CBSE Class 12 Biology Question Paper Solved 2019 Set B

CBSE Class 12 Biology Question Paper Solved 2019 Set B. Students can download the last year board exams question papers using the link below. Free download of examination question papers with solutions. Last 10 year question papers should be practised to get better marks in examinations.

SECTION – A

1. British geneticist R.C. Punnett developed a graphical representation of a genetic cross called “Punnett Square”. Mention the possible result this representation predicts of the genetic cross carried.

2. State the two principal outcomes of the experiments conducted by Louis Pasteur on origin of life.

3. Name the layer of the atmosphere that is associated with ‘good ozone’.

OR

Mention the term used to describe a population interaction between an orchid growing on a forest tree.

4. What are ‘flocs’, formed during secondary treatment of sewage ?

OR

Write any two places where methanogens can be found.

5. At what stage does the meiosis occur in an organism exhibiting haploidic life cycle and mention the fate of the products thus produced.

SECTION – B

6. You are conducting artificial hybridization on papaya and potato. Which one of them would require the step of emasculation and why ? However for both you will use the process of bagging. Justify giving one reason.

7. How would the gene flow or genetic drift affect the population in which either of them happen to take place ?

8. Differentiate between the roles of B-lymphocytes and T-lymphocytes in generating immune responses.

OR

Principle of vaccination is based on the property of “memory” of the immune system. Taking one suitable example, justify the statement.

9. Explain the relevance of “Totipotency” and “Somaclones” in raising healthy banana plants from virus infected banana plants. 

10. How is a continuous culture system maintained in bioreactors and why ? 

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