Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

What are the various routes by which transmission of human immunodeficiency virus takes place?

What are viruses parasitising bacteria called? Draw a well labelled diagram of the same.

As a senior biology student you have been asked to demonstrate to the students of secondary level in your school, the procedure(s) that shall ensure cross-pollination in a hermaphrodite flower. List the different steps that you would suggest and provide reasons for each one of them.

What are transgenic plants? Give some example.

Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?

Write a short note on female accessory ducts.

Explain three basic steps to be followed during genetic modification of an organism.

A large number of married couples the world over are childless. It is shocking to know that in India the female partner is often blamed for the couple being childless.

1. Why in your opinion the female partner is often blamed for such situations in India? Mention any two values that you as a biology student can promote to check this social evil.
2. State any two reasons responsible for the cause of infertility.
3. Suggest a technique that can help the couple to have a child where the problem is with the male partner.

By which technique are the gene defects identified in a child or fetus treated? Explain with example.