Enhancement of Food Production — BIOLOGY STD 12 Science — Question

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

Given below is a list of six micro-organisms. State their usefulness to humans.

1. Nucleopolyhedrovirus.
2. Saccharomyces cerevisiae.
3. Monascus purpureus.
4. Trichoderma polysporum.
5. Penicillium notatum.
6. Propionibacterium sharmanii.

A vector is engineered with three features, which facilitates its cloning within host cell. List three features and explain each one of them.

Draw a labelled diagram of a cross section through a small part of seminiferous tubule of testis to show some stages of spermatogenesis.
OR
Draw a labelled diagram of the sectional view of a human seminifierous tubule. (Six parts to be labelled).

1. Why did Hershey and Chase use radioactive sulphur and radioactive phosphorus in their experiment?
2. Write the conclusion they arrived at and how.

Two children, A and B aged 4 and 5 years respectively visited a hospital with a similar genetic disorder. The girl A was provided enzyme-replacement therapy and was advised to revisit periodically for further treatment. The girl, B was, however, given a therapy that did not require revisit for further treatment.

1. Name the ailments the two girls were suffering from?
2. Why did the treatment provided to girl A required repeated visits?
3. How was the girl B cured permanently?

Draw a labelled schematic sketch of replication fork of DNA. Explain the role of the enzymes involved in DNA replication.

1. What does this diagrammatic sketch depict?
2. Identify 'a' and 'b'.
3. Name the widely used diagnostic test when a person gets this disease.

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

A farmer while working on his farm was bitten by a poisonous snake. The workers in the farm immediately rushed him to the nearby health centre. The doctor right away gave him an injection to save his life. What did the doctor inject and why? Explain.