Human Reproduction — BIOLOGY STD 12 Science — Question

What is floriculture? Describe the structure of a stamen. Also draw a well labelled diagram of a typical stamen.

Answer the following questions:

Given below is the T.S. of human ovary. Identify the following in the diagram:

1. Corpus luteum.
2. Secondary oocyte.
3. Antrum.
4. Primary follicle.
5. Blood vessels.

Which vectors can be used to clone a fragment of DNA with the following lengths?

1. 4Kb
2. 35Kb
3. 20Kb
4. 250Kb

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.

Answer the following questions:
You are given tall pea plants with yellow seeds whose genotypes are unknown. How would you find the genotype of these plants? Explain with the help of cross.

Raj was a known sportsman in his school. While returning home he found some unknown miscreants beating a young fellow. He tried to drive them off, but by that time the fellow died of injury. The police arrested Raj and he was put on trial. The judge being convinced by Raj's plea, ordered for DNA fingerprinting reports.

1. What is the basis of DNA fingerprinting?
2. Explain the steps in DNA fingerprinting.
3. Write the applications of DNA fingerprinting.
4. Raj's fingerprints on the dead body were sufficient to convict him but the judge asked for authentic proof. What values can be observed by the judge?

1. Explain the phenomenon of multiple allelism and co-dominance taking ABO blood group as an example,
2. What is the phenotype of the following:

1. I^Ai
2. ii

Write a short note on :
(a) Adaptations of desert plants and animals.
(b) Adaptations of plants to water scarcity.
(c) Behavioural adaptations in animals.
(d) Importance of light to plants.
(e) Effect of temperature or water scarcity and the adaptations of animals.

What are the major causes of species losses in geographical area?

(a) It is supposed that IUDs are effective contraceptive devices. Write names of any two commonly used IUDs and mention their mechanism of action.
(b) When the married couples are advised for sterilization? How it is carried out in male and female humans, respectively?