AP BIOLOGY

Detailed explanation-1: -Hydrogen bond (H-bond) binds the nitrogen bases between the two strands of DNA. There are two H-bonds between A and T; three H-bonds between G and C.

Detailed explanation-2: -The nitrogenous bases may form hydrogen bonds according to complementary base pairing: Adenine always forms two hydrogen bonds with thymine / uracil. Guanine always forms three hydrogen bonds with cytosine.

Detailed explanation-3: -Nitrogenous bases in nucleic acids are held together by hydrogen bonds. Hydrogen bonds occur when hydrogen is covalently bonded to a much more electronegative element such as chlorine or nitrogen.

Detailed explanation-4: -Within a molecule of DNA, pairs of bases are chemically bonded together by hydrogen bonds. These bonds hold the two strands of the molecule together. Bases pair up with each other in a consistent way, and this process is called complementary base pairing, or Watson-Crick base pairing.

Detailed explanation-5: -Hydrogen bonding in DNA The complementary base pairs of guanine with cytosine and adenine with thymine connect to one another using hydrogen bonds. These hydrogen bonds between complementary nucleotides are what keeps the two strands of a DNA helix together.