How many of the given features will be true for of the double-helix structure of DNA?
I: It is made of two polynucleotide chains
II: The backbone is constituted by sugar-phosphate
III: The two chains have anti-parallel polarity.
IV: The bases in two strands are paired through hydrogen bonds (H-bonds) forming base pairs (bp)
1. 1
2. 2
3. 3
4. 4

Subtopic:  DNA Double Helix |
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A hypothetical dsDNA of 100 bp length molecule was found to be composed of 40 Adenine residues. The total number of hydrogen bonds in all base pairs of this molecule is expected to be:
1. 100
2. 130
3. 260
4. 300
Subtopic:  DNA Double Helix |
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Consider the given two statements:
Assertion: The distance between a bp in a B-DNA helix is approximately 0.34 nm.
Reason: The pitch of the B-DNA helix is 3.4 nm and there are roughly 10 bp in each turn.
 
1. Both Assertion and Reason are true but Reason does not correctly explain the Assertion.
2. Assertion is true but Reason is False.
3. Assertion is false but Reason is True.
4. Both Assertion and Reason are true and Reason correctly explains the Assertion.
Subtopic:  DNA Double Helix |
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Consider the given two statements:
Assertion: Retroviruses are one known exception to the central dogma in molecular biology as proposed by Francis Crick.
Reason: In retroviruses a sequence of nucleotides is copied from an RNA template during the synthesis of a molecule of DNA.
 
1. Both Assertion and Reason are true but Reason does not correctly explain the Assertion.
2. Assertion is true but Reason is False.
3. Assertion is false but Reason is True.
4. Both Assertion and Reason are true and Reason correctly explains the Assertion.
Subtopic:  The DNA |
 72%
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Nucleosome:
I: is formed by the wrapping of negatively charged DNA around the negatively charged histone octamer.
II: typically contains 200 bp of DNA helix.
III: constitutes the repeating unit of a structure in nucleus called chromatin.
IV: is seen as ‘beads-on-string’ structure when viewed under electron microscope (EM).
1. Only I, II and III are correct
2. Only I, III and IV are correct
3. Only II, III and IV are correct
4. I, II, III and IV are correct
Subtopic:  DNA Packaging |
 84%
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Consider the given two statements:
Assertion (A): Euchromatin is said to be transcriptionally active chromatin, whereas heterochromatin is inactive.
Reason (R): Light stained region of chromatin is euchromatin and dark stained region is heterochromatin.
 
1. Both (A) and (R) are True but (R) does not correctly explain (A).
2. (A) is True but (R) is False.
3. (A) is False but (R) is True.
4. Both (A) and (R) are True and (R) correctly explains (A).
Subtopic:  The DNA |
 72%
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All the following can be logical conclusions of Griffith experiment except:
 
1. The R strain bacteria had somehow been transformed by the heat-killed S strain bacteria.
2. Some ‘transforming principle’, transferred from the heat-killed S strain, had enabled the R strain
to synthesise a smooth polysaccharide coat and become virulent.
3. The transformation must be due to the transfer of the genetic material.
4. The biochemical nature of genetic material must be the protein
Subtopic:  Search for Genetic Material: II |
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Regarding Hershey and Chase experiment:
Statement I: Bacteria that were infected with viruses that had radioactive proteins were not radioactive.
Statement II: Proteins did not enter the bacteria from the viruses.
 
1. Statement I is correct; Statement II is incorrect
2. Statement I is incorrect; Statement II is incorrect
3. Statement I is correct; Statement II is correct
4. Statement I is incorrect; Statement II is correct
Subtopic:  Search for Genetic Material: II |
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A molecule that can act as a genetic material should be able to generate its replica (Replication). Therefore:
I: Both the nucleic acids (DNA and RNA) can act as the genetic material.
II: Proteins cannot act as the genetic material.
 
1. Only I is correct
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect
Subtopic:  DNA vs RNA as Genetic Material |
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Consider the given two statements:
Assertion (A): Viruses having RNA genome and having shorter life span mutate and evolve faster.
Reason (R): RNA being unstable, mutates at a faster rate.
 
1. Both (A) and (R) are True but (R) does not correctly explain (A).
2. (A) is True but (R) is False.
3. (A) is False but (R) is True.
4. Both (A) and (R) are True and (R) correctly explains (A).
Subtopic:  DNA vs RNA as Genetic Material |
 83%
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