Q. No.The nitrogenous bases purines and pyrimidines basically differ in that:
1.
The former is found in RNA while the latter is found in DNA.
2.
The latter is found in RNA while the former is found in DNA.
3.
The former contains a double-ring backbone, while the latter contains a single-ring backbone.
4.
The latter contains a double-ring backbone while the former contains a single-ring backbone.
Identify the correct statements regarding a replisome:
| I: | It is a complex of several proteins. |
| II: | It includes enzymes like DNA polymerase, DNA helicase, and primase. |
| III: | It is found at the replication fork during DNA synthesis. |
| 1. | I and II only | 2. | I and III only |
| 3. | II and III only | 4. | I, II, and III |
The basic difference between the two key enzymes, DNA pol III and DNA ligase, required for DNA replication is:
| 1. | Only DNA pol III synthesizes phosphoester bonds. |
| 2. | Only DNA ligase synthesizes phosphoester bonds. |
| 3. | DNA pol III can synthesize DNA from 3'-5'. |
| 4. | DNA ligase can use energy from ATP rather than nucleotides. |
In which models of DNA replication In this model the two parental DNA strands are back together after replication has occurred?
1. Conservative model.
2. Semiconservative model.
3. Dispersive model.
4. Destructive model.
If a bacterial cell were to contain 4 nucleoids per cell, the number of copies of the bacterial chromosome present in each cell will most likely be:
1. 1
2. 2
3. 3
4. 4
Lagging strand is replicated in a discontinuous manner in small Okazaki fragments because:
| 1. | DNA polymerase cannot synthesize large stretches of DNA. |
| 2. | DNA polymerase needs to be replaced every 1000-2000 nucleotide. |
| 3. | DNA polymerase requires a free 3' OH group to attach new nucleotides. |
| 4. | Only one DNA strand can be used as the template at a time |
The lagging strand and the leading strand during DNA replication are replicated differently because:
1. On the leading strand, DNA synthesis occurs 5' to 3' on the leading strand, while on the lagging strand it is 3' to 5'.
2. DNA polymerase is able to continuously add new nucleotides on the leading strand while it must keep 'starting over' on the lagging strand.
3. The lagging strand requires only a single primer while the leading strand requires many.
4. Helicase opens the leading strand at a faster rate than the lagging strand.
The origin of replication is a particular sequence in a genome at which replication is initiated. This region is AT-rich because:
| 1. | DnaA proteins bind to AT-rich sites. |
| 2. | DnaC proteins bind to AT-rich sites. |
| 3. | AT base pairs are more easily separated than GC base pairs. |
| 4. | AT base pairs contain more hydrogen bonds than GC base pairs. |
A cis acting factor that place very important role in eukaryotic transcription will be:
1. RNA polymerase II.
2. Transcription factors.
3. Enhancers.
4. Shine Dalgarno sequence
The biochemical evidence for the fact that genetic code is a triplet code and read in a contiguous manner is:
| 1. | Insertions or deletions caused significant defects in the protein structure. |
| 2. | The effect of single insertions could be remedied by single deletions nearby. |
| 3. | Two nearby insertions caused significant defects in protein structure. |
| 4. | Three insertions near each other often led to minor defects in protein structure. |
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