02.14 - Translation

Question 1

Which of the following is not needed in translation?

a. Promoter sequence
b. Translation factors
c. Energy sources
d. Enzymes

Answer 1

a. Promoter sequence

Question 2

In which part of the tRNA is the amino acid attached?

Answer 2

Acceptor arm/3’ end

Question 3

Which part of the tRNA contains the recognition site for specific aminoacyl-tRNA synthetase?

Answer 3

D arm

Question 4

Which part of the tRNA binds aminoacyl-tRNA to ribosomal subunit?

Answer 4

Thymidine-Pseudouridine-Cystidine Arm

Question 5

True or False: The binding of specific amino acids with their corresponding tRNAs requires ATP.

Answer 5

True

Question 6

Which part of the amino acid binds to the 3’ end of the tRNA?

Answer 6

Carboxyl end

Question 7

This process involves the conversion of RNA into a protein product.

Answer 7

Translation

Question 8

When multiple codons can code for the same amino acid, translation is said to be __________.

Answer 8

Degenerate

Question 9

When a particular codon can code only for a single amino acid, it is said to be ___________.

Answer 9

Unambiguous

Question 10

Which of the following is not a characteristic of the genetic code in translation?

a. Overlapping
b. Unpunctuated
c. Universal
d. None of the above

Answer 10

a. Overlapping (There is no overlap in reading codons.)

Question 11

Which is the first step in the initiation phase of translation?

Answer 11

Dissociation of ribosomes into 40S and 60S subunits

Question 12

Which initiation factors stabilises the dissociated ribosomal subunits?

Answer 12

eIF-3 and eIF-1A

Question 13

What initiation factor binds to GTP to form a complex that binds to methionyl-tRNA?

Answer 13

eIF-2

Question 14

The eIF-2-GTP-Met-tRNA complex binds to which ribosomal subunit to form the 43S pre initiation complex?

Answer 14

40S subunit

Question 15

What forms when mRNA binds to the 43S pre-initiation complex?

Answer 15

48S initiation complex

Question 16

What initiation factor complex is responsible for the binding and removal of the mRNA 5’ methyl cap?

Answer 16

eIF-4F complex

Question 17

What specific initiation factor serves as a scaffolding protein that holds other initiation factors of the eIF-4F complex?

Answer 17

eIF-4G

Question 18

Which initiation factor is responsible for recognising and binding to the methyl cap?

Answer 18

eIF-4E

Question 19

What inhibits initiation when bound to eIF-4E?

Answer 19

BP-1

Question 20

What triggers the detachment of BP-1 from eIF-4E?

Answer 20

Phosphorylation by insulin and mitogens

Question 21

What initiation factors removes the 5’ methyl cap from the rest of the mRNA?

Answer 21

eIF-4A and eIF-4B

Question 22

What is the prokaryotic counterpart of the eukaryotic 5’ cap?

Answer 22

Shine-Dalgarno sequence

Question 23

This consensus sequence covers purines from -3 to +4 around the AUG sequence, and is scanned by the 48S initiation complex.

Answer 23

Kozak sequence

Question 24

Binding of the 48S initiation complex into the 60S subunit forms _____________.

Answer 24

80S initiation complex

Question 25

Which initiation factor hydrolyses the GTP bound to eIF-2 to remove all initiation factors from the complex?

Answer 25

eIF-5

Question 26

Which is not part of the 80S initiation complex a. 40S and 60S subunits b. mRNA without methyl cap c. Initiation factors d. Met-tRNA

Answer 26

c. Initiation factors

Question 27

What phase follows the initiation phase of translation?

Answer 27

Elongation

Question 28

What elongation factor binds to GTP, forming a complex that bdins with the entering aminoacyl-tRNA?

Answer 28

eEF-1alpha

Question 29

Which of the following statements is incorrect? a. The amino group of A site aminoacyl-tRNA will make a nucleophilic attack on the carbonyl group of the P site aminoacyl tRNA. b. Peptide bond formation is catalysed by peptidyltransferase. c. Peptidyltransferase is a component of the 40S subunit. d. None of the above.

Answer 29

c. Peptidyltransferase is a component of the 40S subunit. (It is a component of the 60S subunit.)

Question 30

What elongation complex facilitates the transfer of A-site tRNA to the P site?

Answer 30

eEF-2 + GTP

Question 31

How many ATPs are consumed in the activation of tRNA?

Answer 31

2 ATPs

Question 32

How many GTPs are consumed in the entry of aminoacyl-tRNA into the A site?

Answer 32

1 GTP

Question 33

How many GTPs are consumed in the translocation of mRNA along the ribosome?

Answer 33

1 GTP

Question 34

How many ATPs and GTPs are consumed in the initiation phase?

Answer 34

``` 1 ATP (ATP hydrolysis facilitates mRNA binding to 43S complex) 1 GTP (GTP binds to eIF-2, which is then hydrolysed by eIF-5 for the release of initiation factors) ```

Question 35

A hypothetical polypeptide chain is composed of Met-Val. How many ATPs and GTPs are consumed in the overall translation process?

Answer 35

1 ATP + 1 GTP (initiation) 2 ATP + 1 GTP + 1 GTP (elongation) 1 GTP (termination) = 3 ATPs and 4 GTPs

Question 36

What removes the polypeptide chain from the P-site tRNA?

Answer 36

eRFs + GTP + peptidyltransferase

Question 37

What reaction is facilitated by the eRF-GTP-peptidyltransferase complex?

Answer 37

Hydrolysis

Question 38

What release factor responds to UAA and UAG stop codons?

Answer 38

eRF-1

Question 39

What release factor responds to UAA and UGA stop codons?

Answer 39

eRF-2

Question 40

What release factor binds to GTP?

Answer 40

eRF-3