Ecosystems — BIOLOGY STD 12 Science — Question

Some parents wrote a complaint letter to the local municipality to remove all the hoardings in the city, advertising the use of condoms and matters relating to AIDS prevention. The children of these parents came to know about the matter and raised their voice against removal of the hoardings. The parents were convinced by the awareness level of their children and withdrew the complaint.

1. Parents considered the hoarding as inappropriate. Do you agree/ disagree with their view?
2. What are the methods by which AIDS spreads?
3. What is AIDS?
4. What values are promoted by the children protesting against their parents?

Explain the inheritance of haemophilia of normal man and hemophilic women.

Briefly explain IVF and ET. What are the conditions in which these methods are advised?

Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?

Name the fluid which protects an embryo.

In pea plants, the colour of the flower is either violet or white, whereas human skin colour shows many gradations. Explain giving reasons, how it is possible.

Whose theory was put to test by Miller and Urey and what was the theory? How did their experiment give due to abiotic origin of life on earth?

Gene A, B, C and D are linked. By carrying breeding experiment and recording offspring phenotype the following cross over frequencies are determined.

What is the order of the genes on the linkage map?

Draw a well labelled diagram of sectional view of ovary showing different stages of graafian follicle.

Explain Hershey - Chase experiment. What was proved through this experiments?