Human Health and Disease — BIOLOGY STD 12 Science — Question

1. Write two differences between Homo erectus and Homo habilis.
2. Rearrange the following from early to late geologic periods:

Carboniferous, Silurian, Jurassic.

1. Name the tropical sugar cane variety grown in South India. How has it helped in improving the sugar cane quality grown in North India?
2. Identify ‘a’, ‘b’ and ‘c’ in the following table:

No.	Crop	Variety	Insect Pests
1.	Brassica	Pusa Gaurav	(a)
2.	Flat bean	Pusa Sem 2, Pusa Sem 3	(b)
3.	(c)	Pusa Sawani, Pusa A-4	Shoot and fruit borer

1. Trace the development of an endosperm after fertilisation with reference to coconut. Mention the importance of endosperm development.
2. Write the importance of 'pollen bank'.

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?

1. Describe the endosperm development in coconut.
2. Why is tender coconut considered a healthy source of nutrition?
3. How are pea seeds different from castor seeds with respect to endosperm?

What are 'cloning sites' in a cloning vector? Explain their role. Name any two sites in pBR 322.

The diagram shows a part of the human female reproductive system.

1. Name the gamete cells that would be present in 'X', if taken from a newborn baby.
2. Name 'Y' and write its function.
3. Name 'Z' and write the events that take placehere.

What is a connecting link? Give suitable examples of connecting links.

Discuss the significance of heavy isotope of nitrogen in the Meselson and Stahl’s experiment.