Category: Important Questions

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

Chemistry NEET MCQ

TN State Board 12th Chemistry Important Questions and Answers

• Chapter 1 Metallurgy Important Questions
• Chapter 2 p-Block Elements – I Important Questions
• Chapter 3 p-Block Elements – II Important Questions
• Chapter 4 Transition and Inner Transition Elements Important Questions
• Chapter 5 Coordination Chemistry Important Questions
• Chapter 6 Solid State Important Questions
• Chapter 7 Chemical Kinetics Important Questions
• Chapter 8 Ionic Equilibrium Important Questions
• Chapter 9 Electro Chemistry Important Questions
• Chapter 10 Surface Chemistry Important Questions
• Chapter 11 Hydroxy Compounds and Ethers Important Questions
• Chapter 12 Carbonyl Compounds and Carboxylic Acids Important Questions
• Chapter 13 Organic Nitrogen Compounds Important Questions
• Chapter 14 Biomolecules Important Questions
• Chapter 15 Chemistry in Everyday Life Important Questions

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

TN State Board 12th Bio Zoology Important Questions Chapter 12 Environmental Issues

Very short answer questions

Question 1.
Define Pollution.
Answer:
Pollution is defined as any undesirable change in the physical, chemical, and biological characteristics of an environment.

Question 2.
What are pollutants?
Answer:
Pollutants are the agents which cause pollution.

Question 3.
What are the different basic groups of pollutants?
Answer:
The pollutants are classified into two major groups namely Non-degradable and degradable pollutants.

Question 4.
Name the main sources of carbon monoxide pollution.
Answer:
The main sources of carbon monoxide pollution include Automobile exhausts, fumes from factories and the burning of firewood.

Question 5.
Define SMOG.
Answer:
SMOG is defined as a type of air pollution caused by tiny particles in the air.

Question 6.
Mention any two cost-effective treatments of air pollution?
Answer:
The cost-effective treatment of air pollution includes:

1. Growing indoor plants and
2. Using high-performance biofilters.

Question 7.
Explain Air Quality Index (AQI).
Answer:
Air Quality Index is the number used by Government agencies to communicate to the public how polluted the air is at a given time.

Question 8.
Name any two examples of the non-point sources of pollutants.
Answer:

1. Agriculture chemical run-off.
2. Dumping of plastics in water bodies.

Question 9.
Define Noise pollution.
Answer:
Noise pollution is defined as the sound that is unwanted and undesirable or can disrupt one’s quality of life.

Question 10.
Name the chemicals present in mosquito repellents.
Answer:
The chemicals present in mosquito repellents are:

1. DEET (n-n-diethylenetatoluamide)
2. Alletrin

Question 11.
Define Biomagnification.
Answer:
Biomagnification is the process in which a non-degradable substance, that enters die – food chain does not get metabolized and instead gets transferred up the tropic levels of the food chain with the magnified level of that substance.

Question 12.
What is ‘4R’?
Answer:
‘4R’ means Refuse, Reduce, Reuse and Recycle. These are the mantra for remedy II for the plastic waste problem.

Short answer questions

Question 1.
What are plastics? Explain their sources.
Answer:
Plastics are low molecular weight organic polymers, that are not degradable in the natural environment.
The main sources of this plastic include:

1. The packaging material used in supermarkets.
2. Packing material in retail outlets.
3. Manufacturing industries.
4. Households, hotels, hospitals, and restaurants, and transport companies.
5. In municipal solid waste, plastic waste constitutes a major part.

Question 2.
Recycling and disposal of e-waste involve significant risk – Justify.
Answer:
The recycling and disposal of e-waste may involve risks to the health of workers and communities in developed countries.

1. Great care must be taken to avoid unsafe exposure in recycling operations.
2. The leading of materials like heavy metals from landfills and incinerator ashes may cause health problems to humans and animals.

Question 3.
How does water pollution affect on the ecosystem?
Answer:
Water pollution generally affects the aquatic ecosystems in the following ways:

1. It affects existing riches and habitats.
2. It affects the survival of organisms.
3. In certain cases, soil fertility is affected, leading to the state of uninhabitable.
4. It results in Eutrophication.

Question 4.
What are three sources of water pollution?
Answer:
The three sources of water pollution are:

1. Municipal waste
2. Industrial waste
3. Agricultural waste

Question 5.
Water pollution disrupts the nature of food chains as well as food webs – Justify.
Answer:

1. Pollutants such as lead and cadmium are taken up by primary consumers, where they can be lethal or get accumulated.
2. When these animals are consumed by secondary consumers, their pollutants are get enhanced by a process called biomagnification.
3. The food chain may get disrupted at any trophic level due to the magnification and accumulation of these chemicals.

Question 6.
Explain the Government Act and regulations to prevent water pollution.
Answer:

1. Water Act, 1974, section 17- 40 – Prohibits the pollution of a stream or well by disposal of polluting matter.
2. The Central / State pollution control Boards – They have the power to advise the central / state governments on various matters concerned with the prevention and. control of pollution of water.
3. The Ministry of Environment, forest and climate change (MoEFCC) is the nodal agency of the central government for planning, promotion, coordination, and overseeing the implementation of India’s environmental and forestry policies and programs.

Question 7.
How do you control ozone layer depletion?
Answer:

1. Phase down or ban the use of CFCs (CFC-free refrigerants).
2. The usage of chemicals such as halons and halocarbons ought to be minimized.
3. Creating awareness about ozone-depleting agents.

Long answer questions

Question 1.
Give an account of medical waste.
Answer:
Medical waste refers to any waste that contains infectious material generated by hospitals, medical research centers, laboratories, pharmaceutical companies, and veterinary clinics.
Medical’wastes constitute fluid like blood, urine, body parts, and other contaminants. They also include used syringes and needles, culture dishes, glasswares, bandages gloves, scalpels, swabs, and tissues.
Hie social and legal responsibilities of – people working in health care centers are the safe disposal of medical waste.
The disposal methods include incineration, chemical disinfection, autoclaving, encapsulation microwave irradiation. Landfill and burying inside premises as per norms are the final disposal of these wastes.

Question 2.
Describe the prevention methods of water pollution.
Answer:
The followings are the prevention strategies of water pollution:

1. Regulate or control pollutant discharge at the point of generation.
2. Treatment of wastewater by scientific methods before discharge into municipal treatment sources.
3. Setting up of Sewage Treatment Plants (STP) and Effluent Treatment Plants (ETP) where ever needed.
4. Regulate or restrict the use of chemical fertilizers and pesticides in agriculture. Create public awareness and involve people in the action plan.

Question 3.
Enumerate the effects of noise pollution.
Answer:
A link between noise and the health of humans and other organisms was established by USEPA (the United States Environmental Protection Agency). The noise pollution effects are:

1. It causes increased stress and tension nervousness, irritability anxiety depression, and panic attacks.
2. It also causes peptic ulcers, severe headaches, memory loss.
3. Noise pollution from offshore activities and poor activities affects marine animals.
4. Noise from firecrackers frightens animals and birds.
5. In humans, heart disease, high blood pressure, stress-related illness, sleep disruption, hearing loss, and productivity loss are some of the problems related to noise pollution.

Question 4.
Explain the causes and effects of ozone layer depletion.
Answer:
Causes:

1. Anthropogenic activities mainly cause ozone layer depletion.
2. Chlorofluorocarbons (CFCs) is the main cause of ozone layer depletion by releasing excess chlorine and bromine. Other ozone-depleting substances are hydrobromic fluorocarbons and methyl bromide.

Effects:

1. It allows UY rays to penetrate into the atmosphere, resulting in premature aging of skin and wrinkling of the skin.
2. It may cause suppression of the immune system.
3. It causes skin cancer (melanoma) and chronic effects leading to eye damage.
4. The free radicals and reactive oxygen and photons can damage DNA itself.

