Molecular Basis Of Inheritance Question 129

Question: Chargaff’s rules of base pairing states that:

Options:

A) The ratio of purines to pyrimidines is roughly equal in all tested organisms.

B) The ratio of A to T is roughly equal in all tested organisms.

C) The ratio of A + T and G + C is roughly equal in all tested organisms.

D) Both [a] and [b]

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Answer:

Correct Answer: D

Solution:

[d] Chargaff found that the relative ratios of purine to pyrimidines were equal.

Adenine and guanine are purines and cytosine and thymine are pyrimidines; therefore, ratios of adenine and thymine should be equal.

Chargaff also found that there is no conserved ratio between specific pairs ( $ e.g.,A+TandG+c $ ).