| A | B |
|---|
| transformation | the process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria |
| bacteriophage | a virus that infects bacteria |
| nucleotide | a monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base |
| base pairing | a principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine |
| chromatin | the granular material visible within the nucleus; consists of DNA tightly coiled around proteins |
| histone | the globular protein molecule around which DNA is tightly coiled in chromatin |
| replication | the copying process by which a cell duplicates its DNA |
| DNA polymerase | the enzyme that "proofreads" new DNA strands, helping to ensure that each molecule is a nearly perfect copy of the original DNA |
| messenger RNA | mRNA, a RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell |
| ribosomal RNA | rRNA, a type of RNA that makes up the major part of ribosomes |
| transfer RNA | tRNA, a type of RNA molecule that transfers amino acids to ribosomes during protein synthesis |
| transcription | the process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in RNA |
| RNA polymerase | an enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription |
| promoter | the region of DNA that indicates to an enzyme where to bind to make RNA |
| intron | an intervening sequence of DNA; does not code for a protein |
| exon | the expressed sequence of DNA; codes for a protein |
| codon | a three-nucleotide sequence on messenger RNA that codes for a single amino acid |
| translation | the decoding of a mRNA message into a polypeptide chain |
| anticodon | a group of three bases on a tRNA molecule that are complementary to an mRNA codon |
| mutation | the change in DNA sequence that affects genetic information |
| point mutation | mutation that affects a single nucleotide, usually by substitutin one nucleotide for another |
| frameshift mutation | a mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide |
| operon | a group of genes operating together |
| operator | a region of chromosome in an operon to which the repressor binds when the operon is "turned off" |
| hox gene | a series of genes that controls the organs and tissues that develop in various parts of an embryo |
