Chapter 7: The Blueprint of Life, from DNA to Protein - Translation

Question 1

Name the three steps of translation

Answer 1

• initiation
• elongation
• termination

Question 2

What occurs in initiation of translation? (5)

Answer 2

1. a ribosome assembles on the mRNA
2. a tRNA carrying AA formylmethionine enters the P site
3. a TRNA carrying a second AA enters ribosome
   - specified by codon in the A site
4. ribosomes join AA by peptide bonds

Question 3

What occurs in elongation? (4)

Answer 3

1. ribosome moves a distance of one codon down the mRNA
2. the next codon is now placed in the A site
3. the correct tRNA enters the A site, bringing with it the next amino acid to be added
4. AA joined to the chain, forming a polypeptide

Question 4

When does elongation stop?

Answer 4

• When stop codon is reached

Question 5

What occurs in termination? (3)

Answer 5

1. When a stop codon enters the A site, the ribosome disassembles and releases the polypeptide
2. The polypeptide is folded into the correct shape and becomes a protein
3. The ribosome can initiate translation of another mRNA