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)-(ii); (s)-(i)
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)-(ii); (q)-0); (r)-(iv); (s)-(iii)
(c) (p)-(iii); (q)-(iv); (r)-(ii);(s)-(i)
(d) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
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)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
(d) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
Answer:
(a) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)

4. Match the following:

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

5. Medical waste is classified under:
(a) Solid waste
(b) Organic waste
(c) Hazardous waste
(d) Chemical waste
Answer:
(c) Hazardous waste

6. Which of the following is an anaerobic ‘ process?
(a) Vermicomposting
(b) Biogas generation
(c) Segregation
(d) Nitrification
Answer:
(b) Biogas generation

7. How much garbage is collected per day from Chennai city?
(a) 5400 MT
(b) 4800 MT
(c) 2400 MT
(d) 6800 MT
Answer:
(a) 5400 MT

8. The method not used in the physical methods of waste treatment.
(a) Flotation
(b) Chlorination
(c) Sedimentation
(d) Filteration
Answer:
(b) Chlorination

9. Choose the odd man out:
(a) Nammalvar
(b) Sultan Md. Ismail
(c) Thiagarajan
(d) Jadav Payeng
Answer:
(c) Thiagarajan

10. Identify the odd one:
(a) Food waste
(b) Paper waste
(c) Plastic waste
(d) Organic waste
Answer:
(c) Plastic waste

11. Choose the odd one:
(a) Dilute and disperse
(b) Segregation and treatment
(c) Delay and decay
(d) Concentrate and confine
Answer:
(a) Dilute and disperse

12. Find out the odd one:
(a) Bandages
(b) Sealpels
(c) Glasswares
(d) Swabs and tissues
Answer:
(b) Sealpels

13. Which of the following is a correct pair?

Answer:
(c)

14. Choose the incorrect pair:

Answer:
(d)

15. Find out the correct pair:

Answer:
(a)

16. Indicate the incorrect pair:

Answer:
(c)

17. Assertion: Organic farming creates an eco-friendly pollution-free environment.
Reason: In organic farming, only natural and organic agro-inputs are used.
(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) Assertion is not correct, Reason is correct.
(e) Both Assertion and Reason are not correct.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

18. Assertion: DDT concentration is more in fish-eating birds than the actual concentration of the aquatic system.
Reason: This is due to a phenomenon called Biomagnification.
(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) Assertion is not correct, Reason is correct.
(e) Both Assertion and Reason are not correct.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

19. Assertion: The permissible limit of noise in commercial areas is 65 decibels during the day and 45 decibels during the night.
Reason: The threshold pain of noise pollution is 120 decibels.
(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) Assertion is not correct, Reason is correct.
(e) Both Assertion and Reason are not correct.
Answer:
(d) Assertion is not correct, Reason is correct.

20. Assertion: Acid rain is caused by Sulphur dioxide and nitric oxide.
Reason: During rain, the precipitation contains acidic components such as sulphuric acid or nitric acid.
(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) Assertion is not correct, Reason correct.
(e) Both Assertion and Reason are not correct.
Answer:
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

21. Which of the following statement is correct?
(a) Thinning of the stratospheric ozone layer is caused by all GHGs.
(b) Thinning of the stratospheric ozone layer is caused by CO₂ emission.
(c) Thinning of the stratospheric ozone layer is caused by Cf Cs.
(d) None of the above.
Answer:
(a) Thinning of the stratospheric ozone layer is caused by all GHGs.

22. Choose the incorrect statement:
(a) Trees are the best remedy for urban particulate matter.
(b) Forests act as sink for CO₂.
(c) Forests act as lungs of planet.
(d) All the above statements are not correct.
Answer:
(d) All the above statements are not correct.

23. Indicate the correct statement:
(a) Noise pollution can cause severe stomach ache.
(b) The threshold pain of noise pollution is about 120 decibels.
(c) Marine animals are not affected by noise pollution.
(d) None of the above.
Answer:
(b) The threshold pain of noise pollution is about 120 decibels.

24. Choose the incorrect statement:
(a) Limit generation is the most important consideration in managing radioactive wastes.
(b) Dilution and dispersion are adopted for wastes having high radioactivity.
(c) Much of the radioactivity in nuclear reactors and accelerator is very short-lived.
(d) Concentrate and confine process is another method of radioactive material disposal.
Answer:
(b) Dilution and dispersion are adopted for wastes having high radioactivity.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 11 Biodiversity and its Conservation which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 11 Biodiversity and its Conservation

Very short answer questions

Question 1.
Define Biodiversity.
Answer:
Biodiversity is defined as the assemblage of different life forms on Earth.

Question 2.
What is genetic diversity?
Answer:
Genetic diversity refers to the difference in genetic makeup between distinct species, within a single species, and between different populations.

Question 3.
Name any two ecosystem services.
Answer:

1. Providing food to many organisms.
2. Ecotourism.

Question 4.
What is the indicator of the health of an ecosystem?
Answer:
Endemism is the crucial indicator of the health of an ecosystem.

Question 5.
In South-East Asia, the dwindling of fruit bats is followed by a reduction in local fruit production. Why?
Answer:
The local fruit production in south-East Asia has got affected as the bats are found to be the pollinators of fruit trees.

Question 6.
Name any two animals found in the Deccan peninsula.
Answer:

1. Sambhar
2. Elephant

Question 7.
What are alien species?
Answer:
Alien species are organisms often introduced in a habitat unintentionally or deliberately for commercial purposes or a biological control agent and other uses.

Question 8.
What is the main effect of climate change?
Answer:
Climate change increases land and ocean temperature changes precipitation patterns and raises the sea level.

Question 9.
Name any two alien species introduced in India.
Answer:
The alien species introduced in India include Tilapia, Oreochromis mossambicus and Amazon sailfin catfish.

Question 10.
Define Endangered Species.
Answer:
Endangered species are defined as species that are very likely to be extinct in near future.

Question 11.
Expand IUCN.
Answer:
IUCN means International Union for Conservation of Nature.

Question 12.
Name any two national tiger reserves.
Answer:

1. Jim Corbett National park.
2. Kalakkad – Mundamthurai tiger reserve.

Short answer questions

Question 1.
What are sacred groves?
Answer:
Sacred groves of sacred woods are any assemblages of trees that are of special importance to a particular religion or culture. Sacred groves are seen in various cultures throughout the world. It is considered as one of the means of in situ conservation of plants and their associated organisms.

Question 2.
What are the advantages of gene banks? Gene banks are a type of biorepository, which collect and store genetic materials. The advantages of gene banks are as follows.
Answer:

1. The seeds of different genetic strains of commercially important plants can be stored for long periods in the seed bank.
2. Using the cryopreservation technique, the gametes of threatened species can be preserved in viable and fertile conditions.
3. Endangered species can be revived.

Question 3.
Write briefly about the principles of the Stockholm Declaration, 1972.
Answer:
The Stockholm convention in 1972 declared that the natural resources of Earth such as air, water, land, flora, and fauna of the natural ecosystems must be protected for the benefit of present and future generations. This should be done through careful planning, appropriate management, and judicial execution.

Question 4.
Name any three National parks in Tamil Nadu, their year, and place of establishment.
Answer:

Question 5.
List out any three important roles of IUCN.
Answer:

1. It influences, assists and encourages societies in the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable.
2. It influences Governments and industries through partnerships by providing information and advice.
3. It helps in the implementation of several international conventions on nature conservation and biodiversity.

Question 6.
Explain Coextinction with an example.
Answer:
Coextinction of a species is the loss of a species as a consequence of the extinction of another species.
Eg: Orchid bees and forest trees by cross-pollination. When the bees become extinct, the cross-pollination will not take place in forest trees and tree populations may also slowly become extinct.

Long answer questions

Question 1.
The richness of biodiversity in tropics is more. Justify.
Answer:
The reasons for the richness of biodiversity in the tropics are:

1. The warm tropical region on either side of the equator provides congenial habitat for living organisms.
2. Environmental conditions in the tropics are conducive for speciation as well as for supporting both variety and number of organisms.
3. The temperature in the tropic ranges between 25°C and 35°C, which are ideal for most of the metabolic activities of organisms.
4. The average rainfall is more than 200 mm per year, which is sufficient to support the whole ecosystem.
5. Rich resource and nutrient availability to support the functions of the ecosystem.
6. Climate, seasons, temperature, humidity, photoperiod etc., are more or less stable and encourage both variety and number.

