3. Control of Gene Expression - Translation of mRNA into a Polypeptide

Question 1

What is a codon?

Answer 1

A sequence of three bases on an mRNA molecule

Question 2

What is an anticodon?

Answer 2

A sequence of three bases on a tRNA molecule

Question 3

Each tRNA molecule can only…

Answer 3

carry its specific amino acid

Question 4

What is the triplet code?

Answer 4

The sequence of codons determines the order in which tRNA molecules will enter the ribosome (as only complementary anticodon can bind with each codon), and this determines the sequence tat the amino acids will be peptide bonded together in the newly forming polypeptide. Pairing of RNA A:U G:C.

Question 5

1. What does the start codon allow?

Answer 5

The mRNA to enter the ribosome to start the formation of a new polypeptide

Question 6

2. What is codon recognition?

Answer 6

When the ribosome matches the anticodon of an incoming tRNA to the next codon on the mRNA

Question 7

3. What is peptide bond formation?

Answer 7

When the ribosome catalyses the peptide bond between amino acids - it adds the growing polypeptide chain onto the amino acid of the newly arrived tRNA

Question 8

4. What happens during the exit of tRNA?

Answer 8

The tRNA that was previously connected to the polypeptide chain now leaves the ribosome

Question 9

5. What do stop codons allow for?

Answer 9

the polypeptide to be detached and released