CBSE Class 12 Biology Revision Worksheet

1 Which individuals can be termed as clones? 

2 How do the following organisms reproduce: a) Paramoecium b) Penicillium? 

3 Which part of banana and ginger plants are used for vegetative propagation? 

4 In Bryophyllum, leaf margins show green structures. What are these? Name another plant having such structure.

5 What is the vital link between two generations? 

6 Give term for the condition in which a single organism possesses both sex organs. 

7 Why do hilly areas of Kerala, Karnataka and Tamil Nadu transform into blue Stretches that attracts many tourists?

8 Define ‘oestrus’ and ‘menstrual’ cycles. 

9 Differentiate between homogamete and heterogametes. 

10 What regulates the reproduction processes and the associated behavioral expressions in organisms?

11 Give any three differences between asexual and sexual reproduction. 

12 Enlist the changes that occur post- fertilization in plants.

1. Name the asexual reproductive structure in

1 How does vegetative propagation take place in plant like Bryophyllum? 

2 Name the two parts of a typical anther.

3 Name the primary sex organs in human male and female.

4 Why a ban has been imposed on amniocentesis?

5 Write the functions of Leydig cells and Sertoli Cells.

6 Differentiate between GIFT and ZIFT. 

7 a) Name the layers of the uterus from outside to inside.

b) Write the name of the location where fertilization takes place in humans.

8 A typical pollen grain has two layers. Name them and mention its chemical composition. 

9 Name the common asexual reproductive structure in

a) Sponge

b) Penicillium

c) Hydra

d) Chlamydomonas

10 Explain the natural methods of preventing pregnancy.

1. What is a test cross? Depict the same to show its significance.

2. Differentiate between codominance and incomplete dominance. Give an account of multiple allelism with example.

3. Why is DNA considered to be a better genetic material than RNA inspite of the fact that RNA had evolved earlier to DNA?

4. Enlist the differences between Turner’s syndrome and Klinefelter’s syndrome.

5. Who performed ‘Blender’ experiment? What was the objective of this experiment? Explain the process in detail.

6. Why is DNA replication called as semiconservative and semidiscontinuous? Explain.

7. Illustrate schematically the process of transcription of a gene in a bacterium.

8. Describe post transcriptional modifications occurring in a hnRNA. Explain the process of translation in a eukaryote.

9. Illustrate the life cycle of a retrovirus.

10. What is operon? Expand your idea about operon concept with respect to inducible operon and repressible operon.

11. What is DNA fingerprinting? List the uses of DNA fingerprinting technique.

12. Give an account of human genome project.

13. What is adaptive radiation? Give two examples to explain it. Give examples from plants showing homology.

14. ”A population has been exhibiting genetic equilibrium.” Answer the following with regard to the above statement

a. Explain the above statement

b. Name the underlying principle.

c. List any two factors which would upset the genetic equilibrium of the population.

d. Take up any one such factor and explain how the gene pool will change due to that factor.

15. Explain the role of microbes as biocontrol agent and their product as bioactive molecules, with exampl

Q A Fill in the blanks using suitable words:

1 Replication of DNA takes place in __ to ____ direction.

2 AUG Codon codes for ______________.

3 ____ _____ and _______ are examples of nonsense codon..

4 Scientific name of a Fruitfly is __________________

5 Females having sex chromosome as XO is said to be suffering from _________ ________.

Q B Answer the following questions in brief:

1 Who is the father of Genetics?

2 What is the scientific name of the plant used to give out “Laws of inheritance”?

3 What is the phenotypic ratio of a dihybrid cross in F2 generation?

4 Name the pattern of inheritance where the genotypic and phenotypic ratio of a cross comes out to be same in F2 generation.

5 Name the disorder observed in a female, when one of her sex chromosome is missing.

6 What is the phenotypic ratio of a test cross?

7 Who gave an experimental proof of the fact that the DNA replication is semi conservative?

8 What is the number of chromosomes in a man suffering from Knilefelter’s syndrome?

Q C Define the following term

1 Parturition

2 Genetic codon

3 Homologous organs

Q D Answer the following questions in detail with the help of diagram.

1 Explain Hardy –Weinberg principle with the help of diagram showing operation of natural selection.

2 Explain the steps of protein synthesis

1. When did flowering occurs last time in Strobilanthus Kunthiana? 1

2. Name the part of flower that contributes to fruit formation in strawberry and Guava respectively 1

3. How is polyspermy prevented in humans? 1

4. Offsprings formed due to sexual reproduction have better chances of survival. Why? 1

5. Name developmental stage in humans which gets implanted in uterine wall. 1

6. Name the type of evolution that has brought the similarity as seen in potato tuber and sweet potato. 1

7. What do you understand by ‘degeneracy’ of the genetic code? 1

8. Name the molecule synthesized by ‘i’ gene in lac operon. How does this molecule get inactivated? 1

9. Give reasons

i. Pollen grains are well preserved fossils.

ii. Cells of tapetum have dense cytoplasm. 1

1. Distinguish active and passive immunity.

2. Explain the structure of antibody molecule with a neat diagram.

3. On what principle is immunization done?

4. How is primary immune response different from secondary immune response?

5. What is innate immunity? Explain the different types.

6. Name the causative organism for Ringworm, cold , pneumonia, ascariasis.

7. What are the symptoms of amoebiasis, typhoid and elephantiasis.

8. With a neat diagram explain the lifecycle of AIDS virus.

9. Give a schematic sketch of malarial parasite’s life cycle.

10. How is sewage treatment done? What are the various steps involved?

11. List the function of statins, cyclosporin A ,lactic acid ,protease, lipase.

12. What is inbreeding depression? How is it overcome?

13. Expand MOET. List the steps involved. What is its significance?

14. What is somatic hybridization? How is it done?

15. Define meristem culture.

16. What is tissue culture? List the substances required for growing plants in invitro condition.

17. What is biofortication. Give few examples.

18. Why is mutation breeding done? Give an example.

19. List the steps to be followed during bee keeping.

20. Expand KVIC, IARI.