Q. No.Ten E.coli cells with \({ }^{15} \mathrm{~N}\) - ds DNA are incubated in medium containing \({ }^{14} \mathrm{~N}\) nucleotide. After 60 minutes, how many E.coli cells will have DNA totally free from \({ }^{15} \mathrm{~N}\) ?
1. 80 cells
2. 20 cells
3. 40 cells
4. 60 cells
Which one of the following is not a criterion of genetic material?
| 1. | Should not provide the scope for changes for evolution |
| 2. | Should be able to express itself in the form of Mendelian character |
| 3. | Should be able to generate its replica |
| 4. | Should be stable chemically and structurally |
DNA replication is semi-conservative in nature was experimentally proved in eukaryotes by:
1. Hershey and Chase
2. Macleod and McCarty
3. Meselson and Stahl
4. Talyor and his colleagues
Which one of the following experiments of Frederick Griffith resulted in the discovery of bacterial transformation?
| 1. | S-stain(heat-killed) → injected in to Mice → Mice lived |
| 2. | S-strain (heat killed) + R-strain(live) → injected in to Mice → Mice died |
| 3. | S-stain → injected in to Mice → Mice died |
| 4. | R-strain → injected in to Mice → Mice lived |
Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R)
| Assertion (A): | Semiconservative replication was experimentally proved by Mathew Meselson and Franklin Stahl (1958) |
| Reason (R): | Meselson and Stahl used radioactive isotope \(^{15}N\) and equilibrium density gradient centrifugation technique. |
In the light of the above statements, choose the correct answer from the options given below:
| 1. | (A) is correct but (R) is not correct. |
| 2. | (A) is not correct but (R) is correct. |
| 3. | Both (A) and (R) are correct and (R) is the correct explanation of (A). |
| 4. | Both (A) and (R) are correct but (R) is not the correct explanation of (A). |
With respect to nucleosome, Which of the following statements is incorrect ?
| 1. | Nucleosome contains 120 bp of DNA helix. |
| 2. | Nucleosomes are seen as 'beads' on string' under Electron Microscope. |
| 3. | DNA is wrapped around positively charged histone octamer to form nucleosome. |
| 4. | Nucleosome is the repeating unit of chromatin. |
One of the strands of double stranded DNA has base composition as follows: 15% A, 15% T, 40%G and 30%C. What will be the percentage of these bases in the complementary strand ?
1. 15% A, 15% T, 30% G , 40% C
2. 15% A, 30% T, 40% G , 15% C
3. 15% A, 15% T, 40% G , 30% C
4. 15% A, 40% T, 15% G , 30% C
What would be the proportions of light and hybrid density DNA molecule, respectively if Meselson and Stahl's experiment was continued for 60 minutes?
1. 50%, 50%
2. 25%, 75%
3. 75%, 25%
4. 100%, 0%
1. 1
2. 3
3. 2.5
4. 2
1. Eukaryotic mRNAs get 5' caps and 3' tails.
2. Prokaryotic genes are expressed as mRNA, which is more stable in the cell.
3. Eukaryotic exons may be spliced in alternative patterns.
4. Prokaryotes use ribosomes of different structure and size
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