27-12-2012, 06:08 PM
SEMINAR ON TRANSLATION IN EUKARYOTES
TRANSLATION IN EUKARYOTES.pptx (Size: 352.29 KB / Downloads: 24)
INTRODUCTION
Translation is the synthesis of a polypeptide chain from its m-RNA template.
Biosynthesis of a protein or a polypeptide in a living cell.
Occurrence: in cytoplasm and also occur in mitochondria $ chloroplast.
COMPONENTS OF THE TRANSLATION
RIBOSOME : -
Ribosomes are macro-molecule ribonucleoprotein complex.
These are the centers of factories for protein synthesis.
On the basis of levels of organism the Ribosome are of two types.
In Prokaryotes :- 70 s Type
In Eukaryotes :- 80 s Type
Ribosome has 2 subunits.
m-RNA (Messenger RNA):-
m-RNA is an intermediate between a gene and its polypeptide.
Specific information require for synthesis of given protein is present on m-RNA.
The DNA passes the genetic information in the form of codon to m-RNA to translate into a protein sequence.
t-RNA (Transfer RNA):-
t-RNA has anticodon that recognize codon (complementary bases) of m-RNA for protein synthesis.
It have 5 arm’s
Amino acid is covalently bound to t-RNA at the 3’ end.
Termination
Chain elongation continues untill a termination codon ( UAA , UAG , UGA) reaches the ribosome chain is then terminated and released from the ribosome
Initiation
Ribosomal dissociation :-
At low Mg++ conc. 8Os 6Os + 4Os
After dissociation initiation factor IF-1A and IF3 together binds to 4Os and prevents association with 6Os subunit.
Formation of 43s complex :-
Ternary complex ( Aminoacylated tRNA + IF2 + GTP) binds with 4Os subunit to form 43s initiation complex .
conclusion
Genes produce their phenotypic effects by specifying the amino acid sequence of specific proteins.
Morphologically protein is very important in every living organisms.
So that the translation process occur in three steps: Initiation , Elongation , termination .