In the genetic code dictionary, how many codons are used to code for all the 20 essential amino acids:
1. 20
2. 64
3. 61
4. 60
What does "lac" refer to in what we call the lac operon:
1. Lactose
2. Lactase
3. Lac insect
4. The number 1,00,000
Degeneration of a genetic code is attributed to the:
1. First member of a codon
2. Second member of a codon
3. Entire codon
4. Third member of a codon
During transcription, the DNA site at which RNA polymerase binds is called:
1. Promoter
2. Regulator
3. Receptor
4. Enhancer
What would happen if in a gene encoding a polypeptide of 50 amino acids, the 25th codon (UAU) is mutated to UAA?
1. | A polypeptide of 25 amino acids will be formed |
2. | Two polypeptides of 24 and 25 amino acids will be formed |
3. | A polypeptide of 49 amino acids will be formed |
4. | A polypeptide of 25 amino acids will be formed |
Which one of the following triplet codes, is correctly matched with its specificity for an amino acid in protein synthesis or as a 'start' or 'stop' codon:
1. UCG – Start
2. UUU – Stop
3. UGU – Leucine
4. UAC – Tyrosine
In Negative operon:
1. Inducer binds with repressor
2. Co-repressor does not bind with repressor
3. Corepressor binds with inducer
4. CAMP has a negative effect on the lac operon
Due to the discovery of which of the following in 1980, the evolution was termed as RNA world?
1. | m-RNA, t-RNA- rRNA synthesize proteins |
2. | In some viruses, RNA is the genetic material |
3. | RNA has enzymatic property |
4. | RNA is not found in all cells |
E. Coli about to replicate was placed in a medium containing radioactive thymidine for five minutes. Then, it was made to replicate in a normal medium. Which of the following observation shall be correct?
1. | Both strands of DNA will be radioactive |
2. | One strand is radioactive |
3. | Each strand is half radioactive |
4. | None is radioactive |
Types of RNA polymerase required in the nucleus for RNA synthesis:
1. 1
2. 2
3. 3
4. 4