Environmental Issues — BIOLOGY STD 12 Science — Question

1. Why are engineered vectors preferred?
2. A vector is engineered with three features, which facilitate its cloning within the host cell. List the three features and explain each one of them.

The graph given below shows the variation in the levels of ovarian hormones during various phases of menstrual cycle:
Identify ‘A’ and ‘B’.

The harmful allele of sickle cell anemia has not been eliminated from human population. Such afflicted people derive some other benefit. Discuss.

How do you express the meaning of words like race, breed, cultivars or variety?

Answer the following questions:
Explain Polygenic inheritance and Multiple allelism with the help of suitable examples.

Do all the gametes formed from a parent organism have the same genetic composition? Analyse the situation with the background of gametogenesis and provide suitable explanation.

Write notes on ex-situ conservation of biodiversity

What are the various advantages of using genetically modified plants to increase the overall yield of the crop?

In which way has the study of biology helped us to control infectious diseases?

No evidence was found on a crime scene, other than only a few hair strands. The inspector wants to proceed for DNA fingerprinting, but the amount of DNA is very less.

1. In your opinion what could be the solution to this problem?
2. Write the basic steps of this technique.
3. Name the scientist who developed this technique.
4. What values shown by the inspector?