Question 2.
List out the Biogeographical regions of India with their fauna.
Answer:

Question 3.
Pollutants and pollution are a major cause for biodiversity loss – Justify.
Answer:

1. The excessive use of fertilizers, pesticides, and heavy metals has polluted the land, ground, and surface water bodies.
2. There is a decline in the population of fish-eating birds and falcons due to pesticide biomagnification, which results in high concentrations of such pesticides in higher tropic levels like fishes.
3. Eutrophication of water bodies has resulted from the runoff from fertilizer-rich fields.
4. Metal contamination like mercury arsenic, cadmium, and chromium have to lead to the depletion of biotic resources in vulnerable ecosystems.
5. The veterinary medicine, Diclofenac used for the thinning of eggshells is said to be responsible for the death of the vulture population.

Question 4.
Explain the species-area relationship with the help of a diagram?
Answer:
The relationship between species richness and area for a wide variety of taxa (plants, birds, bats, freshwater fishes) will be a rectangular hyperbola in an arithmetic graph.
On a logarithmic scale, the relationship is a straight line described by the equation:
Log S = Log C + Z log A
where
S = Species richness
A = Area
Z = Slope of the line
C = Y-intercept .

Generally the regression coefficients or the slope value of the curve, Z has a value of 0.1- 0.2 regardless of taxonomic group or region. If the area is more like the entire continent, the curve will be steeper, the Z value being 0.6 – 1.2

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

5. Sunda lands include:
(a) Himalaya
(b) Nicobar islands
(c) Andaman
(d) Srilanka
Answer:
(b) Nicobar islands

6. The year of establishment of Mudumalai NP is:
(a) 1976
(b) 1980
(c) 1990
(d) 1989
Answer:
(c) 1990

7. Biosphere reserve in India includes:
(a) Gulf of Mannar
(b) Madras Crocodile Bank
(c) Guindy National park
(d) National tiger project
Answer:
(a) Gulf of Mannar

8. The UN Earth summit, which defined Biodiversity, was held in the year:
(a) 1990
(b) 1992
(c) 1982
(d) 1996
Answer:
(b) 1992

9. Choose the odd man out:
(a) Walter Rosen
(b) Alexander Rom Humboldt
(c) Charles Darwin
(d) Edward Wilson
Answer:
(c) Charles Darwin

10. Find out the odd one:
(a) Oryza sativa
(b) mango
(c) wheat
(d) Rouwolfia vomitaria
Answer:
(d) Rouwolfia vomitaria

11. Indicate the odd one out:
(a) the Western Ghats
(b) Gulf of Mannar
(c) the Himalayas
(d) Gangetic plain
Answer:
(b) Gulf of Mannar

12. Choose the odd one out:
(a) Habitat lose
(b) Pollution
(c) Population control
(d) Overexploitation
Answer:
(c) Population control

13. Which of the following is the correct pair?

Answer:
(d)

14. Choose the incorrect pair:

Answer:
(b)

15. Find out the correct pair:

Answer:
(a)

16. Which of the following is an incorrect pair?

Answer:
(d)

17. Assertion and reason:
Assertion: Biodiversity is very important and worthy to protection.
Reason: Because it provides sustainable benefits for the present as well as future generations.
(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) Assertion is not correct, reason is correct.
(e) Both assertion and reason are not correct.
Answer:
(a) Both assertion and reason are correct, reason is the correct explanation of assertion.

18. Assertion: Gene bank is a type of biorepository of genetic materials.
Reason: The genetic materials can be retrieved to revive endangered/threatened species.
(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) Assertion is not correct, reason is correct.
(e) Both assertion and reason are not correct.
Answer:
(a) Both assertion and reason are correct, reason is the correct explanation of assertion.

19. Assertion: Biodiversity supplies a large number of goods and services that sustain human life.
Reason: It supplies food, fuel, and building materials.
(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) Assertion is not correct, reason is correct.
(e) Both assertion and reason are not correct.
Answer:
(b) Both assertion and reason are correct, reason is not the correct explanation of assertion.

20. Assertion: Arignar Anna Zoological Park at Vandalur is the place of in-situ conservation of animals.
Reason: The Zoo has many attractive features like a Butterfly park, Aviary, Lion and deer safari, forest museum, etc.
(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) Assertion is not correct, reason is correct.
(e) Both assertion and reason are not correct.
Answer:
(d) Assertion is not correct, reason is correct.

21. Which of the following statement is correct?
(a) Ex-situ conservation is the conservation of a species in places of their natural homes.
(b) Ex-situ conservation is the conservation of species in Botanical gardens.
(c) Ex-situ conservation is the conservation of animals/plants in places outside their natural homes.
(d) None of the above
Answer:
(c) Ex-situ conservation is the conservation of animals/plants in places outside their natural homes.

22. Choose the incorrect statement:
(a) Biodiversity is the variety of all life on Earth.
(b) To date, about one million species have been identified on Earth.
(c) Sacred groves feature in various cultures throughout the world.
(d) None of the above.
Answer:
(b) To date, about one million species have been identified on Earth.

23. Identify the correct statement:
(a) Pollution is the only major cause of biodiversity loss.
(b) Species have been evolving and dying out ever since the origin of life.
(c) Nowadays, the species are becoming extinct at a slower rate.
(d) All the above statements are correct.
Answer:
(b) Species have been evolving and dying out ever since the origin of life.

24. Find out the incorrect statement:
(a) The term biodiversity was first introduced by Edward Wilson.
(b) The term biodiversity was first coined by Walter Rosen.
(c) The term biodiversity was popularised by Edward Wilson.
(d) None of the above.
Answer:
(a) The term biodiversity was first introduced by Edward Wilson.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 10 Organisms and Population which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 10 Organisms and Population

Very short answer questions

Question 1.
Define Ecosphere.
Answer:
Ecosphere is defined as the largest and nearly self-sufficient biological system which includes all the living organisms of the Earth. They interact with the physical environment to regulate their distribution abundance, production, and evolution.

Question 2.
Name the abiotic factors of an environment.
Answer:
The abiotic factors of an environment include light, temperature, pressure, water, and salinity.

Question 3.
Define the niche of an organism.
Answer:
The niche of an organism is defined as the total position and function of an individual in its environment.

Question 4.
What is Van’t Hoff’s rule?
Answer:
Van’t Hoffs’s rule is that with the increase of every 10°C, the rate of metabolic activity doubles, or with the decrease of every 10°C, the metabolic rate is halved.

Question 5.
Define Phototaxis.
Answer:
Phototaxis is defined as the movement of an organism in response to light.
Eg: Moth (Positive Phototaxis), Earthworm (Negative Phototaxis).

Question 6.
Define porosity of soil.
Answer:
The porosity of the soil is defined as the percentage of soil volume occupied by pore space or by interstitial space.

Question 7.
Name any two plants present in hot deserts.
Answer:

1. Agave
2. Euphorbia

Question 8.
What is meant by cold deserts?
Answer:
Cold deserts are referred to as places where cold with snowfall and high overall rainfall throughout the winter and occasionally during summer.

Question 9.
Define population.
Answer:
The population is defined as any group of organisms of the same species, which can interbreed among themselves.

Question 10.
Explain population dispersion.
Answer:
Population dispersion is the tendency of the population to disperse or spread out in all directions until some barriers are reached.

Question 11.
What is meant by relative abundance?
Answer:
Relative abundance is a time-related index, which can show the changes in number in a population with respect to time. Eg: The number of birds of a particular species spotted in a unit area over a period of time.

Question 12.
Mention the factors, that regulate a population.
Answer:

1. Extrinsic factors. Density independent.
2. Intrinsic factors. Density-dependent.

Short answer questions

Question 1.
Distinguish between anadromous migration and catadromous migration.
Answer:

Anadromous Migration	Catadromous Migration
Anadromous migration is the migration of organisms from sea to freshwater. Eg: Salmon fish.	Catadromous migration is the migration of organisms from freshwater to sea. Eg: Eel.

Question 2.
What is structure adaptation? Give one example.
Answer:
Structural adaptation is the modification of the external and internal structures of an organism to suit them to adapt better to their environment.
Eg: Growing thicker fur in mammals to withstand the freezing climate in Arctic regions.

Question 3.
List out the adaptations of desert animals.
Answer:
The desert animals possess special adaptations to cope up with the desert environment. They are:

1. The animals living in the desert are capable of taping available water and storing sufficiently to withstand the heat.
2. Small nocturnal carnivores are predominant animals in the desert.
3. They are burrowers having cursorial, fossorial, and saltatorial adaptations.

