Question Bank [2022] — BIOLOGY STD 12 Science — Question

The diagram above is that of a typical biogas plant.Explain the sequence of events occurring in a biogas plant. Identify a, b and c.

On his visit to a national park, Harshendra was very angry as the forest authorities did not allow him to enter a specified area. On returning back, he discussed the matter with his friend, who explained him the reason.

1. Which category of conservation strategy does national park belong?
2. Name India's first national park.
3. At present, there are how many national parks in India?
4. What values are shown by Harshendra's friend?

Name the stage of human embryo at which it gets implanted. Explain the process of implantation.

Answer the following questions:
Mention the problems that are taken care of by Reproduction and Child Health Care programme.

A red–eyed heterozygous female fruit fly is crossed with a red–eyed male. Work out all possible genotypes and phenotypes of the progeny. Comment on the pattern of inheritance of eye colour in fruit flies.

Given below is the representation of amino acid composition of the relevant translated portion of B-chain of haemoglobin, related to the shape of human red blood cells.

1. Is this representation indicating a normal human or a sufferer from certain related genetic disease? Give reason in support of your answer.
2. What difference would be noticed in the phenotype of the normal and the sufferer related to this gene?
3. Who are likely to suffer more from the defect related to the gene representedthe males, the females or both males and females equally? And why?

What is pregnancy hormone? Why is it so called? Name two sources of this hormone in a human female.

Give reasons : Pericardium acts as a defence wall for the heart.

Complete the following model of carbon cycle by filling A, B, C, D, E and F.

The cytological observations made in a number of insects led to the development of the concept of genetic/ chromosomal basis of sex-determination mechanism. Honey bee is an interesting example to study the mechanism of sex-determination. Study the schematic cross between the male and the female honey bees given below and answer the questions that follow:

1. Identify the cell divisions ‘A’ and ‘B’ that lead to gamete formation in female and male honey bees respectively.
2. Name the process ‘C’ that leads to the development of male honey bee (drone).