| A | B |
| DNA | molecule that stores genetic information in all organisms (stands for deoxyribonucleic acid) |
| bacteriophage | virus that infects bacteria |
| nucleotide | monomer that forms DNA and has a phosphate group, a sugar, and a nitrogen-containing base |
| double helix | model that compares the structure of a DNA molecule, in which two strands wind around one another, to that of a twisted ladder |
| base pairing rules | rule that describes how nucleotides form bonds in DNA; adenine (A) always bonds with thymine (T), and guanine (G) always bonds with cytosine (C) |
| replication | process by which DNA is copied |
| DNA polymerase | enzyme that makes bonds between nucleotides, forming an identical strand of DNA during replication |
| central dogma | theory that states that, in cells, information only flows from DNA to RNA to proteins |
| RNA | nucleic acid molecule that allows for the transmission of genetic information and protein synthesis |
| transcription | process of copying a nucleotide sequence of DNA to form a complementary strand of mRNA |
| RNA polymerase | enzyme that catalyzes the synthesis of a complementary strand of RNA from a DNA template |
| messenger RNA (mRNA) | form of RNA that carries genetic information from the nucleus (or nucleoid region) to the cytoplasm, where it serves as a template for protein synthesis |
| ribosomal RNA (rRNA) | RNA that is in the ribosome and guides the translation of mRNA into a protein; also used as a molecular clock |
| transfer RNA (tRNA) | form of RNA that brings amino acids to ribosomes during protein synthesis |
| translation | process by which mRNA is decoded and a protein is produced |
| codon | sequence of three nucleotides that codes for one amino acid |
| stop codon | codon that signals to ribosomes to stop translation |
| start codon | codon that signals to ribosomes to begin translation; codes for the first amino acid in a protein (methionine) |
| anticodon | set of three nucleotides in a tRNA molecule that binds to a complementary mRNA codon during translation |
| promoter | section of DNA to which RNA polymerase binds, starting the transcription of mRNA |
| operon | a section of DNA that includes a promoter, an operator, and one or more structural genes that code for all the proteins needed to do a specific task |
| exon | sequence of DNA that codes information for protein synthesis |
| intron | segment of a gene that does not codes information for protein synthesis |
| mutation | change in the DNA sequence |
| point mutation | mutation that involves a substitution of only one nucleotide |
| frameshift mutation | mutation that involves the insertion or deletion of a nucleotide in the DNA sequence |
| mutagen | agent that can induce or increase the frequency of mutation in organisms |