AP BIOLOGY

Detailed explanation-1: -Complementary bases attach to one another (A-T and C-G). The primary enzyme involved in this is DNA polymerase which joins nucleotides to synthesize the new complementary strand. DNA polymerase also proofreads each new DNA strand to make sure that there are no errors.

Detailed explanation-2: -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-3: -Complementary base pairing is important in DNA as it allows the base pairs to be arranged in the most energetically favourable way; it is essential in forming the helical structure of DNA. It is also important in replication as it allows semiconservative replication.

Detailed explanation-4: -The upper strand of DNA is the “mRNA-like” strand. The lower strand is the strand that is complementary to the mRNA.