Question

question 7 of 10
which statement is true of base pairing in dna?
a. one strand has only guanine and cytosine, and the other strand has only adenine and thymine.

b. guanine in one strand pairs with cytosine in the other strand.

c. one strand has only adenine and guanine, and other strand has only cytosine and thymine.

d. cytosine in one strand pairs with cytosine in the other strand.

Explanation:

To determine the true statement about DNA base pairing, we recall the base - pairing rules in DNA: adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).

• Option A: DNA strands contain all four bases (A, T, G, C), not that one strand has only G and C and the other only A and T. So this is incorrect.
• Option B: According to the base - pairing rule, guanine (G) in one strand pairs with cytosine (C) in the complementary strand. This is consistent with the known base - pairing in DNA.
• Option C: DNA strands have all four bases, not that one strand has only A and G and the other only C and T. So this is incorrect.
• Option D: Cytosine (C) should pair with guanine (G), not with another cytosine (C). So this is incorrect.

Answer:

B. Guanine in one strand pairs with cytosine in the other strand.