Question

The number of H bonds between guanine and cytosine are

• A. One
• B. Two
• C. Three
• D. Four

Answer 1

The correct option is C Three

The number of H-bonds between guanine and cytosine are three. In a DNA double helix, each type of nucleobase on one strand bonds with just one type of nucleobase on the other strand. This is called complementary base pairing. Here, purines form hydrogen bonds to pyrimidines, with adenine bonding only to thymine in two hydrogen bonds, and cytosine bonding only to the guanine in three hydrogen bonds. This arrangement of two nucleotides binding together across the double helix is called a base pair. As hydrogen bonds are not covalent, they can be broken and rejoined relatively easily.

So, the correct answer is option C.