Reproductive Health — BIOLOGY STD 12 Science — Question

1.How and at what stage does Plasmodium enter into a human body?

2.With the help of a flow-chart only show the stages of asexual reproduction in the life-cycle of the parasite in the infected an.

3.Why does the victim show symptoms of high fever?

Explain xerarch succession highlighting the xeral communities.

Classify the following as examples of homology and analogy:

1. Mouth parts of cockroach and butterfly.
2. Hearts of rabbits and human beings.
3. Eyes of octopus and mammals.
4. Sweet potato and potato.
5. Stings of honeybee and scorpion.
6. Tendrils of Lathyrus and tendrils of Gloriosa.

Draw a diagram of a male gametophyte of an angiosperm. Label any four parts. Why is sporopollenin considered the most resistant organic material?

1. Why must bacterial cells be first made 'competent' in rDNA technology? How is the process carried out?
2. Name the methods by which an alien DNA can be made to enter:

1. A plant cell.
2. An animal cell.

Draw a labelled sketch of sparged-stirred-tank bioreactor. Write its application.

Bio-fertilisers are organisms that enrich the nutrient quality in the soil. Explain the role of three main sources of bio-fertilisers.

What is LAB? What is its role in human stomach?

Why is Agrobacterium tumefaciens a good cloning vector? Explain.

Agrobacterium tumefaciens is considered as a good cloning vector. Explain why?