Human Reproduction — BIOLOGY STD 12 Science — Question

What are antibiotics? Name the classes of organisms that produce antibiotics

Given below is a graph depicting organismic response to changing external conditions. According to their response the organisms are grouped into two types. Name the type which will show (i) Pattern A (ii) Pattern B.

i. How does mutation occur?
ii. Differentiate between point mutation and frameshift mutation.

How was it concluded that genes are located on chromosomes?

Haemophilia is a sex-linked recessive disorder of humans. The pedigree chart given below shows the inheritance of haemophilia in one family. Study the pattern of inheritance and answer the questions given.

1. Give all the possible genotypes of the members 4; 5 and 6 in the pedigree chart.
2. A blood test shows that the individual 14 is a carrier of haemophilia. The member numbered 15 has recently married the member numbered 14. What is the probability that their first child will be a haemophilia male?

What is artificial selection? Do you think it affects the process of natural selection? How?

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.
Why in your opinion the female partner is often blamed for such situations in India?

Write the differences between wind-pollinated and insect-pollinated flowers. Give an example of each type.

Describe the effects of malaria on the human body.

Correct the following statements:

1. Surgical methods of contraception prevent gamete formation.
2. All sexually transmitted diseases are completely curable.
3. Oral pills are very popular contraceptives among the rural women.
4. In E. T. techniques, embryos are always transferred into the uterus.