including commercial crops, medicinal plants, and threatened plants.

Question 2.
What is biomonitoring? Explain it briefly.
Answer:
Biomonitoring is the act of observing and assessing the current state and changes in the ecosystem, biodiversity components, landscape including natural habitat, population, and species. Eg: In an agricultural drone, a bird’s eye view of a farmer can reveal many issues like irrigation problems, soil variation, and pests as well as fungal infestation. It is used in farming in order to help increased crop production and monitor crop growth. It is also helpful for a cost-effective safe methods of spraying pesticides and fertilizer.

Question 3.
Invasion of alien species disrupts ecosystem processes. Justify.
Answer:
The alien species disrupt ecosystem processes, because

1. They threaten biodiversity, reduce native herbs, reducing ecosystem services (benefits).
2. They only alter the ecosystem and micro intimate by prolific spreading.
3. They also alter the nature of the soil and make it unsuitable for native species.
4. They create human health problems like allergies.
5. Thus they degrade the local environment and eliminate important local species.

Question 4.
Mention any three achievements of the Afforestation project.
Answer:

1. Degraded forests were restored.
2. Environmental and ecological stability was maintained.
3. Afforestation was helpful to conserve bio-diversity, wildlife, and genetic resources.

Question 5.
Distinguish between Agroforestry and social forestry.
Answer:

Question 6.
Mention any three major activities of forestry extension centers.
Answer:

1. Imparting training to the public on tree growing methods.
2. Publicity and propaganda of the advantage of tree growing,
3. Raising the seedlings of important tree species and supply to the public with subsidies.

Question 7.
Write down any three effects of- global warming on plants.
Answer:

1. Global warming leads to low agricultural productivity.
2. Weeds, pests, and fungi which need warmer temperature, will increase in number due to global warming.
3. Global warming may change the flowering seasons and pollinators.

Question 8.
Mention any three causes of greenhouse gas emission.
Answer:

1. Agriculture practices and animal husbandry practices lead to the emission of CH₄.
2. CO₂ and CH₄, are produced by burning fossil fuels.
3. The household items like electrical gadgets including refrigerators and air conditioners release chlorofluorocarbon.

Long answer questions

Question 1.
List the objectives of Afforestation:
Answer:

1. One of the prime objectives of Afforestation is to increase forest cover by planting more trees, which increases O₂ production and air quality.
2. Rehabilitation of degraded forests to increase CO₂ fixation, leading to reduction of atmospheric carbon dioxide.
3. Medicinal plants are planted in mixed plantations and produce natural medicines.
4. Regeneration of indigenous herbs and shrubs.
5. The other objectives include the increase of availability of water table or groundwater, reduction of nitrogen leaching from the soil, and reduction of nitrogen contamination of drinking water.

Question 2.
List the plants used as plant indicators of pollutions.
Answer:

Question 3.
Distinguish between in-situ and ex-situ conservation.
Answer:

Question 4.
Write about Biodiversity impact Assessment. How will you assess the impact?
Answer:
Biodiversity Impact Assessment (BIA) can be defined as a decision-supporting tool to help the development considering bio-diversity as an inclusive component followed by planning and implementation.
It integrates biodiversity consideration for developmental proposals.
They are legally bound mechanisms for implementing the conservation of biodiversity resources. They also provide fair and equitable sharing of the benefits arising from the use of bio-diversity.
The Bio-diversity impacts can be assessed by:

1. Change in land use and cover.
2. Fragmentation and isolation.
3. Extraction.
4. External inputs such as emissions, effluents, and chemicals.
5. Introduction of invasive, alien, or genetically modified species.
6. Impact on endemic and threatened flora and fauna.

Question 5.
List the importance of GIS.
Answer:

1. GIS is used in Environmental Impact Assessment.
2. It is also helpful in disaster management.
3. It is used in the zoning of landslide hazards.
4. It helps in the determination of land cover and land use.
5. It is used to determine flood damage.
6. It is used in the management of natural resources.
7. Soil mapping and wetland mapping can be done using GIS.
8. Identification of volcanic hazards and irrigation management can be carried out by this information.
9. It helps to study vegetation and to map threatened and endangered species.

Activity

Students may form ‘ECOGROUPS’ and discuss eco-issues of their premises and find solutions to the existing problems like litter disposal, water stagnation, health, and hygiene, greening the campus, and its maintenance.
Eco groups discussion topics:

1. Litter disposal: The litter forms solid waste which includes degradable and non-degradable waste. The degradable waste can be degraded to manure using bacteria and earthworms. Non- degradable waste like plastic can be recycled.
2. Water stagnation: Solution: Setting up of water harvesting system will solve water stagnation.
3. Health and hygiene: Solution: Keep the surroundings clean and neat. Follow personal hygiene strictly. Create awareness among the public.
4. Greening the campus: Solution: A tree planting programme may be initiated in the campus. Each member of Eco groups may be given responsibility for maintaining one or two trees in the campus.

