DNA translation

define the translation

process of synthesise proteins in cytoplasm using mRNA as a template

what is the genetic codon made from

how many codons DNA have

type of them

why initiation codon is a sense codon

what are non sense codons

3 adjunct nucleotides

64

61 sense codons 3 non sens codons

because it code fro an aa methionine (AUG)3

UAA UGA UAG

مش عارف بس خايف يجيب حاجة عليها

tuna anticodon are complimenrty for mRNA codons مبهر جدا

what are characters of genetic codon

linear

triplet

specific

universal

degenerate

non overlapping and comma less

explain linear

mRNA codon bases are read from 5>3 end

compare between triplet and specific

triplet codon on mRNA specify certain aa

each codon code for specific aa

explain universal and degenerate

they are the sam in all species

certain aa has more than one codon

what is the defence between codons who code for the same aa

the 3rd base

what is the requirements of translation

ribosome

mRNA

tRNA

aa

aminoacteyl synthesise

protein factors

source of energy

what does the mRNA does

carries the information of arranging the aa in proper order of specific protein

name the steps fro translation and what’s their main event

1 activation of aa: synthesis of aminoactyl tRNA

2 initiation : formation of initiation complex

3elongation: synthesis of polypeptide chain

4termination : release of poly peptide chain

what happens in activation of aa

charging tRNA with its specific aa. on 3 oh end on acceptor arm

how charging OF tRNA done

by amino acetyl tRNA snythetase

does require energy

yes 2 high energy bonds from one ATP molecule

what are the transition machinery made of

ribosome mRNA

initiator tRNA that carries the first amino acid ( you know who it is)

initiation factor

first amino acid is methionine bth

what is the elongation step is catalysed by

is it acyclic process

elongation factors

yes it is

what are the steps

1 binding of new aminactyl tRNA to a site 1 GTP + ef

2 formation of peptide bond between newly and old amino acid catalysed by peptide transferase

3 translocation: ribosome move 1 codon toward 3 end of mRNA using elongation factor 2 and 1 GTP

how many high energy phosphate bonds is needed for one peptide chain

4

2 from 1 ATP molecule

1gtp for adding amino acetyl tRNA

1 GTP for trans location

what happens after translocation

release of uncgcharged tRNA from e site

the peptide trna move from a to p site

A site become free and can be occupied by new aminoacyl tRNA

when does translation ends

when an termination codon is recognise in A site by releasing factors

what does rfs + piptdyl trnasfese+ GTP does

1 hydrolysis of the bond between polypeptide chain and tRNA

2 release both of tRNA and protein

3 dissociation of 80s ribosome into 60 s and 40s subunits

2and 3 results of 1

note the newly synthesised polypeptide chain is objected to post translation modification

name 3 inhibitors of translation

streptomycin : interfere with the initiation step

tetracycline: block A site preventing aminoacy trna from binding

erthromyocin: inhibits trans location step