Components Of Translatiom Flashcards
List components of translation
1 amino acids for the peptide 2 amino-acyl tRNA 3 mRNA template 4 protein factors 5 A,P and E binding sites on ribosome 6 functioning competent ribosomes -rRNA and ribosomal proteins
What happens if a aas is deleted
-translation stops at the codon for that aas
Number of tRNA in pro and eukaryotes
30
-50 in eukaryotes
Isoaccepting tRNA and where true
- numerous tRNA binding to the same aas
- true where aas are coded by more than one codon
Amino acid attachment site where found and function and how it does its function
- found on acceptor arm of tRNA at 3’ OH end of CCA
- binds to a cognate aas via an ester linkage between 3’-OH end and carboxyl of aas
Charged tRNA and activated aas description
- has an aas bound to its acceptor arm ( no aas means uncharged )
- attached to tRNA
Describe anticodon and its function
- found on tRNA
- 3 base sequence on tRNA that pairs with specific codon on mRNA
- specifies insertion of aas carried by tRNA to growing peptide
Aminoacyl-tRNA synthetases
- family of enzymes which attack aas to their tRNA’s
- each member recognizes a cognate aas and its tRNA
Describe addition of aas to tRNA
- aminoacyl-synthetase ( E )cleaves ATP into AMP and PPi
- E binds to AMP and aas
- AMP cleaved from enzyme and energy used to form ester bond between aas and tRNA
- enzyme released
What shows high fidelity of synthetase
-can recognize cognate aas and its tRNA
Proof/reading of sythetase
-can removed incorrectly attached aas to enzyme or tRNA
Why aren’t Svedberg not additive
-they represent both size and shape of particle
Function of subunits
-small : binds to mRNA , ensures accuracy of translation by ensuring correct tRNA anti codon and mRNA codon pairing
Large : catalyses formation of peptide bonds that link residues
Function of ribosomal proteins
- structural integrity of ribosome
- interactions with other components of synthesis machinery
Describe A P And sites, function and where found
- binding sites of tRNA on ribosome
- they cover 3 neighboring codons
- A binds to incoming aminoacyl-tRNA
- P binds to peptidyl-tRNA : carries already added aas
- E occupied by empty tRNA about to leave ribosome