| Term | Definition |
| double helix | a twisted ladder shape formed by two strands of nucleotides twisted around eachother |
| nucleosome | repeating subunit of chromatin fibers consisting of DNA coiled around histones |
| semiconservative replication | method of DNA replication in which parental strands separate, act as templates, and produce molecules of DNA with one parental DNA strand and one new DNA strand |
| DNA polymerase | enzyme that catalyzes synthesis of new DNA fragments together |
| Okazaki fragment | short segment of DNA synthesized discontinuously in small segments in the 3' to 5' direction by DNA polymerase |
| RNA | ribonucleic acid; guides protein synthesis |
| messenger RNA | type of RNA that carries genetic information from DNA in the nucleus to direct protein synthesis in the cytoplasm |
| ribosomal RNA | type of RNA that associates with proteins to form ribosomes |
| transfer RNA | type of RNA that transports amino acids to the ribosome |
| transcription | process in which mRNA is synthesized from the template DNA |
| RNA polymerase | enzyme that regulates RNA synthesis |
| codon | three base code in DNA and RNA |
| intron | in RNA processing, the intervening coding sequence missing from the final mRNA |
| exon | in RNA processing, the codon sequence that remains in the final mRNA |