Term | Definition |
bacteriophage | virus that infects bacteria |
nucleotides | the small units that make up DNA |
double helix | model in which two strands of DNA wind around each other like a twisted ladder |
base paring rules | rules as to how the bases of two DNA strands always pair up
- thymine always pairs with adenine
- cytosine always pairs with guanine |
replication | the process by which DNA is copied during the cell cycle |
DNA polymerase | the group of enzymes that bond the new nucleotides together |
central dogma | states that information in one direction, from DNA to RNA to proteins |
RNA | ribonucleic acid |
transcription | the process of copying a sequence of DNA to produce a complementary strand of RNA |
RNA polymerase | enzymes that bond nucleotides together in a chain to make a new RNA molecule |
messenger RNA | an intermediate message that is translated to form a protein |
ribosomal RNA | forms part of ribosomes, a cell's protein factories |
transfer RNA | brings amino acids from the cytoplasm to a ribosome to help make the growing protein |
translation | the process that converts an mRNA message into a polypeptide |
codon | a sequence of three nucleotides that codes for an amino acid |
stop codon | signal the end of the amino acid chain |
start codon | signals the start of translation and the amino acid methionine |
anticodon | a set of three nucleotides that is complementary to an mRNA codon |
promoter | a DNA segment that allows a gene to be transcribed |
operon | a region 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 |
exons | nucleotide segments that code for parts of the protein |
intron | nucleotide segments that intervene, or occur, between exons |
mutation | a change in an organism's DNA |
point mutation | a mutation in which one nucleotide is put in that place of the correct nucleotide |
frameshift mutation | the insertion or deletion of a nucleotide in the DNA sequence |
mutagen | an agent in the environment that can change DNA |