Respiration and Circulation — BIOLOGY STD 12 Science — Question

Read the following and answer any four questions from (i) to (v) given below:
Tools used in the formation of recombinant DNA are of three types. These are enzymes, cloning vectors and competent host. lysing enzymes are used to extract DNA for experimental purpose from the cells. Cleaving enzymes break the DNA molecules. TI1ey are of three types : exonucleases, endonucleases and restriction endonucleases. A competent host is required for transformation with recombinant DNA and cloning vectors help to propagate DNA.

1. Which of the following is an example of natural Iysing activity in a human body?

1. Lysozyme present in tears dissolve the bacterial cell wall.
2. Conversion of starch to maltose in the buccal cavity
3. Absorption of digested food into the intestinal cells.
4. Conversion of protein molecules into amino acids in the stomach.

2. Which of the following depicts exonuclease activity?

1.  

2.  

3.  

4. All of these

3. Cloning vectors are the DNA molecules that.

1. Carry foreign DNA segment but do not replicate inside the host cell.
2. Carry foreign DNA segment and replicate inside the host cell.
3. Transfer nuclear DNA form nucleus to the cytoplasm of the same cells.
4. Help in sealing gaps in DNA segments.

4. Transfer of DNA into a eucaryotic cell is called:

1. Transformation.
2. Transduction.
3. Transfection.
4. Electroporation.

5. Assertion: Type I restriction enzymes are not used in rDNA technology.

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: Morula and Blastula.

A patient is suffering from ADA deficiency. Can he be cured? How?

Distinguish between : Ascariasis and Filariasis.

Distinguish between : Electrical and chemical synapses:

Distinguish Between: Monohybrid cross and Dihybrid cross.

Read the following and answer any four questions from (i) to (v) given below:
Oral administration of small doses of hormones is contraceptive method used by the females. They are used in the form of tablets and hence called the pills. The oral pills are two types; mini pills and combined pills.

1. Mini pills contain:

1. Estrogen only.
2. Progestin only.
3. Combination of progesterone-estrogen.
4. Inhibin.

2. How do hormonal pills prevent pregnancy?

1. By phagocytosing the sperms.
2. By inhibiting ovulation.
3. By preventing sperms from entering the vagina.
4. All of these.

3. Pill containing non-steroidal preparation, centchroman is:

1. Mala D.
2. Mala N.
3. I-Pill.
4. Saheli.

4. Which among the following is incorrect for oral contraceptives?

1. Oral pills alter the uterine endometrium and make it unsuitable for implantation.
2. Oral pills have to be taken daily for 7 days starting within first five days of menstrual cycle.
3. Oral pills increase the risk of intravascular clotting.
4. Oral pills contain either progestin alone or combination of progestogen and estrogen.

5. Assertion: Mala D, a combined contraceptive pill, have to be taken daily without a break.

Reason: Mala D contains synthetic progesterone and estrogen.

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.