Human Reproduction — BIOLOGY STD 12 Science — Question

A true breeding homozygous pea plant with green pods and axial flowers as dominant characters, is crossed with a recessive homozygous pea plant with yellow pods and terminal flowers. Work out the cross up to F₂ generation giving the phenotypic ratios of F₁ and F₂ generation respectively.

What is Pulse Polio Programme of Government of India? What is OPV? Why is it that India is yet to eradicate Polio?

Explain the development of a secondary oocyte (ovum) in a human female from the embryonic stage upto its ovulation. Name the hormones involved in this process.

OR

When does oogenesis start in humans? Name the three hormones and their sources, linked with oogenesis. How do they influence the process of oogenesis? Explain.

1. Explain the role of regulatory gene, operator, promoter and structural genes in lac operon, when E.coli is growing in a culture medium with the source of energy as lactose.
2. Mention what would happen, if lactose is withdrawn from the culture medium.

OR

Describe how the lac operon operates both in the presence and absence of an inducer in E.coli.

What is geitonogamy? Give an example. How does geitonogamy differ from xenogamy in plants?

List 10 modern day animals and using the various resources available link it to a corresponding ancient fossil. Name both of them.

What is rDNA? Explain the technique of cloning rDNA.

What is ecological succession? What is climax community? How is climax community established?

Give reasons for the following:

1. Shivering in malaria.
2. Plasmodium is considered a digenetic parasite.
3. Dengue fever is also known as break bone fever.
4. Swelling of lower limbs in filariasis.

Explain the process of protein synthesis from processed mRNA.