Question 4.
Explain briefly about relative humidity.
Answer:
The amount of water vapor present in the air is known as relative humidity. It is expressed as a percentage of the amount needed for saturation at the same temperature. At a given temperature, a high percentage of humidity means that the air mixture is more humid. Humidity can be measured using an instrument called a Hygrometer.

Question 5.
Mention any three functions of soil.
Answer:
The functions of soil include:

1. The soil forms a medium for plant growth.
2. Soil is meant for water storage and purification.
3. Soil is the habitat for many organisms, which in turn modify and enrich the soil.

Question 6.
Explain the term “Photokinesis”.
Answer:
Photokinesis is a change in the speed of locomotion in the motile organisms or cells in response to a change in light intensity. This change of movement (or frequency of turning) is brought out by the change in the intensity of light. The movement may be undirected random movement of an organism in response to light.

Long answer questions

Question 1.
Give an account of adaptations of animals in response to temperature.
Answer:

1. Temperature is one of the major abiotic factors of the environment, which decide the survival of an animal in a particular environment.
2. The survival of an organism in an environment depends on its adaptation to temperature. Eurytherms are organisms, which can survive a wide range of temperatures.
   Eg: Cat, dog, tiger, and human.
3. Eurythmy is an aspect of thermoregulation in animals. Cold erythema is the adaptation of animals for the survival of the species during the ice ages. The ability of animals to survive in a wide range of temperatures increases a species ability to inhabit other areas – an advantage for natural selection.
4. Stenotherms are animals that can tolerate a narrow range of temperatures. Eg: Fish, frogs, lizards, and snakes.

The adaptation includes:

1. In the case of extreme temperatures, organisms have adapted by forming heat-resistant spores, cysts. Eg: Entamoeba
2. They form antifreeze protein to withstand severe cold.
   Eg: Arctic fishes.
3. They adapt to hibernation (Winter sleep) and aestivation (Summer sleep).
4. In certain conditions, migration is an appropriate adaptation to overcome extreme temperatures.

Question 2.
Draw and label the graphical representation of types of organisms based on temperature tolerance.
Answer:

Question 3.
List out any five adaptations of aquatic animals.
Answer:
The adaptations of aquatic animals include the following:

1. In fish, the pectoral fins and dorsal fins act as balancers and the caudal fin helps in changing direction as a rudder.
2. Streamlined body structure helps in the swift movement of animals in the water.
3. The presence of an air bladder filled with air helps for buoyancy.
4. Integument rich in mucous glands is protected by scales.
5. With well-developed excretory organs, they maintain water and ionic balance in their body.

Question 4.
Give an account of the role of migration in a population.
Answer:
Migration is the mass movement of a population from one place to another and back.
Migration is a peculiar and unique kind of mass movement to avoid extreme conditions of weather. The Siberian cranes migrate from Siberia to Vedanthangal in TamilNadu, in order to avoid severe winter cold in Siberia. Likewise, some fishes migrate from sea to freshwater (anadromous migration Eg: salmon) and some fresh water to sea (catadromous migration Eg: Eel).
Migration is of two types Emigration and Immigration.
Emigration: It is the type of migration outside the habitat, due to overcrowding of the population. This helps to prevent over-exploitation of habitat. It leads to the establishment of new habitat.
Immigration: It refers to the movement of population into the habitat from outside. It results in population levels. If the population increases beyond the carrying capacity of the habitat, it can result in increased mortality of immigrants or decrease the reproductive capability of individuals.

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)-(i); (s)-(ii)
(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:
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

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

5. Ethology is the scientific study of:
(a) animal reproduction
(b) plant reproduction
(c) animal behaviour
(d) plant response to light
Answer:
(c) animal behavior

6. Arrangement of body muscles in the form of bundles help in:
(a) metabolism
(b) locomotion
(c) hunting
(d) predation
Answer:
(b) locomotion

7. In the pond ecosystem, the column feeder is:
(a) catla
(b) mrigal
(c) common carp
(d) rohu
Answer:
(d) rohu

8. Tundra herbivores include:
(a) Arctic hare
(b) Snowy owl
(b) Arctic fox
(d) Bob cat
Answer:
(a) Arctic hare

9. Choose the odd one out:
(a) Light
(b) Temperature
(c) Water
(d) Soil microbes
Answer:
(d) Soil microbes

10. Identify the odd one:
(a) Polar bear
(b) Elephant
(c) Gaur
(d) Antelope
Answer:
(a) Polar bear

11. Find out the odd one:
(a) Trachea
(b) Gills
(c) Air bladder
(d) Lungs
Answer:
(c) Air bladder

12. Choose the odd one:
(a) Population density
(b) Ecological density
(c) Crude density
(d) Fecundity
Answer:
(d) Fecundity

13. Choose the correct pair.


Answer:
(b)

14. Find out the correct pair.

Answer:
(c)

15. Choose the incorrect pair.

Answer:
(d)

16. Which of the following is incorrect pair?

Answer:
(c)

17. Assertion: In a tropical forests, the soil nutrient-poor and acidic.
Reason: Decomposition is rapid and soils are subject to heavy leaching.
(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 wrong, Reason is correct.
(d) Assertion is correct, Reason is Wrong.
(e) Both Assertion and Reason are wrong.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

18. Assertion: Grassland biome often is characterized by high winds.
Reason: Dense tree cover is not present in the Grassland biome.
(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 wrong, Reason is correct.
(d) Assertion is correct, Reason is Wrong.
(e) Both Assertion and Reason are wrong.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

19. Assertion: Clay soil has a high water retention capacity due to high porosity.
Reason: The pore space between soil particle are more in clay 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 wrong, Reason is correct.
(d) Assertion is correct, Reason is Wrong.
(e) Both Assertion and Reason are wrong.
Answer:
(e) Both Assertion and Reason are wrong.

20. Assertion: in aquatic media, maintaining homeostasis and osmotic balance is a challenge.
Reason: Marine animals have appropriate adaptations to prevent cell shrinkage.
(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 wrong, Reason is correct.
(d) Assertion is correct, Reason is Wrong.
(e) Both Assertion and Reason are wrong.
Answer:
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

21. Choose the correct statement:
(a) Light does not influence reproduction.
(b) Light does not influence the growth of an organism.
(c) Light influences pigmentation.
(d) None of the above.
Answer:
(c) Light influences pigmentation.

22. Find out the incorrect statement:
(a) Water holding capacity of soil is directly dependent on soil porosity.
(b) Water holding capacity of soil is inversely dependent on soil porosity.
(c) Soil permeability is directly dependent on pore size.
(d) None of the above.
Answer:
(a) Water holding capacity of soil is directly dependent on soil porosity.

23. Choose the correct statement:
(a) Tundra biomes have long summers and short winters.
(b) Tundra biomes have long winters and short summers.
(c) Tundra biomes have little daylight in summer and long daylight in winter.
(d) None of the above.
Answer:
(b) Tundra biomes have long winters and short summers.

24. Which of the following statement is not correct?
(a) In aquatic animals, respiration is by gills.
(b) Presence of air bladders filled with air helps buoyancy.
(c) In fish, pectoral fins and dorsal fins act as balancers.
(d) None of the above statements is correct.
Answer:
(d) None of the above statements is correct.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 9 Applications of Biotechnology which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 9 Applications of Biotechnology

Very short answer questions

Question 1.
Define Biotechnology.
Answer:
Biotechnology is defined as a branch of Bioscience, through which various techniques of living things are used to make products or provide services for the benefits of human welfare.

Question 2.
Who did produce insulin from dogs? In which year?
Answer:
Best and Banting isolated insulin for the first time from the pancreatic islets of a dog in 1921.

Question 3.
What is somatic cell nuclear transfer?
Answer:
The somatic cell nuclear transfer is a technique for creating a viable embryo from a body cell and an egg cell.

Question 4.
Where is the gene for the synthesis of Blood-clotting factor VIII located?
Answer:
The genes for the synthesis of blood-clotting factor VIII are located in the X chromosome of a human being.

Question 5.
Distinguish between the traditional vaccine and recombinant vaccine.
Answer:

Traditional Vaccine	Recombinant Vaccine.
These vaccines may produce side effects in some patients.	The recombinant vaccine are of uniform quality and produce less side effects.
They are produced comparative less quantity.	They can be produced in large quantities.

