Human Reproduction — BIOLOGY STD 12 Science — Question

List the advantages of recombinant insulin.

For selection of recombinants, insertional inactivation of antibiotic marker has been superceded by insertional inactivation of a marker gene coding for a chormogenic substrate. Give reasons.

Answer the following questions:
How did Morgan show the deviation in inheritance pattern in Drosophila with respect to this law?

Read the following and answer any four questions from (i) to (v) given below:

Transgenic animals can serve as factories that in some cases, may produce large amount of proteins more efficiently. Transgenic mice have been engineered to express human antibodies by introducing large segment of human DNA encoding human immunoglobulin genes. In transgenic large animals such as cow or sheep proteins of pharmaceutical value can be produced in large quantities in milk which is later purified. Transgenesis can be used to alter many phenotypic properties including growth rate, fat composition, milk production, hair texture, etc.

1. The production of transgenic animals includes

1. Identification and separation of desired gene.
2. Combining the desired gene with appropriate vector.
3. Introduction of vector in cells, tissues or embryos.
4. All of these.

2. In transgenic animals, i.e., cow and sheep proteins of pharmaceutical value are produced in large quantities in the

1. Blood.
2. Accumulated fat.
3. Mammary glands.
4. None of these.

3. Mouse is mostly preferred animal for studies on gene transfer because.

1.  Short oestrous cycle.
2. Long gestation period.
3. Short generation time.
4. Production of one or two offspring per pregnancy.

1. Both (A) and (C)
2. Both (A) and (B)
3. Only D
4. Both (C) and (D).

4. Transgenic genes alter many phenotypic properties including:

1. Growth rate.
2. Fat composition.
3. Milk production.
4. All of these.

5. Assertion: Transgenic mice have been engineered to express human antibodies.

Reason: Large segment of human DNA encoding human immunoglobulin have been transferred to mice.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

(i) Define the cross-pollination.
(ii) Give one example each of aluminious, exalbuminous, perispermic seeds.
(iii) Draw a well labelled diagram showing the growth of pollen tube in longitudinal section of pistil.

Pragyan takes fruits, vegetables, bread and egg curry in a day's menu. While his teacher was giving a lecture on trophic level, he got fascinated and asked following questions from his teacher.

1. How many trophic levels does he occupy in different food chains?
2. Represent atleast three food chains.
3. Which among them gives him the maximum amount of energy? Give reason.
4. What values are shown by Pragyan?

1. How is artificial hybridisation considered a crop improvement programme?
2. Explain the process of artificial hybridisation, if

1. Female parent bears bisexual flowers.
2. Female parent bears unisexual flowers.

What is oogenesis? Give a brief account of oogenesis.

What is cancer? Write the main types of cancer. Name at least three deadly signs of cancer.

How is sex determined in human beings?