Translation

Question 1

Where are the proteins synthesised?

Answer 1

In cytoplasm on ribosomes

Question 2

How are amino acids join together?

Answer 2

Via condensation reactions which joins the COOH to NH2

Question 3

What order is the series of residues in the proteins?

Answer 3

Nitrogen to Carboxl

Question 4

What direction does RNA read in?

Answer 4

5 prime to 3 prime

Question 5

How many tRNA sites are on a ribosome abs what are they?

Answer 5

3 sites

E P A SITE

Question 6

What is the role of the ribosomes?

Answer 6

Reads mRNA and translates it to an amino acid sequence and assembled the amino acids into a linear polymer

Question 7

Name 3 types or RNA and their roles

Answer 7

mRNA codes for proteins
rRNA
tRNA- adapter molecules carries amino acids in activated forms to the ribosome for protein synthesis

Question 8

What did Brenner and Crick discover in relation to the codons?

Answer 8

Codons contain 3 bases and non overlapping reading frame.

Question 9

How many tRNA bind to a ribosome at one time?

Answer 9

2 bind at a time

Question 10

Name the 3 sites on a ribosome and their roles

Answer 10

P (Peptidly) site - other tRNA
A (aminoacyl) site - where initiator tRNA binds carrying amino acid
E(exit) site

Question 11

Describe the DNA sequence/ how it is read.

Answer 11

Triplet Code
Degenerate
Non-overlapping
No punctuation

Question 12

What is the 3 letter code of the initiation codon and what does it code for?

Answer 12

AUG (also known as fMet)

Methionine

Question 13

Describe base pair wobbling

Answer 13

There are more possible codons than tRNAs hence the codons dont have perfect base pairing

Question 14

There are how many codons?

And how many tRNAs?

Answer 14

64 possible codons and 45 tRNA

Question 15

Name the 4 types of base pairing involved in base pairing

Answer 15

Cognate- perfect base pairing and wobble in 3rd base
Near cognate- wobble in first base
Non-cognate - no base pairing

Question 16

What is the importance of inosine?

Answer 16

Inosines on tRNA gives greater wobble in 3rd position

Question 17

Which nucleotide of the anticodon loop needs to be ‘good enough’ for translation?

Answer 17

3rd nucleotide

Question 18

State the equation that shows how amino acids are activated

Answer 18

ATP + amino acid -> Aminoacyl adenylate + PPi

Question 19

State the equation for the formation of Aminoacyl-tRNA

Answer 19

Aminoacyl adenylate +tRNA –> Aminoacyl-tRNA + AMP

Question 20

Describe elongation

Answer 20

fMet addition
2nd tRNA in A-site
Peptidyl reaction ( 23S rRNA)
rachet from P-site to E-site
3rd tRNA in A site

Question 21

Name the 3 stages of translation

Answer 21

Initiation
Elongation
Termination

Question 22

How is the relationship between transcription and translation differ in bacteria and eukaryotes?

Answer 22

Transcription and translation are coupled in bacteria but not in Euk.

Question 23

Name the 3 stop codons

Answer 23

UAA
UAG
UGA

Question 24

Describe termination

Answer 24

Stop codon is read and release factor is recruited to A-site and chain is released

Question 25

Name the 4 examples of errors in the coding

Answer 25

Missense (same charge)
Silent (diff. protein same aa
nonsense (stop codon)
Frameshift/base deletion

Question 26

Which types of ribosomes do antibiotics work on

Answer 26

70S not 80S