Biotechnology: Principles and Processes — BIOLOGY STD 12 Science — Question

Explain the contribution of Alfred Sturtevant in ‘Chromosome mapping’.

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.

a. Draw a diagram of a fully developed embryo sac of an angiosperm. Label its chalazal end and any other five parts within the embryo sac.
b. Why does the development of an endosperm precede that of the embryo in angiosperm?
c. Number of chromosomes in an onion plant cell is 16. Name the cells of the embryo sac having 16 and 24 chromosomes formed after fertilisation.

Explain the chromosomal theory of inheritance.

What is called retrovirus? Show the replication of retrovirus with the help of diagram.

Explain the difference between the following :
(i) Nucleoside and nucleotide
(ii) DNA and RNA
(iii) Codon and anticodon
(iv) Transcription and translation
(v) Inductive regulation and inhibitory regulation
(vi) RNA splicing and RNA editing

How does a chromosomal disorder differ from a Mendelian disorder?

List the harmful effects caused by alcohol/drug abuse.

Describe in detail the development of male gametophyte in angiosperms with well labelled diagram.

Write any four ways used to introduce a desired DNA segment into a bacterial cell in recombinant technology experiments.