Question

a strand of dna contains the bases adenine, cytosine, cytosine, and guanine, in that order. which would be the order of the bases on the opposite strand of dna?
option 1: cytosine, adenine, adenine, and thymine
option 3: thymine, guanine, guanine, and cytosine

Explanation:

Step1: Recall DNA base pairing

In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).

Step2: Pair each base

Original strand bases: adenine (A), cytosine (C), cytosine (C), guanine (G).

• A pairs with T.
• C pairs with G.
• C pairs with G.
• G pairs with C.

So the opposite strand bases should be thymine (T), guanine (G), guanine (G), cytosine (C).

Step3: Match with options

Check the options. The third option is "thymine, guanine, guanine, and cytosine", which matches the paired bases.

Answer:

thymine, guanine, guanine, and cytosine (the third option)