Translation: mRNA to Protein

Question 1

3 Stages of Translation

Answer 1

1. Initiation
2. Elongation
3. Termination

Question 2

Initiation Simple Definition

Answer 2

mRNA joins a ribosome

Question 3

Elongation Simple Definition

Answer 3

Polypeptide grows

Question 4

Termination Simple Definition

Answer 4

Ribosome, tRNA, mRNA and polypeptide all dissociate

Question 5

Initiation - A

Answer 5

Small ribosomal subunit binds to mRNA

Question 6

Initiation - B

Answer 6

An initiator tRNA with anticodon UAC base-pairs makes H-bonds with AUG stat codon on an mRNA molecule

Question 7

Initiation - C

Answer 7

Initiator tRNA carries the amino acid called methionine (Met)

Question 8

Initiation - D

Answer 8

• Large ribosomal subunits binds
• Forms the initiation complex
• 3 sites are formed

Question 9

How is the initiation complex formed?

Answer 9

With the help of proteins called initiation factors

Question 10

A site

Answer 10

Aminoacyl-tRNA site

Question 11

P Site

Answer 11

• Peptidyl-tRNA site

Question 12

Where is initiator tRNA found?

Answer 12

In the P site

Question 13

E Site

Answer 13

Exit

Question 14

Note about initiation

Answer 14

GTP (energy) is required for initiation

Question 15

Steps of Elongation

Answer 15

• Codon recognition
• Peptide Bond Formation
• Translocation
• Repeat

Question 16

Codon Recognition

Answer 16

• mRNA codon in A site forms H-bonds with the anticodon of the incoming aminoacyl-tRNA
• elongation factor then ushers tRNA in

Question 17

Peptide Bond Formation

Answer 17

Ribosome catalyzes the formation of peptide bonds between the amino acid in P site with the amino acid in A site

Question 18

Translocation

Answer 18

• tRNA in A site is moved to P site taking mRNA with it
• The tRNA in the P site moves to the E site and is released
• Ribosome shifts position by 1 codon

Question 19

What does the process of translocation require?

Answer 19

The hydrolysis of GTP

Question 20

Repeat

Answer 20

• Repeat process until polypeptide is complete

Question 21

Definition of the word Translocation

Answer 21

Process of shifting

Question 22

Termination - A

Answer 22

Ribosome reaches termination codon (STOP codon) on mRNA

Question 23

Termination - B

Answer 23

A site accepts a protein called a release factor instead of tRNA

Question 24

Termination - C

Answer 24

• Release factor hydrolyzes the bond between tRNA and amino acid in P site
• Polypeptide is freed

Question 25

What does hydrolyzes mean?

Answer 25

Add water instead of an amino acid to polypeptide chain

Question 26

Termination - D

Answer 26

Ribosomal subunits dissociates

Question 27

What are polyribosomes?

Answer 27

• More than 1 ribosome can attach and synthesis many polypeptides at the same time
• Forms a string of ribosomes

Question 28

What do polyribosomes help with?

Answer 28

Help create many copies of a protein if speedy synthesis is needed

Question 29

Aminoacyl tRNA=

Answer 29

tRNA + Amino Acid