Evolution — BIOLOGY STD 12 Science — Question

How is PCR technique beneficial in biotechnology? How are the developed countries related to biopiracy cases? Explain with an example.

A schematic representation of Polymerase Chain Reaction (PCR) up to the extension stage is given below. Give answers of the following questions.

1. Name the process A.
2. Identify B.
3. Identify C and mention its importance in PCR.

Discuss the role of women and communities in protection and conservation of forests.

Explain - Nucleoside & Nucleotide

Explain human female reproductive system.

What is the ozone shield and why is it important? Name the gases that cause stratospheric ozone depletion.

1. In pBR322, foreign DNA has to be introduced in tetR region. From the restriction enzymes given below, which one should be used and why?

PvuI, EcoRI, BamHI

2. Give reasons, why the other two enzymes cannot be used.

List the changes that the primary ooctye undergoes in the tertiary follicular stage in the human ovary.

1. Name the organic material exine of the pollen grain is made up of. How is this material advantageous to pollen grain?
2. Still it is observed that it does not form a continuous layer around the pollen grain. Give reason.
3. How are 'pollen banks' useful?

Public all over India is very much concerned about the deteriorating air quality in large parts of North India. Alarmed by this situation the Resident's Welfare Association of your locality organised an awareness programme entitled "Bury not burn'. They invited you, being a biology student to participate.

1. How would you justify your arguments that promote burying and discourage burning? (Give two reasons).
2. With the help of flowcharts, one for each practice, depict the chain of events that follow.