Telomere repetitive DNA sequences control the function of eukaryotic chromosomes because they:
1. act as replicons
2. are RNA transcription initiators
3. help chromosome pairing
4. prevent chromosome loss
During transcription, RNA polymerase holoenzyme binds to a gene promoter and assumes a saddle-like structure. What is its DNA-binding sequence?
1. | TIAA | 2. | AATI |
3. | CACC | 4. | TATA |
What would happen if in a gene encoding a polypeptide of 50 amino acids, 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 |
Gene regulation governing lactose operon of E. coli that involves the lac I gene products is:
1. | positive and inducible because it can be induced by lactose. |
2. | negative and inducible because repress or protein prevents transcription. |
3. | negative and repressible because repress or protein prevents transcription. |
4. | feedback inhibition because excess of β galactosidase can switch off transcription. |
Which of the following RNA should be most abundant in an animal cell?
1. | t-RNA | 2. | m-RNA |
3. | mi-RNA | 4. | r-RNA |
During DNA replication, Okazaki fragments are used to elongate:
1. | The lagging strand towards the replication fork. |
2. | The leading strand away from the replication fork. |
3. | The lagging strand away from the replication fork. |
4. | The leading strand towards the replication fork. |
E. coli cells with a mutated z gene of the lac operon cannot grow in a medium containing only lactose as the source of energy because-
1. | They cannot synthesize functional beta-galactosidase |
2. | They cannot transport lactose from the medium into the cell |
3. | The lac operon is constitutively active in these cells |
4. | In the presence of glucose, E. coli cells do not utilize lactose |
I: | Griffith discovered the process of bacterial transformation. |
II: | Hershey and Chase unequivocally proved that DNA is the genetic material. |
III: | Meselson and Stahl showed that DNA replicated semi-conservatively. |
1. | Only I and II are correct |
2. | Only I and III are correct |
3. | Only II and III are correct |
4. | I, II and III are correct |
I: | Capping is done at the 5’ end and tailing at the 3’ end |
II: | Exons are removed from the split gene to form the cistron |
1. | Only I is correct |
2. | Only II is correct |
3. | Both I and II are correct |
4. | Both I and II are incorrect |
I: | a polycistronic structural gene is regulated by a common promoter and regulatory genes |
II: | the regulation is always negative and inducible |
1. | Only I is correct |
2. | Only II is correct |
3. | Both I and II are correct |
4. | Both I and II are incorrect |