Genetics & Molecular Biology

A double helix of two antiparallel nucleotide strands; each nucleotide has a deoxyribose sugar, a phosphate, and a nitrogenous base. The backbone is sugar-phosphate.

Adenine pairs with thymine (A-T) by two hydrogen bonds; guanine pairs with cytosine (G-C) by three hydrogen bonds.

Each nucleotide consists of a five-carbon sugar, a phosphate group, and a nitrogenous base (purine: A or G; pyrimidine: C, T, or U).

Each new DNA molecule retains one original (parental) strand and one newly synthesized strand, so the original information is conserved.

The enzyme that synthesizes new DNA by adding nucleotides to the 3' end of a growing strand, using the template strand to direct base pairing.

The leading strand is synthesized continuously toward the replication fork; the lagging strand is made discontinuously in Okazaki fragments away from the fork.