Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Read the following and answer any four questions from (i) to (v) given below:
In testis, the immature male germ cells produce sperms by spermatogenesis that begins at puberty. It occurs in the seminiferous tubules of the testes. Seminiferous tubules are lined by germinal epithelium. Study the schematic representation of spermatogenesis and answer the following questions.

1. Which cell division occurs during multiplication phase?

1. Mitosis.
2. Meiosis I.
3. Meiosis II.
4. Both (b) and (c).

2. How many chromosomes are present in secondary spermatocyte and spermatid, respectively?

1. 46, 23
2. 46, 46
3. 23, 23
4. 23, XY

3. Transformation of L into M is known as:

1. Spermiation.
2. Spermateliosis.
3. Spermatogenesis.
4. None of these.

4. Select the correct option.

1. Type A spermatogonia grows to larger primary spermatocyte.
2. One spermatogonium forms two spermatids.
3. Spenniation is the release of sperms from seminiferous tubules.
4. Primary spermatocyte undergoes mitosis to form secondary spermatocytes.

5. Which hormone acts on spermatogonia to stimulate sperm production?

1. LH.
2. GnRH.
3. ABP.
4. FSH.

What is chromosomal disorder? Explain any two aneuploidy with characters in humans.###Mention any two autosomal genetic disorders with their symptoms.

Read the following and answer any four questions from (i) to (v) given below:
RNA or ribonucleic acid is a single chain polyribonucleotide which functions as carrier of coded genetic or hereditary information from DNA to cytoplasm for taking part in protein and enzyme synthesis. Six types of RNAs are ribosomal, transfer, messenger, genomic, small nuclear and small cytoplasmic RNA. Out of these, rRNA, mRNA and tRNA are major classes of RNAs that are involved in gene expression.

1. Which one is referred to a soluble RNA?

1. mRNA
2. tRNA
3. rRNA
4. hnRNA

2. The RNA that picks up specific amino acid from amino acid pool in the cytoplasm to ribosome during protein synthesis is?

1. rRNA
2. hnRNA
3. mRNA
4. tRNA

3. Which of the following is found in both DNA and messenger RNA?

1. Double helix structure
2. Ribose
3. Sugar-phosphate chain
4. Thymine

4. Which of the following statements regarding RNA is correct?

1. Messenger RN As carries coded information for synthesis of polypeptide.
2. Ribosomal RNAs bind with tRNA to catalyse the formation of phosphodiester bonds.
3. Genomic RNA is always single stranded.
4. Synthesis of rRNA occurs in cytoplasm by RNA polymerase III

5. In studying a virus, you find the following proportions of nitrogenous bases present: adenine 23%, guanine 37%, cytosine 23% uracil 17%. Which of the following statement(s) regarding this virus is/are correct?

1. It probably uses RNA as its genetic material.
2. The genetic material of this virus is probably single stranded.
3. Base pairing rules in virus in this virus include adenine: cytosine.

1. I only
2. I and II only
3. II and III only
4. All of these.

Read the following and answer any four questions from (i) to (v) given below:

A young couple married for 5 years is unable to bear a child in spite of not practicing any birth control method. Upon consultation, doctor advised them an assisted reproductive technology involving transfer of gametes into oviducts.

1. Identify the technique adopted by the couple.

1. ZIFT
2. JUI
3. GIFT
4. ICSI

2. What is the pre-requisite of this technique?

1. Gamete formation should be normal.
2. Fallopian tubes should be normal.
3. Female should have thick endometrial lining.
4. Male should be able to copulate the female.

3. Assertion: GIFT is an in-vitro fertilisation technique.

Reason: In GIFT, gametes are fertilised outside the female body.

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.

4. The procedure advised to couple involves the transfer of:

1. Fertilised ovum.
2. Embryo with 8 blastomeres.
3. Sperms and unfertilised ovum.
4. Embryo with 16 blastomeres.

5. What is the success rate of this procedure?

1. 30-50%
2. < 20%
3. 80-85%
4. 27-30%

Explain with diagram - Hershey and Chase experiment.###On the basis of experimental proof explain the diagram that DNA is genetic material.###How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?

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.

Explain bioreactor with diagram.

Explain- Restriction enzymes.

The bacterium Bacillus thuringiensis is widely used in contemporary biology as:

1. Agent for production of dairy products.
2. Source of industrial enzyme.
3. Indicator of water pollution.
4. Insecticide.