Tools A B nitrogen base organic ring stucture that contains one or more atoms of nitrogen double helix DNA is composed of 2 twisted strands replication Every time a cell reproduces by mitosis or a gamete is formed by meiosis, DNA is copied codon each set of 3 nitrogen bases representing an amino acid transcription enzymes make an RNA copy of a DNA strand mRNA RNA copy that carries info from DNA out into the cytoplasm rRNA portions of the of DNA code for the RNA that makes up ribosomes translation the process of converting the info in a sequence of amino aces that make up protein tRNA brings amino acids to the ribosomes so they can be assembled into proteins mutation any mistake or change in the DNA sequence point mutation change in a single base pair in DNA frameshift mutation mutation in which a single base is added or deleted from DNA nondisjunction the failure of homologous chromosomes to seperate properly during meiosis trisomy when a gamete w/ an extra chromosome is fertilized by a normal gamete, they zygote will have an extra chromosome