Chapter 14.6.2 (Exam 3) tRNA

Question 1

How are tRNAs charged?

Answer 1

By an enzyme – aminoacyl-tRNA synthetases; requires ATP

Each enzyme is specific for one amino acid and its corresponding tRNA

Question 2

Where does translation occur?

Answer 2

Ribosome in the cytoplasm

Question 3

Describe how ribosomes help translation occur.

Answer 3

It holds mRNA and charged tRNAs in the correct position to allow polypeptide assembly

2 subunits
Non-covalently attached
Made of rRNA and proteins

Question 4

What are the three binding sites on the large subunit of a ribosome?

Answer 4

A (aminoacyl tRNA) site

P (peptidyl tRNA) site

E (exit) site

Question 5

Describe the A (aminoacyl tRNA) site of a ribosome.

Answer 5

Binds with the anticodon of charged tRNA

Question 6

Describe the P (peptidyl tRNA) site of a ribosome.

Answer 6

Where tRNA with the growing peptide chain sits

Question 7

Describe the E (exit) site site of a ribosome.

Answer 7

Where tRNA sits before being released from the ribosome

Question 8

Describe the three steps of translation.

Answer 8

Initiation – formation of initiation complex

Elongation – formation of the polypeptide chain by addition of amino acids

Termination – translation stops after reaching a stop codon