Question 6.
What is meant by an edible vaccine? Explain briefly.
Answer:
Edible Vaccines are produced by introducing selected genes into plants and the transgenic plants are used to manufacture the encoded protein. They cause stimulation of both systemic and mucosal immune responses.

Question 7.
Explain DNA Vaccine.
Answer:
A DNA Vaccine consists of a gene encoding antigenic proteins, inserted into a plasmid, which is incorporated into the cells of a target animal. This would evoke an antibody response to the free-floating antigen secreted by the cells.

Question 8.
Mention any two trade names of recombinant hepatitis B Vaccine.
Answer:

1. Recombivax
2. Engerix – B

Question 9.
Expand SCID.
Answer:
SCID means Severe Combined Immune Deficiency.

Question 10.
Define Totypotency.
Answer:
Totypotency is a phenomenon of the ability of a single cell to divide and produces all of the differentiated cells in an organism.

Question 11.
Expand ELISA.
Answer:
ELISA means “Enzyme-Linked Immunosorbent Assay”

Question 12.
What is the enzyme used in PCR?
Answer:
The enzyme used in the PCR technique for synthesis DNA is Tag – DNA polymerase.

Short answer questions

Question 1.
Distinguish between traditional insulin and recombinant insulin.
Answer:

Traditional insulin	Recombinant insulin.
In evokes same allergic reactions in some diabetic patients due to minor differences in structure of the animal insulin as compared to human insulin.	Recombinant insulin is structurally uniform as that of human insulin and hence there may not be any allergic reaction in diabetic patients.
It can be produced comparative lesser quantity.	It can be produced in large quantities.

Question 2.
Explain how recombinant hGH is produced?
Answer:
A recombinant form of human growth hormone is called somatropin. This can be produced using recombinant DNA technology. The gene for hGH is isolated from the cell of the human pituitary gland and is inserted into a plasmid vector and then transferred to E.coli, which starts producing human growth hormone. The recombinant E.coli are mass cultured for mass production of this hormone using fermentation technology. This hormone is used as a drug to treat growth disorders in children.

Question 3.
Why did scientists choose yeast instead of E.coli for the production of interferon?
Answer:
Scientists preferred yeast, saccharomyces cerevisiae to E.coli for the production of interferon because E.coli does not possess the machinery for glycosylation of proteins, which is an essential part of recombinant interferon production.

Question 4.
Mention the three types of vaccine.
Answer:
The three types of vaccine are:

1. Subunit recombinant vaccine.
2. Attenuated recombinant vaccine and
3. DNA vaccine.

Question 5.
Write about stem cell banks.
Answer:
A stem cell bank is a place where the storage of stem cells, extracted and processed in laboratories. They may be used for the treatment of disease in the future when needed. Amniotic stem cells are derived from amniotic fluid and stored in an amniotic cell bank for future use. The cord blood stem cells are extracted from the umbilical cord during childbirth and stored in cord blood banks. The umbilical cord and umbilical blood are the main sources of stem cells, whereas, the placenta, amniotic sac, and amniotic fluid are also rich sources of quality stem cells.

Question 6.
What are natural protein adhesives? Mention their uses.
Answer:
Natural protein adhesives are produced by genetically engineered organisms and are non-toxic, biodegradable, and rarely trigger immune responses.
The uses of these protein adhesives include the reattachment of tendons and tissues, filling cavities in teeth, and broken bone repair.

Question 7.
List any three advantages of animal cloning.
Answer:

1. Animal cloning offers benefits for clinical trials and medical research.
2. It can help in the production of proteins and drugs in the field of medicine.
3. Animal cloning could help to restore endangered species.

Long answer questions

Question 1.
Draw the schematic representation of the production of human growth hormone.
Answer:

Question 2.
Draw the schematic diagram of the production of recombinant HB Vaccine.
Answer:

Question 3.
List the ethical issues encountered with the advent of Biotechnology.
Answer:
The following ethical issues encountered

1. Modern Biotechnology deals with genetic manipulation, which is against nature.
2. This genetic manipulation may lead to unknown consequences.
3. The major apprehension of recombinant DNA technology is that this technology may be misused deliberately for producing microorganisms for the purpose of war and this would cause epidemics and environmental catastrophes.
4. Many are concerned about the risk of genetic engineering.
5. Genetically modified organisms if introduced in the environment, the native organisms may be eliminated.

Question 4.
What are the steps involved in Polymerase Chain Reaction? Mention its uses.
Answer:
Polymerase Chain Reaction is carried out through denaturation, renaturation, or primer annealing and synthesis or primer extension.

1. The double-stranded DNA of interest is denatured to separate into two individual strands by high temperature. This is called denaturation.
2. Each strand is allowed to hybridize with a primer. This is known as renaturation or primer annealing.
3. The primer template is used to synthesis DNA by using Tag DNA polymerase. This is called primer extension.

Uses of PCR:

1. PCR is useful for the diagnosis of an inherited disorder or genetic diseases, viral diseases, bacterial diseases, etc.
2. PCR is used to study the differences in the genomes of two different organisms.
3. In the field of forensic medicine, PCR can be used.
4. Several virally induced cancers like cervical cancer caused by papillomavirus can be detected by PCR.
5. PCR is also used in the amplification of specific DNA segments, which is to be used in gene therapy.

Question 5.
Write down the steps involved in ELISA diagnosis.
Answer:

Choose the correct answers:

1. Match the following.

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

3. 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)

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. Which of the following transgenic animals?
(a) Rosie
(b) Dolly
(c) Wooly
(d) Somatic hybride
Answer:
(a) Rosie

6. Animal cloning involves
(a) transfer of gene
(b) the phenomenon of totipotency
(c) somatic cells
(d) tumor cells
Answer:
(b) the phenomenon of totipotency

7. In the PCR technique, which acts as the template?
(a) DNA molecule
(b) RNA
(c) mRNA
(d) cDNA
Answer:
(d) cDNA

8. In the ELISA test, the final activity of the enzyme yields a colored product indicating the presence of:
(a) Antibody
(b) Antigen
(c) Pathogen
(d) Infection
Answer:
(b) Antigen

9. Choose the odd man out.
(a) Kary Mullis
(b) Eva Engwell
(c) Darwin
(d) Peter Perlmanin
Answer:
(c) Darwin

10. Find out the odd one:
(a) ELISA
(b) PCR
(c) ADA
(d) Western plot
Answer:
(c) ADA

11. Chose the odd one:
(a) Denaturation
(b) Fragmentation
(c) Annealing
(d) Extension
Answer:
(b) Fragmentation

12. Identify the odd one:
(a) Human blood-clotting factor III
(b) Sex-linked disease
(c) Y chromosome-linked disease
(d) Haemophilia
Answer:
(c) Y chromosome-linked disease

13. Choose the odd man out:
(a) Best
(b) Peter Flemming
(c) Banting
(d) Rosie
Answer:
(d) Rosie

14. Which of the following is a correct pair?

Answer:
(b)

15. Choose the incorrect pair.

Answer:
(c)

16. Choose the correct pair.

Answer:
(a)

17. Assertion: Stem cells can differentiate into all types of cell that are derived from any of the three germ layers of ectoderm, endoderm and mesoderm.
Reason: Because stem cells are multipotent.
(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.

18. Assertion: The differences in the genomes of two organisms can be identified by PCR technique.
Reason: It can detect any quantity of DNA from any source.
(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:
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

19. Assertion: ADA deficiency is an autosomal recessive metabolic disorder.
Reason: In this patient, the T lymphocytes can elicit an immune response against invading pathogens.
(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:
(d) Assertion is correct, Reason is not correct.

20. Assertion: Interferons stimulate the cellular DNA to produce antiviral enzymes.
Reason: They inhibit viral replication and protect the cells.
(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:
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

21. Which of the following statement is correct?
(a) Recombinant hepatitis B vaccine is produced by cloning hepatitis B surface antigen.
(b) Hepatitis B vaccine is produced using E.Coli.
(c) Hepatic B vaccine is not an effective immune inducer.
(d) Nome of the above.
Answer:
(a) Recombinant hepatitis B vaccine is produced by cloning hepatitis B surface antigen.

22. Choose the incorrect statement.
(a) Stem cells are undifferentiated cells found in most of multicellular animals.
(b) They maintain their undifferentiated state even after undergoing numerous mitotic divisions.
(c) Human embryonic stem cells are unipotent.
(d) Human embryonic stem cells are pluripotent.
Answer:
(c) Human embryonic stem cells are unipotent.

