ch 7 Flashcards
parts of mRNA
5’ UTR
start codon
open reading frame
stop codon
3’ UTR
open reading frame
holds instructions to make proteins
only part that gets translated
located in middle of mRNA
start codon
where translation starts
stop codon
where translation ends
5’ untranslated region UTR
not translated
front of mRNA
regulatory information, controls translation
3’ untranslated region UTR
not translated
back of mRNA
regulatory information, controls translation
3 main steps in translation
initiation
elongation
termination
translation is carried out by ____
ribosomes
what are the two main ribosome subunits
large and small subunit
translation: initiation
initiation factors coordinate its binding
small subunit binds to mRNA
finds start codon
recruits large ribosomal subunit
translation: elongation
ribosomes reads open frame and makes polypeptide
RNA nucleotides dictates amino acid sequence
tRNAs decode mRNAs message
T/F: three mRNA nucleotides = one codon
true
tRNA parts
anticodon
acceptor stem
anticodon
binds to codon based on complementary base pairing
acceptor stem
where amino acid is attached to tRNA
tRNA charging
amino acids is covalently attached to tRNA molecule
aminoacyl tRNA synthetases
catalyzes tRNA charging
20 different ones for each amino acids
translation: elongation
charged tRNA is brought to the ribosome
ribosome covalently attaches amino acid to polypeptide chain
ribosome translocates forward one codon and repeats
ribosomes have _____ regions where tRNAs bind
3
A site
P site
E site
Acceptor site
where charged tRNAs first enter
Peptide site
amino acids of tRNA is moved to growing polypeptide
peptide bond forms
Exit site
where used, uncharged tRNA leaves
translation: termination
reaches stop codon, translation ends
stop codons are bound by ______ instead of tRNA
release factor
release factor
protein that causes mRNA and ribosome to separate
translation repressors
proteins that bind mRNA and stop translation
sensitive to cellular conditions
chaperones
proteins that assist in folding other proteins into proper shape
three main types of chaperones
Hsp70 chaperones
Chaperonins
Protein disulfide isomerases
Hsp70
heat-shock protein 70
bind new polypeptides
transport them to other places in cell
chaperonins
large, barrel-shaped proteins that fold other proteins
repeatedly bind and release target protein
causes it to fold
requires energy
protein disulfide isomerases
enzymes that catalyze the bond between cysteine amino acids across a polypeptide
helps protein fold into proper shape
protein cleavage
pieces of proteins are cut off
helps them become active
proteases
enzymes involved in protein cleavage
zygomens / proproteins
proteins initially inactive by design
cleavage of repressive region activates the protein
example of a protein that is activated or inactivated upon binding of small molecules
G proteins
example of a hormone that regulates proteins
estrogen
example of a vitamin that regulates proteins
vitamin D
post-translational modification
amino acids of a protein are chemically modified after a protein is built
alters proteins function
kinases
enzymes that add phosphate groups to proteins
conformational change
proteins shape changes when modified
phosphatases
enzymes that remove phosphate groups
protein-protein interactions are based on
shape and electrical charge of proteins
mechanisms of protein regulation
small molecule regulators
post-translational modifications
protein-protein interactions
altered cellular location
protein degradation
ubiquitin
small protein attached to other proteins
takes the proteins to proteasome to be degraded into amino acids
ubiquitination
attachment of ubiquitins to proteins
proteasome
degrades proteins into amino acids
