Question

If you were evaluating double-stranded samples of DNA, which of the following relationships must be true?

a. (A + G)= (T + C)
b. (C + G) =(A + T)
d. a and b
c. (A + C) =(T + G)
e. a and c

Answer 1

The correct relationships for evaluating double-stranded DNA are based on Chargaff's rules: (A + G) = (T + C), and (C + G) = (A + T). The answers are a, b, and e.

Step-by-step explanation:

Evaluating Double-Stranded DNA Relationships

When evaluating double-stranded samples of DNA, several key relationships based on complementary base pairing must hold true. Firstly, the number of adenine (A) bases must equal the number of thymine (T) bases, and the number of guanine (G) bases must equal the number of cytosine (C) bases.

This is due to the base pairing rules observed by Erwin Chargaff, also known as Chargaff's rules.

Consequently, option b. (C + G) = (A + T) represents the correct relationship. Options a. and e., which imply that the sum of purines (A + G) should equal the sum of pyrimidines (T + C), are also correct based on Chargaff's findings.

To sum up, the correct answers are:
a. (A + G) = (T + C)
b. (C + G) = (A + T)
e. a and c