Principles of Inheritance and Variation — BIOLOGY STD 12 Science — Question

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

Following the collision of two trains, a large number of passengers are killed. A majority of them are beyond recognition. Authorities want to hand over the dead to their relatives. Name a modem scientific method and write the procedure that would help in the identification of kinship.

The outline structure of a drug is given below,

1. Which group of drugs does this represent?
2. What are the modes of consumption of these drugs?
3. Name the organ of the body which is affected by consumption of these drugs.

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How does Agrobacterium tumefaciens act as a suitable vector in biotechnology experiments? Cite an example, where it has been successfully used as a vector.

Describe three manners in which fertilisation of human ovum by a sperm can be prevented.

Explain the mechanism of ‘sex determination’ in birds. How does it differ from that of human beings?

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?

Describe sex-determination in birds with example.

How do ‘pills’ act as contraceptives in human female?

Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher.