Q. No.Select the two correct statements out of the four (a-d) given below about lac operon:
(a)
Glucose or galactose may bind with the repressor and inactivate it.
(b)
In the absence of lactose, the repressor binds with the operator region.
(c)
The z-gene codes for permease.
(d)
It was explained by Francois Jacob and Jacque Monod.
The correct statements are:
1. (b) and (c)
2. (a) and (c)
3. (b) and (d)
4. (a) and (b)
Which one of the following is used as a vector for cloning genes into higher organisms?
1. Baculovirus
2. Salmonella typhimurium
3. Rhizopus nigricans
4. Retrovirus
The one aspect which is not a salient feature of genetic code, is its being:
1. degenerate
2. ambiguous
3. universal
4. specific
DNA or RNA segment tagged with a radioactive molecule is called:
| 1. | vector | 2. | probe |
| 3. | clone | 4. | plasmid |
Satellite DNA is a useful tool in:
1. Organ transplantation
2. Sex determination
3. Forensic science
4. Genetic engineering
Which one of the following does not follow the central dogma of molecular biology?
1. Pea
2. Mucor
3. Chlamydomonas
4. HIV
Whose experiments cracked the DNA and discovered unequivocally that a genetic code is a triplet?
1. Nirenberg and Matthaei
2. Hershey and Chase
3. Morgan and Sturtevant
4. Beadle and Tatum
Semiconservative replication of DNA was first demonstrated in:
1. Drosophila melanogaster
2. Escherichia coli
3. Streptococcus pneumoniae
4. Salmonella typhimurium
What is not true for genetic code?
| 1. | A codon in mRNA is read in non-contiguous fashion |
| 2. | It is nearly universal |
| 3. | It is degenerate |
| 4. | It is unambiguous |
| 1. | The total amount of purine nucleotides and pyrimidine nucleotides is not always equal |
| 2. | There are two strands, which run parallel in the 5' → 3’ direction |
| 3. | The proportion of adenine in relation to thymine varies with the organism |
| 4. | There are two strands, which run antiparallel - one in 5' → 3’ direction and the other in 3’→ 5’ |
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