Human Reproduction — BIOLOGY STD 12 Science — Question

The following is the flow chart highlighting the steps in DNA fingerprinting technique. Identify a, b, c, d, e and f.

How many primary follicles are left in each ovary at puberty?

Write a short note on Double fertilisation.

Answer the following questions:
What are mycorrhiza? How does it act as a biofertiliser?

1. Write the importance of measuring the size of a population in a habitat or an ecosystem.
2. Explain with the help of an example how the percentage cover is a more meaningful measure of population size than more numbers.

1. Draw a labelled schematic diagram of a replication fork showing continuous and discontinuous replication of DNA strands.
2. State a reason why is the replication continuous and discontinuous in the diagram drawn.

How does a mutagen induce mutation? Explain with example.

How can Hardy-Weinberg equilibrium be affected? Explain giving three reasons.

Answer the following questions:
Why are grasshopper and Drosophila said to show male heterogamety? Explain.

Insulin in the human body is secreted by pancreas as prohormone/ proinsulin. The schematic polypetide structure of proinsulin is given below. This proinsulin needs to undergo processing before it becomes functional in the body. Answer the questions that follow:

1. State the change the proinsulin undegoes at the time of its processing to become functional.
2. Name the technique the American company Eli Lilly used for the commercial production of human insulin.
3. How are the two polypeptides of a functional insulin chemically held together?