23. Find out the correct statement.
(a) Transgenesis is a tool to study immune response.
(b) Transgenesis helps in the identification of viruses.
(c) Transgenesis is a powerful tool to study gene expression.
(d) None of the above.
Answer:
(c) Transgenesis is a powerful tool to study gene expression.

24. Choose the incorrect statement.
(a) Animal cloning aids stem cell research.
(b) Animal cloning process is tedious and very expensive.
(c) Animal cloning helps to save endangered species.
(d) All the statements are not correct.
Answer:
(d) All the statements are not correct.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 8 Microbes in Human Welfare which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 8 Microbes in Human Welfare

Very short answer questions

Question 1.
Name any two bacteria involved in bioremediation.
Answer:

1. Nitrosomonas europeae
2. Ideonella sakaiensis

Question 2.
Define mycorrhiza.
Answer:
Mycorrhiza is defined as a symbiotic association between a fungus and the roots of plants.

Question 3.
Mention any two insect biopesticides.
Answer:

1. The ladybird beetle.
2. Dragonfly

Question 4.
Explain the Yamuna Action plan.
Answer:
The government of India and Japan are involved in this project, which was formally launched in April 1993. The proposal of building a large number of sewage treatment plants along the banks of Yamuna River to treat raw sewage and to release only treated effluent into the river is agreed upon in this project.

Question 5.
What are methanogens?
Answer:
Methanogens are methane-producing bacteria. Eg: Methanol bacterium.

Question 6.
Define organic farming.
Answer:
Organic farming is a technique, in which the cultivation of plants and rearing of animals takes place in a natural way.

Question 7.
Define Bioremediation.
Answer:
Bioremediation is defined as a process in which naturally occurring or genetically modified microorganisms are used to reduce or degrade pollutants.

Question 8.
What is mycoherbicide?
Answer:
Mycoherbicide is a bioherbicide developed in 1981. It is derived from the fungus, Phytophthora palmivora. It controls the growth of strangler vine in citrus crops.

Question 9.
UV irradiation is an ideal disinfectant for wastewater why?
Answer:
UV irradiation is an ideal disinfectant for wastewater because ft does not alter the water quality except for inactivating microorganisms.

Question 10.
Name any two industrial processes in which microbes are involved.
Answer:

1. Fermented beverages
2. Antibiotic production.

Short answer questions

Question 1.
What is Biofuel? Explain.
Answer:
Biofuel is a fuel made from vegetable oils, fats, or greases. Biofuel can be used in diesel engines without altering the engine. The qualities of biodiesel include nontoxic, biodegradable, and production of low level of air pollutants than petroleum-based diesel fuel. The plants identified for biofuel production are Jatropha curcas and Pongamia sp.

Question 2.
Mention any three genetically engineered microorganisms and their functions.
Answer:

1. Genetically modified E.coli – Human insulin.
2. Pseudomonas putida – Bioremediation.
3. Genetically engineered streptococcus – To remove clots from the blood vessels.

Question 3.
List any three differences between chemical farming and organic farming.
Answer:

Chemical farming	Organic fanning
In chemical farming chemical fertilizers and pesticides are used.	In organic farming natural organic manure and bio pesticides are used.
The fertility of soil is reduced.	Protecting the soil quality using organic materials.
Pesticide residues will be present in the produce.	Since bio pesticides are used, no pesticides residue in the produce.

Question 4.
Mention any three examples of biofertilizers.
Answer:
The main sources of biofertilizers are bacteria, fungi, and cyanobacteria.

1. Rhizobium is symbiotic nitrogen-fixing bacteria. It can fix atmospheric nitrogen into organic forms. They are present in the root nodules of leguminous plants.
2. Mycorrhiza is a symbiotic association between a fungus and the roots of the plants. The fungus absorbs the phosphorous from the soil and transfers to the plant.
3. Oscillatoria is a cyanobacterium-free living, prokaryotic organism. It can fix atmospheric nitrogen into useful forms and is used as a biofertilizer.

Question 5.
How is a wine produced?
Answer:
Wine is made through a process of fermentation of grape juice. Saccharomyces cerevisiae is responsible for the fermentation of grape juice into alcohol. Red wine and white wine are the two types of wines available. The black grapes along with skin ‘ and even stem are used for making red wine. The juice of either white or black grapes without their skin and stem is used for the preparation of white wine.

Long answer questions

Question 1.
Explain the role of microbes in biogas production.
Answer:
Biogas is a mixture of different gases like methane (63%) with CO₂ and hydrogen. The agricultural wastes, manure, municipal wastes, plant materials, sewage sludge, food waste, etc., form the raw materials for the production of biogas. In biogas production, the organics is converted into gas and organic fertilizer by microbes under anaerobic conditions.
Methanogens are methane-producing bacteria, responsible for biogas production. Methanobacterium is the common bacteria used for the production of biogas, which bums with a blue flame. The bacteria are present in the anaerobic sludge and rumen of the cattle.
The excreta of cattle is called ‘Gobar’, which forms the inoculum of the anaerobic process in the biogas unit. The biogas/ gobar gas is also generated by the anaerobic decomposition of cattle dung, by the methanogenic bacteria.

Question 2.
Draw the schematic diagram of the action of the toxin.
Answer:

Question 3.
How is industrial alcohol produced?
Answer:
Industrial alcohol is the ethanol (C₂H₅OH), produced in a large scale, using the yeast, Saccharomyces cerevisiae. It is used for industrial, laboratory and fuel purposes Bacteria such as Zymomonas mobilis and Sarcina ventricuta are also used in the industrial production of alcohol.
Molasses, com, potatoes, and wood waste are the raw materials for the commercial production of industrial alcohol. During this process, the milling of feedstock, followed by the addition of dilute or fungal amylase from Aspergillus makes the drawing material break down the starch into fermentable sugar. Yeast is then added to convert the sugars into ethanol. The concentration of alcohol in the brewing is 96%, which is distilled to obtain ethanol. Ethanol is used as biofuel an alternative or additive of gasoline.

Question 4.
Draw and label the schematic diagram of the sewage treatment process.
Answer:

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

2. Match the following:

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

3. Match the following:

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

4. The queen of drugs is:
(a) Streptomycin
(b) Chloromycin
(c) Kanamycin
(d) Penicillin
Answer:
(d) Penicillin

5. Which one is not an antibiotic?
(a) Erythromycin
(b) Cyclosporin A
(c) Bacitracin
(d) Neomycin
Answer:
(b) Cyclosporin A

6. The study of wine and winemaking is known as
(a) Zymology
(b) Homology
(c) Oenology
(d) Ornithology.
Answer:
(c) Oenology

7. Choose the odd man out:
(a) Zymomonas mobilis
(b) Sarcina ventriculi
(c) Saccharomyces cerevisiae
(d) Clostridium butyricum
Answer:
(d) Clostridium butyricum

8. Identify the odd one out:
(a) Yogurt
(b) Paneer
(c) Bread
(d) Cheese
Answer:
(c) Bread

9. Find the odd one out:
(a) Ladybird beetle
(b) Dragonfly
(c) Trichoderma
(d) E.coli
Answer:
(d) E.coli

10. Which of the following is the correct pair?

Answer:
(b)

11. Which of the following is the incorrect pair?

Answer:
(c)

12. Which of the following is the incorrect pair?

Answer:
(a)

13. Assertion: Microbian fuel cells work by allowing bacteria to oxidize or reduce organic molecules.
Reason: Bacterial respiration is basically on big redox reaction in which electrons are being moved around.
(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 wrong.
(d) Both Assertion and Reason are wrong.
Answer:
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

14. Assertion: Biogas is produced by the breakdown of organic matter under anaerobic conditions.
Reason: The breakdown of raw organic waste is carried out by anaerobic bacteria.
(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 wrong.
(d) Both Assertion and Reason are wrong.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

15. Assertion: The Biological Oxygen Demand (BOD) is high in raw sewage.
Reason: The greater the BOD in wastewater, the lesser is its polluting potential.
(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 wrong.
(d) Both Assertion and Reason are wrong.
Answer:
(c) Assertion is correct, Reason is wrong.