Multiple choice questions

1. Match the following.

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
Answer:
(b) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)

2. Match the following.

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(c) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)

3. Match the following.

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

4. Match the following.

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)

5. Choose the odd man out.
(a) Sudhir kumar Sopary.
(b) Jadav molai Payeng
(c) Panduranga Hegde
(d) Swaminathan
Answer:
(d) Swaminathan

6. Find out the odd one.
(a) Western ghat
(b) National park
(c) Gulf of mannar
(d) Agasthiar malai
Answer:
(c) Gulf of mannar

7. Indicate the odd one (Ex-situ conservation)
(a) Pollen
(b) Seed
(c) Seedling
(d) Leaf
Answer:
(d) Leaf

8. Choose the odd one:
(a) Carbon-di-oxide
(b) Ammonia
(c) Methane
(d) Nitrous oxide
Answer:
(b) Ammonia

9. Choose the incorrect pair.

Answer:
(c)

10. Choose the incorrect pair?

Answer:
(d)

11. Which of the following is a correct pair?

Answer:
(a)

12. Choose the incorrect pair:

Answer:
(c)

13. Find out the plant indicator. depletion.
(a) Water Lilly
(b) Coconut
(c) Acacia sp
(d) Gladiolus
Answer:
(d) Gladiolus

14. Ozone depletion in the atmosphere results in:
(a) UV radiation
(b) CO₂ emission
(c) Nitrogen depletion
(d) Afforestation
Answer:
(a) UV radiation

15. Which of the following is a hedge plant.
(a) Azadirachta indica
(b) Acacia spp
(c) Teak
(d) Eucalyptus
Answer:
(b) Acacia spp

16. Alien invasive species include.
(a) Casuarina
(b) Amelia dubia correct.
(c) Prosopis juliflora
(d) Bamboo
Answer:
(c) Prosopis juliflora

17. Assertion: Majority of endemic species are threatened.
Reason: Because of their narrow specific habitat, reduced seed production low dispersal rate, less viable nature and human interference.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Both Assertion and Reason are not correct.
(e) Assertion is not correct, Reason is correct.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

18. Assertion: Eichhornia crassipes increases the oxygen content of water bodies.
Reason: Anoxic condition in water bodies leads to Eutrophication.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Both Assertion and Reason are not correct.
(e) Assertion is not correct, Reason is correct.
Answer:
(e) Assertion is not correct, Reason is correct.

19. Assertion: In plants, photosynthetic chemicals will be affected due to ozone depletion.
Reason: Decreased photosynthesis will result in increased atmospheric CO₂, resulting in global warming.
(a) Both Assertion and R are correct, R is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Both Assertion, and Reason are not correct.
(e) Assertion is not correct, Reason is correct.
Answer:
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

20. Assertion: In Agroforestry, nutrient cycling between species improves and organic matter in the soil is maintained.
Reason: Because of the absence, of microorganisms, insects, and earthworm in the soil.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are Correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct
(d) Both Assertion and Reason are not correct.
(e) Assertion is not correct, Reason is correct.
Answer:
(c) Assertion is correct, Reason is not correct

21. Which of the following statement is correct?
(a) Trees provide microclimate for crops.
(b) They disturb O₂-CO₂ balance.
(c) Trees increase atmospheric CO₂.
(d) Trees cause decrease in relative humidity in atmosphere.
Answer:
(a) Trees provide microclimate for crops.

22. Choose the incorrect statement.
(a) Ozone depletion increases the incidence of cataract in human.
(b) It also causes lung irritation.
(c) Ozone depletion enhances the functioning of immune system.
(d) It increases the incidence of mutation:
Answer:
(c) Ozone depletion enhances the functioning of immune system.

23. Find out the correct statement.
(a) Prosophis juliflora is a native species found in Tamil Nadu.
(b) It is an aggressive coloniser.
(c) It is an invasive species native of South Africa.
(d) None of the above.
Answer:
(b) It is an aggressive coloniser.

24. Indicate the incorrect statement.
(a) Hardwickia binata is an endemic tree.
(b) It is endemic to peninsular and northern India.
(c) It is endemic to Kerala and Tamil Nadu.
(d) None of above.
Answer:
(c) It is endemic to Kerala and Tamil Nadu.