Reproductive Health — BIOLOGY STD 12 Science — Question

Explain the process of DNA replication.

With the help of suitable diagram, describe the conducting system of human heart.

Samya visited a zoo with her mother, on watching the cheetah, she wondered how he uses his forelimbs for running. While the same forelimbs in bats are used for flying. She wanted to know more about it and so asked her mother (a biology teacher) about it. Her mother explained her how forelimbs are modified in different animal groups for different functions.

1. What are such organs called?
2. Give an example of such organs from the plant world.
3. What led to the origin of such organs?
4. What are the values shown by Samya?

Pavlov’s experiment about conditional reflex.

State the modifications of forelimb in animals as an example of homology.

Answer the following questions:
Explain the events that occur in a graafian follicle at the time of ovulation and thereafter.

Define geitonogamy and xenogamy. Give advantages of self pollination and cross pollination. Explain how dichogamy favours cross pollination.

Give an account of alcoholic beverages.

In a person, Pars distalis part of the Pituitary gland is not producing hormones in sufficient quantity. Explain the effects it will produce with respect to the different hormones.###Give names and functions of hormones secreted by adenohypophysis.

Answer the following questions:
Draw a diagrammatic sectional view of a human seminiferous tubule, and label Sertoli cells, primary spermatocyte, spermatogonium and spermatozoa in it.