16. Which of the following is a correct statement?
(a) The sewage contains a large amount of organic matter and fewer of microbes.
(b) The sewage contains a large amount of organic matter and microbes.
(c) The sewage contains less amount of organic matter and a large amount of microbes.
(d) None of the above.
Answer:
(b) The sewage contains a large amount of organic matter and microbes.

17. Choose the incorrect statement:
(a) Cheese is a dairy product produced by coagulation of milk protein, casein
(b) The enzyme rennet is used for the coagulation of milk protein.
(c) Most cheeses is made with a starter bacteria Lactococcus.
(d) All the above statements are not correct.
Answer:
(d) All the above statements are not correct.

18. Indicate the correct statement:
(a) Aerobic microbes degrade the pollutants in the absence of oxygen.
(b) Pseudomonas putida is a genetically modified microorganism.
(c) It is multiplasmid organic matter degrading bacterium.
(d) It can digest the nitrogenous materials in the soil.
Answer:
(b) Pseudomonas putida is a genetically modified microorganism.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 7 Human Health and Diseases which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 7 Human Health and Diseases

Very short answer questions

Question 1.
Name any two viral diseases.
Answer:

1. Chickenpox
2. Dengue fever.

Question 2.
Name the causative agents of diseases: cholera and measles.
Answer:

1. Cholera – Vibrio cholerae,
2. Measles-Rubella virus.

Question 3.
Mention any two fungal diseases.
Answer:

1. Ringworm disease
2. Dermatomycosis

Question 4.
Give the scientific names of roundworm and filarial worm.
Answer:

1. Round worm – Ascaris lumbricoides.
2. Filarial worm – Wuchereria bancrofti

Question 5.
Define immune response.
Answer:
The immune response is defined as the mechanisms used by the body for protection from environmental agents that are foreign to the body.

Question 6.
What is innate immunity?
Answer:
Innate immunity is the natural phenomenon of resistance to infection which an individual possesses right from birth.

Question 7.
Define cell-mediated immunity.
Answer:
Cell-mediated immunity is defined as an immunological phenomenon through which the pathogens are destroyed by cells without producing antibodies.

Question 8.
Define humoral immunity.
Answer:
Humoral immunity is defined as a process through which the pathogens are destroyed by the production of antibodies.

Question 9.
What is the spleen?
Answer:
The spleen is a secondary lymphoid organ, located in the upper part of the abdominal cavity close to the diaphragm. It brings humoral and cell-mediated immunity and contains B and T cells.

Question 10.
What are the functions of immunoglobulins?
Answer:
The functions of immunoglobulin include agglutination, precipitation, opsonization, and neutralization.

Question 11.
Define vaccine therapy.
Answer:
Vaccine therapy is defined as a method of treatment of disease by the use of vaccines.

Question 12.
Who developed the polio vaccine and rabies vaccine?
Answer:

1. The Polio vaccine is first developed by Dr. Jonas Salk.
2. The rabies vaccine is developed by Louis Pasteur.

Question 13.
What is the latest contribution of vaccines?
Answer:
The latest contribution in vaccines is the DNA vaccine or recombinant vaccine.

Question 14.
Define Anaphylaxis.
Answer:
Anaphylaxis is defined as a classical, sudden, systematic, severe hypersensitivity reaction occurring as a result of rapid generalized mast-cell degranulation.

Question 15.
Define Autoimmunity.
Answer:
Autoimmunity is defined as an abnormal immune response, in which the body produces antibodies cytotoxic T cells in response to self-antigens and destroys the individual’s own tissue.

Short answer questions

Question 1.
What are types of autoimmune diseases? Explain.
Answer:
Autoimmune diseases in humans are divided into two categories namely organ-specific and non-organ specific auto-immune diseases. The organ-specific immune disease is mostly directed against one organ. The functions performed by the organ are blocked by the antibodies produced.
Eg: Hashimoto’s thyroiditis, Grave’s disease, and Addison’s disease (adrenal gland).
The non-organ specific disorders are otherwise known as systemic disorders in which autoimmune activity is widely spread throughout the body.
Eg: Rheumatoid arthritis and multiple sclerosis.

Question 2.
Explain Immunotherapy.
Answer:
Immunotherapy is otherwise called biological therapy, in which the substances made by the body or in a laboratory (monoclonal antibodies) are used to improve or to resist the immune system’s function. The immunotherapy of cancer involves different approaches. After the removal of the gross tumor, the patient is given immunotherapy to get nd of residual malignant cells. An integrated approach of treatment by combining surgery, radiotherapy, chemotherapy, and immunotherapy is the best treatment for cancer.

Question 3.
List the symptoms of mental depression.
Answer:

1. Loss of self-confidence and self-esteem,
2. Showing anxiety.
3. Not being able to enjoy things that are usually pleasurable or interesting.

Question 4.
List the causative agents, mode of transmission, and symptoms of the diseases – Cholera, Pneumonia, and Tuberculosis.
Answer:

Question 5.
Differentiate between normal cells and cancer cells.
Answer:

Normal cell	Cancer Cell
Normal cells are small having uniformly shaped nuclei and relatively large cytoplasmic volume.	Cancer cells are large having variable shaped nuclei and relatively small cytoplasmic volume.
Cell size and shape are confirmed and form discrete tissues.	They are variable in cell size and shape. Disorganized arrangement of cells.
They may possess differentiated cell structures. Normal presentation of cell surface markers.	Loss of normal specialized features Elevated expression of certain cell markers.
Lower levels of dividing cells, clearly demarkated cell tissues.	Large number of dividing cells and poorly defined tumor boundaries.

Question 6.
Write briefly about swine flu.
Answer:
Swine flu is caused by the HINI virus strain. This flu was first recognized in the year 1919. Fever, cough, sore throat, chills, weakness, and body ache are the common symptoms of this flu. Children, pregnant women, and elderly people are highly susceptible to infection.

Question 7.
Draw and label the structure of Trypanosoma gambiense.
Answer:

Question 8.
Explain adenoids and their function.
Answer:
Adenoids are glands located at the roof of the mouth, the place where the nose connects to the throat. The main function of adenoids is the production of antibodies, which help to resist infections. The adenoids shrink during adolescence and may disappear during adulthood.

Long answer questions

Question 1.
Draw the structure of HIV and label the parts.
Answer:

Question 2.
Give an account of fungal diseases in humans.
Answer:
Fungal diseases are known before bacterial diseases in humans. The fungal genera, Trichophyton, Microsporum, and Epidermophyton cause a skin infection in human being called Dermatomycosis.
Ring Worm is also one of the most common diseases in humans. The main symptoms of this disease include the appearance of dry, scaly lesions on the skin, nails, and scalp. Generally, these fungi grow in skin folds such as those in-between toes and in the groin due to heat and moisture. Tenea pedis causes ringworms of feet called Athlete’s feet. The infection of ringworms is acquired from the soil. The transmission of this disease may also be carried by using clothes, towels, and comb used by infected persons.

Question 3.
Distinguish between primary immune response and secondary immune response.
Answer:

Primary immune response	Secondary immune response.
Primary immune response occurs as a result of primary contact with as antigen.	Secondary immune response happens as a result of second or subsequent contact with the same antigen.
During 7 to 10 days of infection, antibody level reaches the peak.	Within 3 to 5 days the antibody level reaches the peak.
Long period is to establish immunity.	Short time is required to establish immunity.
In this, there is rapid decline in antibody level.	Antibody level remain high for longer period.
Primary immune response mainly in lymph nodes and spleen.	Secondary immune response generally appears is bone marrow, followed by spleen and lymph nodes.

Question 4.
List the different groups of drugs along with their effects.
Answer:

Question 5.
Mention any five viral diseases and what is the mode of their transmission and symptoms?
Answer:

Activities

Activity 1: Students examine the impact of microorganisms in our daily life and consider their applied potential. They can also conduct independent research and communicate their findings.

1. Examine the microorganisms in curd – Lactobacillus sp.
2. Examine the microorganisms in baking – yeast.
3. Examine the microorganism present in the root nodules of the pea plant – Rhizobium.

Students can do experiments with curd fermentation. The boiled and cooled milk can be inoculated with little curd as an experiment and another part without inoculum serves as a control. Observe both with and without inoculum after 12 hrs, Examine the organisms in both, and report the findings.

