Plant Water Relation — BIOLOGY STD 12 Science — Question

Polymerase chain reaction:

1. Is a method of synthesising human protein from human DNA
2. Uses restriction enzymes
3. Can produce billions of copies of a DNA fragment
4. Takes place naturally in bacteria

Distinguish between: Blastula and Gastrula ### Give two differences between blastula and gastrula.

What is meant by chromosomal mutation?

Read the following and answer any four questions from (i) to (v) given below:
Human male reproductive system comprises of a pair of testes, primary sex organs associated with formation of gametes and production of sex hormone. Study the given figure of human male reproductive system and answer the following questions.

1. Which of the following is correct for labelled part P?

1. P is rete testis which transports sperms to outside.
2. P is epididymis which secretes fluid that nourish the sperms.
3. P is epididymis that carry sperms and secretion of seminal vesicles.
4. P is rete testis, which lies along inner side of each testis and stores the sperms.

2. Identify the correctly matched pair.

1. Q - Vasa efferentia.
2. R - Ejaculatory duct.
3. S - Seminal vesicle.
4. T - Cowper's gland.

3. Which statement is incorrect for Q?

1. It carries spermatozoa from epididymis to ejaculatory duct.
2. Q are only 2 in number.
3. It arises from rete testis.
4. It constitutes male sex accessory duct.

4. Which structure passes through the prostate gland and carries sperms and secretion of seminal vesicle?

1. P.
2. T.
3. S.
4. R.

5. Assertion: Mucus present in secretion of bulbourethral gland decreases the number of sperms damaged during ejaculation.

Reason: Mucus lubricates the end of penis and lining of the urethra.

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.

Read the following and answer any four questions from (i) to (v) given below:
Green manuring is the fanning practice where a leguminous plant which has derived enough benefits from its association with appropriate species of Rhizobium, is ploughed into the field soil and then a non-legume is sown and allowed to get benefitted from the already present nitrogen fixer. Some legumes, such as, Crotolaria juncea, Sesbania rostrata, Lencaena leucocephala, etc. are used as green manure. Rhizobia, that fix atmospheric nitrogen in the form of nitrate, live in the roots ofleguminous plants. These nutrients are used by non-leguminous plants through the practice of green manuring.

1. Green manures mainly provide nutrient enriched in:

1. Magnesium.
2. Sulphur.
3. Nitrogen.
4. Both (a) and (b).

2. Which of the following plants is used as green manure in crop fields?

1. Saccharum.
2. Dichanthium.
3. Phyllonthus.
4. Crotolaria.

3. Green manure plants belong to the Family:

1. Lamiaceae.
2. Papilionaceae.
3. Liliaceae.
4. Poaceae.

4. Due to excess use of chemical fertilisers rich in nitrate, ________ disease occurred in children.

1. Jaundice.
2. Septicemia.
3. Methemoglobinemia.
4. Botulism.

5. A green manure is:

1. Rice.
2. Maize.
3. Sorghum.
4. Sesbania.

Read the following and answer any four questions from (i) to (v) given below:
Gene manipulation is a fast emerging science. It started with development of recombinant DNA molecule. It is named variously as DNA manipulation biotechnology, recombinant DNA technology and genetic engineering. This technology, that mostly involves cutting and pasting of desired DNA fragments, is based on two important discoveries in bacteria, i.e., presence of plasmid in bacteria and restriction endonucleases. Paul Berg was able to introduce a gene ofSV-40 into a bacterium. The science of recombinant DNA technology took birth when Cohen and Boyer (1973) were able to introduce a piece of gene containing foreign DNA into plasmid of E.coli.

1. Biotechnology is also known as:

1. DNA manipulation biotechnology.
2. Recombinant DNA technology.
3. Genetic engineering.
4. All of these.

2. A bacterial plasmid is a/ an,

1. Extra chromosomal material that do not replicate.
2. Extra chromosomal material that undergo replication with or without chromosomal DNA.
3. Tubular structures that help in conjugation.
4. Bristle like solid structure that help in adhesion.

3. Father of genetic engineering is:

1. Paul Berg.
2. Arber.
3. Nathan.
4. Smith.

4. Which of the following is used by Paul Berg to introduce a gene of SV-40 in a bacterium?

1. E. coli.
2. cos-plasmids.
3. Lambda phage.
4. None of these.

5. Read the given statements and select the correct option.

Assertion: Biotechnology started with the development of recombinant DNA molecule.

Reason: Biotechnology mostly involves cutting and pasting of desired DNA fragments.

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.

Distinguish between : Granulocytes and Agranulocytes.

Outcrossing and Crossbreeding.