Organisms and Populations — BIOLOGY STD 12 Science — Question

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.

Read the following and answer any four questions from (i) to (v) given below:
Cleavage is the series of rapid mitotic divisions in zygote and forms blastula. The 2, 4, 8, 16 daughter cells are called blastomeres. Embryo with 64 blastomeres is known as blastocyst and has blastocoel cavity. Blastocyst gets implanted in uterine wall and leads to pregnancy.

1. Solid mass of cells with 16 blastomeres is called:

1. Morula.
2. Blastula.
3. Gastrula.
4. Zygote.

2. At which stage of embryonic development, trophoectoderm develops?

1. Zygote.
2. Morula.
3. Blastula.
4. Gastrula.

3. Site of implantation is:

1. Endometrium of uterus.
2. Cervix.
3. Uterine fundus.
4. Infundibulum of oviduct.

4. Correct sequence of various structures formed during embryonic development is:

1. Morula → Embryo → Gastrula → Blastula.
2. Zygote → Embryo → Morula → Blastula.
3. Blastula → Morula → Gastrula → Embryo.
4. Zygote → Morula → Blastula → Gastrula.

5. Assertion: Side of blastocyst with inner cell mass is called animal pole.

Reason: Inner cell mass gives rise to embryo.

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:
A desert lizard (an ectotherm) and a mouse (an endotherm) are placed inside a chamber at 15ºC and their body temperature [T(L) for the lizard and T(M) for the mouse] and metabolic rates [M(L) for lizard and M(M) for the mouse] are monitored.

1. Which of the following is correct regardingT(L), M(L), T(M) and M(M)?

1. T(L) and M(L) will fall while T(M) and M(M) will increase.
2. T(L) and M(L) will increase while T(M) and M(M) will fall.
3. T(L) and M(L) will fall, T(M) will remain same and M(M) will increase.
4. T(L) and M(L) will remain same, T(M) and M(M) will decrease.

2. It can be said that some animals in their evolutionary development preferred to be ectotherms than endotherms. Which of the following can be the best suited reason for it?

1. The metabolic reactions of these organisms can occur at a very wide range of temperature.
2. Maintaining homeostasis is an energetically expensive process.
3. The enzymes of these organisms are functional at high temperatures.
4. Both (b) and (c).

3. Organisms that can maintain a constant internal temperature are called.

1. Homoeothermic
2. Poikilothermic
3. Oligothennic
4. Heterothennic

4. An animal that survives at temperature of 10ºC and 40ºC both can be placed under the category of:

1. Ectotherm.
2. Endotherm.
3. Modifiers.
4. Migratory organisms.

5. Study the graph carefully and select the correct option.

1. X could be desert lizard.
2. Y could be mouse.
3. Z could be desert lizard.
4. Both (a) and (b).

Distinguish between : Pulmonary circulation and Systemic circulation.

Read the following and answer any four questions from (i) to (v) given below:
While studying inheritance of characters, a teacher gave the example of inheritance of attached earlobe and hypertrichosis of the ear to her students. A man with attached earlobes and extensive hair on pinna married a woman having free earlobes. The couple had four children, one son with attached earlobes and hairy pinna, one son with a free earlobes and hairy pinna and two daughters with attached earlobes. One of the daughters married a man with free earlobes and sparse hair on pinna. Teacher said if this couple would have sons there would be equal chances for both having free or attached earlobes and sparse hair on pinnae.

1. Attached and free earlobe are respective example of?

1. Dominant and recessive traits.
2. Recessive and recessive traits.
3. Recessive and dominant traits.
4. Dominant and dominant traits.

2. Hypertrichosis of the ear is.

1. X linked trait
2. Y linked trait
3. Autosomal dominant trait
4. Autosomal recessive trait.

3. If a female with attached earlobe married a male homozygous for free earlobe sparse hair on pinna then what would be the chances of daughter to have attached earlobe?

1. 0%
2. 100%
3. 25%
4. 75%

4. If a man with attached earlobe and hairy pinna married a woman with attached earlobe then what would be the chances of son to have hairy pinna?

1. 50%
2. 100%
3. 75%
4. 0%

5. A male with attached earlobe, sparse hair on pinna married a female with attached earlobe. Which of the following is correct regarding their progenies?

1. All sons have a free earlobe with hairy pinna.
2. All daughters have an attached earlobe.
3. 50% daughters have an attached earlobe whereas 50% daughters have a free earlobe.
4. 50% sons have attached earlobe with hairy pinna and 50% sons have a free earlobe