Gene regulation and protein synthesis Flashcards
central dogma
dna transcribed to rna (nucleotide to nucleotide) and translated to a protein (nucleotide to amino acid)
what happens during translation
anticodons of tRNA form base pairs with codons on mRNA
how many nucleotides to codons and anticodons consist of
3
degenerate
many amino acids have more than one codon
unambigious
each codon only codes for one amino acid
role of aminoacyl trna synthetases
bind amino acids to their corresponding trna molecules
bond between trna and mrna
covalent given from atp
how many rrna molecules do ribosomes contain
4
how many trna binding sites do ribosomes have
3; exit, peptidyl, aminoacyl
what happens to GDP for initiation
is hydrolysed to provide energy
steps of initiation
small ribosomal subunit binds to 5 end of mrna
moves along mrna until AUG (start codon) is found
special initiator trna with UAC anticodon pairs
steps of elomgation
An elongation factor (EF-1a), brings the next aminoacyl-tRNA to the A site
anticodon base-pairs with codon
GTP is hydrolysed, EF is released from tRNA
A second elongation factor (EFbg) regenerates EF1a to pick up the next aminoacyl-tRNA
role of peptidly transferase
catalyses peptide bond formation between amino acids in the P and A sites
termination
occurs when a site of ribosome encounters a stop codon
where do free ribosomes make proteins destined for
cytosol
nucleus
mitochondria
how are proteins from free ribosomes translocated
post translationally
bound ribosomes destination
plasma membrane
er
golgi
secretion
how are bound ribosome proteins translocated
co translationally
post translational modifications
proteolysis
glyosylation
phosphorylation
glycosylation
adding sugars
proteolysis
breakdwon of proteins into smaller polyppetides
function of kinases
catalyse phosphorylation
order of cenrtal dogma processes
transcription, splicing, translation, post trans;ational modification
what enzyme catalyses dna replicagition
dna polymerase
dna ligase
joins okazaki fragment s
helicase role
unwinds dna
primase
synthesises an rna primer
dna polymerase role
catalyses the replication of DNA
