Human Reproduction — BIOLOGY STD 12 Science — Question

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.

A person has been diagnosed to be HIV positive.

1. Name the test which the person underwent.
2. Write the full name of the pathogen involved and describe its structure.
3. Which particular cells of this person are likely to get destroyed?

Bt cotton is resistant to pest, such as lepidopteron, dipterans and coleopterans. Is Bt cotton also resistant to other pests as well?

Name the genus to which baculoviruses belong. Describe their role in the integrated pest management programmes.

When a cross in made between tall plant with yellow seeds (TtYy) and tall plant with green seed (Ttyy), what proportions of phenotype in the offspring could be expected to be,

1. Tall and green.
2. Dwarf and green.

How does a transgenic organism differ from the rest of its population? Give any two examples of such organism for human advantage.

Differentiate between in situ and ex situ approaches of conserving biodiversity.

1. What is this diagram representing?
2. Name the parts a, band c.
3. In the eukaryotes the DNA molecules are organised within the nucleus.How is the DNA molecule organised in a bacterial cell in absence of a nucleus?

Answer the following questions:
Explain sex determination in humans.

GM Plants are useful in many ways. How would you convince the farmers to grow GM plants in their fields? Explain giving three reasons.

OR

People are quite apprehensive to use GM crops. Give three arguments in support of GM crops so as to convince the people in favour of such crops.