AP BIOLOGY

Detailed explanation-1: -Answer-Antiparallel Explanation-Arrangements of the sides of the DNA molecules are antiparallel. If two biopolymers are aligned parallel to each other but in opposite direction, they are antiparallel to each other.

Detailed explanation-2: -DNA is composed of two strands of nucleotides held together by hydrogen bonding. The strands each run from 5’ to 3’ and run in antiparallel, or opposite, directions from one another.

Detailed explanation-3: -The double helix looks like a twisted ladder-the rungs of the ladder are composed of pairs of nitrogenous bases (base pairs), and the sides of the ladder are made up of alternating sugar molecules and phosphate groups. Molecules of DNA range in length from hundreds of thousands to millions of base pairs.

Detailed explanation-4: -Answer is C: One DNA strand runs from the 5’-to-3’ direction and the other DNA strand runs from the 3’-to-5’ direction.

Detailed explanation-5: -If the DNA strand was parallel, replication would not be possible. The nucleotides would not be complementary to each other and, as a result, would not pair in a genetic molecule. Therefore, the DNA being antiparallel is the only way replication and life could occur.