Q. No.To initiate translation, the mRNA first binds to:
1. The smaller ribosomal sub-unit,
2. The larger ribosomal sub-unit
3. The whole ribosome
4. No such specificity exists.
In E.coli, the lac operon gets switched on when:
1. lactose is present and it binds to the repressor
2. repressor binds to operator
3. RNA polymerase binds to the operator
4. lactose is present and it binds to RNA polymerase
Identify the incorrect statement regarding the comparison of an RNA and a DNA molecule:
| 1. | Both are composed of nucleotides joined by phosphodiester bonds. |
| 2. | Both have secondary and tertiary structures. |
| 3. | RNA is always single-stranded while DNA is always double-stranded. |
| 4. | Both have the same purine bases. |
Griffith wanted to make a vaccine to prevent pneumonia. He injected heat-killed S-strain bacteria into the mice for this purpose. How can a killed bacteria help in making a vaccine?
| 1. | The heat-killed bacteria is a more potent toxin than the live one. |
| 2. | Protein denaturation due to heat changes the proteins of the bacterium. |
| 3. | Molecules from the cell surface are still intact and can provoke an immune response. |
| 4. | DNA molecules can transform other strains of bacteria. |
The functions of the telomeres include:
| I: | They prevent chromosomes from fusing with each other. |
| II: | They prevent chromosomes from shrinking due to DNA loss during replication. |
| III: | They allow chromosomes to segregate properly during cell division. |
| 1. | I and II only |
| 2. | I and III only |
| 3. | II and III only |
| 4. | I, II, and III |
The two strains, R and S, of the bacterium Streptococcus pneumoniae, differ as:
| 1. | Rough bacteria can evade the immune system of a mouse. |
| 2. | Rough bacteria do not have most genes present in smooth bacteria. |
| 3. | Smooth bacteria do not have most genes present in rough bacteria. |
| 4. | Smooth bacteria are able to synthesize a polysaccharide capsule. |
Packaging of DNA ensures:
| 1. | Very long molecules of DNA can be packed into a small space. |
| 2. | Information within DNA is made available to drive cellular functions. |
| 3. | Information within DNA is modified from generation to generation. |
| 4. | All genes are transcribed. |
Deoxyribonucleotides in a ds DNA are held by:
I. Phosphodiester.
II. Hydrogen.
III. Ionic.
1. I and II only
2. I and III only
3. II and III only
4. I, II and III
Griffith's experiment discovered bacterial transformation which in his experiment means:
| 1. | A mutation in the R strain made them virulent. |
| 2. | A mutation in the S strain made them non-virulent. |
| 3. | A rough strain passed genetic information to a smooth strain. |
| 4. | A smooth strain passed genetic information to a rough strain. |
All the following will not be applicable to DNA replication in prokaryotes except:
1. It begins at several places along the chromosome.
2. It begins at the origin and travels in both directions.
3. It begins at the origin and travels around the chromosome back to the origin.
4. It begins at a GC rich region of the chromosome.
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