gene
unit of heredity. region of dna that can be transcribed into an rna molecule and results in a functional product
mrna
specifies amino acid sequence of a protein. "how to build proteins"
trna
translates mrna into amino acids
rrna
part of ribosomes
transcription
produces a transcript (rna copy) of a gene
translation
synthesis of a protein (polypeptide on ribosome) using rna
translation in prokaryotes
DNA-mRNA-Protein
translation in eukaryotes
DNA-pre mRNA-mRNA-Protein
promoter
sequence of dna that controls when and where transcription will begin
terminator
specifies the end of transcription
regulatory sequences
sites for binding of regulatory proteins. some enhance transcription, some inhibit transcription.
initiation transcription
recognition of promoter
elongation transcription
rna polymerase synthesises rna.
termination transcription
rna polymerase reaches terminator. causes both polymerase and new rna transcript to dissociate from dna
tails
stability
caps
ribosomal recognition
genetic code
specifies relationship between bases in mrna and amino acids in polypeptide.
reading frame
start codon defines reading frame of a mature mrna; read as a group of three bases called a triplet.
aug
start codon
uga, uaa, uag
stop codons
trna common feature
cloverleaf structure
ribosomes
where translation takes place
initiation translation prokaryote
mrna, first trna, and ribosomal subunits assemble
elongation translation prokaryote
synthesis from start to stop codons
termination translation prokaryote
complex disassembles at stop codon releasing polypeptide
initiation translation eukaryotes
5' cap recognized, small ribosome binds, started trna with start codon in P site
elongation translation eukaryotes
new trna enters A site. the growing a polypeptide chain in P moves to A
termination translation eukaryotes
stop codon enters A site and recognized by release factors, protein released and ribosome disassembled
mutation
heritable change in genetic material
silent
mutation that cause no change
missense
mutation that changes one amino acid in polypeptide
nonsense
mutation that changes a normal codon into a stop codon
frameshift
mutation that produces a whole different amino acid sequence
germ-line cell
sex cells
somatic cell
all other cells in the body
mutagen
chemical of physical agents that alter dna
cancer
uncontrolled cell division
carcinogen
agents that increase the likelihood of developing cancer
proto-oncogenes
genes that promote the cell cycle.
gene expression
process where gene is made into a functional product
constitutive genes
gene that is constantly expressed
regulatory transcription factors
bind to regulatory sequence. can inhibit or promote transcription
small effector molecules
bind to regulatory transcription factor and determines if it can bind to dna or not
TATA box
upstream from transcriptional start site
core promoter
TATA box and transcriptional start site
chromatin
complex created by dna and protein
atp dependent chromatin remodeling complexes
makes dna more or less amenable to transcription
aminoacyl-trna synthetase
Catalyzes attachment of amino acids to tRNA
P53
G1 checkpoint protein, tumor suppressor