Term | Definition |
bacteriophage | type of virus that stakes over a bacterium's genetic machinery and directs it to make more viruses |
nucleotides | the small units, or monomers, that make up DNA |
double helix | where two strands of DNA wind around each other like a twisted ladder |
base pairing rules | Thymine (T) pairs with adenine (A), ca cytosine (C) pairs with guanine (G) |
replication | the process by which DNA is copied during the cell cycle |
DNA polymerase | a group of enzymes that bond the new nucleotides together |
central dogma | states that information flows in one direction, from DNA to RNA to proteins |
RNA | a chain of nucleotides, each made of a sugar, a phosphate group, and a nitrogen-containing base |
transcription | the process of copying a sequence of DNA to produce a complementary strand of RNA |
RNA polymerases | enzymes that bond nucleotides together in a chain to make a new RNA molecule |
Messenger RNA (mRNA) | an intermediate message that is translated to form a protein |
Ribosomal RNA (rRNA) | forms part of ribosomes, a cell''s protein factories |
Transfer RNA (tRNA) | brings amino acids from the cytoplasm to a ribosome to help make the growing protein |
translation | the process that converts, or translates, an mRNA message into a polypeptide |
codon | a three-nucleotide sequence that codes for an amino acid |
stop codon | signals 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 |
exon | nucleotide segments that code for parts of the protein |
introns | nucleotide segments that intervene, or occur, between atoms |
mutation | a change in an organism's DNA |
point mutation | a mutation in which one nucleo tide is substituted for another |
frameshift mutation | involves the insertion or deletion of a nucleotide in the DNA sequence |
mutagen | agents in the environment that can change DNA |