Components Of Translatiom

Question 1

List components of translation

Answer 1

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

Question 2

What happens if a aas is deleted

Answer 2

-translation stops at the codon for that aas

Question 3

Number of tRNA in pro and eukaryotes

Answer 3

30

-50 in eukaryotes

Question 4

Isoaccepting tRNA and where true

Answer 4

• numerous tRNA binding to the same aas

- true where aas are coded by more than one codon

Question 5

Amino acid attachment site where found and function and how it does its function

Answer 5

• 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

Question 6

Charged tRNA and activated aas description

Answer 6

• has an aas bound to its acceptor arm ( no aas means uncharged )
• attached to tRNA

Question 7

Describe anticodon and its function

Answer 7

• 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

Question 8

Aminoacyl-tRNA synthetases

Answer 8

• family of enzymes which attack aas to their tRNA’s

- each member recognizes a cognate aas and its tRNA

Question 9

Describe addition of aas to tRNA

Answer 9

• 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

Question 10

What shows high fidelity of synthetase

Answer 10

-can recognize cognate aas and its tRNA

Question 11

Proof/reading of sythetase

Answer 11

-can removed incorrectly attached aas to enzyme or tRNA

Question 12

Why aren’t Svedberg not additive

Answer 12

-they represent both size and shape of particle

Question 13

Function of subunits

Answer 13

-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

Question 14

Function of ribosomal proteins

Answer 14

• structural integrity of ribosome

- interactions with other components of synthesis machinery

Question 15

Describe A P And sites, function and where found

Answer 15

• 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

Question 16

Function of A site codon

Answer 16

-specifies which aas is to be added next

Question 17

Protein factors function and types

Answer 17

• required for protein synthesis
• perform catalytic function or stabilize synthesis machinery
• initiation
• elongation
• termination

Question 18

What type of proteins are protein factors and significance

Answer 18

• monomeric g-proteins

- active when bound to GTP and inactive to GDP

Question 19

Use of GTP and ATP in translation

Answer 19

-sources of energy

Question 20

How many energy bonds needed for 1 aas and where found

Answer 20

-4 bond are needed

1 : 2 from ATP aminoacyl-synthetase activity

• 1 cleaved when adding AMP to enzyme
• 1 when pyrophosphate is cleaved

2 : 2 from GTP

• 1 when tRNA is bound to mRNA
• 1 during translocation