Activity 2: Students prepare wet mounts to observe the microbes found in curd.
Observation: Lactobacillus sp.

Activity 3: The leader will blow bubbles at the group of students to demonstrate how some diseases can be airborne?
Observation: Bubbles spread in all directions in the air, simulating the airborne pathogen.

Activity 4: Which parasite acts as a transporter host for other parasites? Discuss.
Trypanosoma brucei is a protozoan known to cause sleeping sickness in humans but actually uses tests fly as its definite host, as that is where it develops into maturity and reproduces. The definite host for a Plasmodium, the genus of parasite that causes malaria, is the female Anopheles mosquito.

Activity 5: Your friends call you a ‘sissy boy’ because you do not smoke or chew tobacco. What answer will you give? How will you prove your strength?

1. Smoking and tobacco chewing lead to lung cancer and check cancer respectively due to the presence of carcinogenic nicotine.
2. Lung diseases caused by smoking include COPD, including emphysema and chronic bronchitis smokers are 12 to 13 times more likely to die from COPD than non-smokers. Tobacco chewers are more vulnerable to the onset of cancer.

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

3. 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)

4. Match the following (in relation to drugs):

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

6. The ring worm disease is caused by:
(a) A worm
(b) Bacteria
(c) Fungi
(d) Virus
Answer:
(c) Fungi

7. The duration of the Erythrocytic cycle in quartan malaria is:
(a) 48 hours
(b) 72 hours
(c) 36 hours
(d) 40 hours
Answer:
(b) 72 hours

8. The cholera is a bacterial disease and the site of infection is:
(a) Liver
(b) Lungs
(c) Skin
(d) Intestine
Answer:
(d) Intestine

9. Which of the following is the primary lymphoid organ?
(a) Thymus
(b) Lymph node
(c) Spleen
(d) Pancreas
Answer:
(a) Thymus

10. Regular use of morphine effects:
(a) Intestine
(b) Central Nervous system
(c) Cardiovascular system
(d) Liver
Answer:
(b) Central Nervous system

11. Choose the odd man out:
(a) Cocaine
(b) Nicotine
(c) Cannabis
(d) Amphetamine
Answer:
(c) Cannabis

12. Find the odd one out:
(a) Precipitin
(b) Agglutinin
(c) Opsonin
(d) Creatin
Answer:
(d) Creatin

13. Indicate the odd one out:
(a) Lymphocytes
(b) Monocytes
(c) Red Blood cells
(d) Neutrophils
Answer:
(c) Red Blood cells

14. Choose the odd one out:
(a) Bursa of fabricius
(b) Spleen
(c) Peyer’s patebes
(d) Lumph node
Answer:
(a) Bursa of fabricius

15. Identify the odd one out:
(a) Cholera
(b) Elephantiasis
(c) Diphtheria
(d) Malaria
Answer:
(b) Elephantiasis

16. Choose the correct pair:

Answer:
(c)

17. Which of the following is an incorrect pair?

Answer:
(d)

18. Choose the correct pair:

Answer:
(a)

19. Find out the incorrect pair:

Answer:
(d)

20. Which of the following is a correct pair?

Answer:
(b)

21. Assertion: Alcohol is a psychoactive drug, affecting a person’s mind and behavior.
Reason: Alcohol acts on the brain and slows down the activity of the brain.
(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 wrong.
(d) Both Assertion and Reason are wrong.
Answer:
(a) Assertion and Reason are correct, Reason is the correct explanation of Assertion.

22. Assertion: When a cell undergoes malignant transformation, it acquires a new surface antigen and may also lose some normal antigens.
Reason: These antigens are present on the membranes of malignant cells.
(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 wrong.
(d) Both Assertion and Reason are wrong.
Answer:
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

23. Assertion: The third-generation vaccine contains the purest and the highest potential vaccine.
Reason: Because they are natural potential vaccines.
(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 wrong.
(d) Both Assertion and Reason are wrong.
Answer:
(c) Assertion is correct, Reason is wrong.

24. Assertion: B lymphocytes leave the bone marrow and mature in the thymus gland.
Reason: Once mature, they accumulate in the same areas of T cells.
(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 wrong.
(d) Both Assertion and Reason are wrong.
Answer:
(d) Both Assertion and Reason are wrong.

25. Assertion: Active immunity is acquired through the use of a person’s immune responses, which lead to the development of memory cells.
Reason: Active immunity results from an infection or an immunization.
(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 wrong.
(d) Both Assertion and Reason are wrong.
Answer:
(b) Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

26. Which of the following statement is correct?
(a) The unique feature of acquired immunity is antigenic specificity.
(b) The unique feature of acquired immunity is diversity.
(c) The unique feature of acquired immunity is recognition of self and non-self and immunological memory.
(d) All the above
Answer:
(d) All the above

27. Choose the incorrect statement:
(a) Innate immunity is the natural phenomenon of resistance to infection.
(b) These defense mechanisms are non-specific.
(c) This type of immunity results from an infection.
(d) It is otherwise known as natural immunity.
Answer:
(c) This type of immunity results from an infection.

28. Indicate the correct statement.
(a) Filariasis is a viral disease
(b) Filariasis is a bacterial disease
(c) Filariasis is a fungal disease
(d) None of the above
Answer:
(d) None of the above

29. Choose the incorrect statement:
(a) Neurotropic disease includes rabies and polio.
(b) Yellow fever and dengue fever are grouped under viscerotropic diseases.
(c) Dermotropic diseases include chickenpox and measles.
(d) None of the above statements is correct.
Answer:
(d) None of the above statements is correct.

30. Find out the correct statement:
(a) In the primary immune response, antibody level reaches a peak in 8-12 days.
(b) Primary immune response occurs as a result of primary contact with an antigen.
(c) In this, there is a rapid increase in antibody level.
(d) None of the above.
Answer:
(b) Primary immune response occurs as a result of primary contact with an antigen.

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:

Homologous structure	Analogous structures
Structures, which are similar in origin, but perform different functions.	Analogous structures are the organs having different structures but performing similar function.
Eg: Fore arms and hind limbs of vertebrates.	Eg: Insect wing and bird wing

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:

Homo habilis	Homo erectus
Homo habilis lived about 2 mya	Homo erectus lived around 1.7 mya.
Their brain capacity was between 650-800 cc.	They are the first human like being. They had brain capacity of 900 cc.
They are probably vegetarian.	They are probably meat eaters.
They have bipedal locomotion. They used chipped stones as tools.	They are much closer to human, but skull was flatter, and thicker than modem man.

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:

One gene – one enzyme hypothesis	One gene -one polypeptide hypothesis
One gene – one enzyme hypothesis states that one gene control the production of one enzyme. This hypothesis is postulated by George Breadle and Edward Tatum.	One gene – one polypeptide hypothesis states that a gene can code for only one polypeptide and more than one polypeptide chain may compose an enzyme. Thus one gene controls the production of only one polypeptide chain of an enzyme.

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:

Nucleoside	Nucleotide
Nucleoside is formed by a chemical linkage of nitrogenous base with one molecule of sugar at one carbon atom.	Nucleotide is formed by attaching a phosphate group to the 5′ carbon of same sugar. Nucleotides are polymerized to form polynucleotides.

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:

Monocistronic mRNA	Polycistronic mRNA
Each mRNA carrys only a single gene.	Cluster of related genes form operon.
Each mRNA encodes information for the synthesis of only a single protein.	They transcribed together to give a single mRNA.
It is present in eukaryotes.	They are present in prokaryotes.

Question 6.
Distinguish between promoters and operators.
Answer:

Promoters	Operators
Promoters are the single sequences of DNA that initiate RNA synthesis.	Operators are present between promoters and structural genes.
Prior to the initiation of transcription, RNA polymerase binds to the promoter.	The repressor protein binds to the operator region of the operon.

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:

Down’s Syndrome	Turner’s Syndrome
Down’s syndrome is due to Trisomic-21 condition.	Turner’s syndromes due to loss of a X chromosome.
The symptoms include severe mental retardation and defective development of CNS.	Persons with this syndrome have 44AA+XO chromosomes.
Other symptoms include increased separation between eyes, flattened nose, malformed ears.	The females are sterile.
Mouth is always open and the tongue protrudes.	The symptoms include low stature, webbed neck, under developed breast, rudimentary gonads ack of menstrual cycle during puberty.

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.