Gene Expression Review 3

Question 1

Peptide bond formation during translation is carried out by which subunit of the ribosome?

Answer 1

large

Question 2

Thiostrepton inhibits EF-G. What part of the prokaryotic translation does it likely influence?

Answer 2

Ribosomal translocation

Question 3

What is the major difference between prokaryotic and eukaryotic translation initiation?

Answer 3

Prokaryotic translation involves the joining of the mRNA and small ribosomal subunit before entry of the initiator tRNA. Eukaryotic translation involves joining of the initiator tRNA to the small subunit before mRNA joining.

Question 4

What is the sequence of eukaryotic mRNA?

Answer 4

GCCACC

Question 5

What kind of mutation results from and amino acid change?

Answer 5

missense

Question 6

What kind of mutation results from the loss of two nucleotides?

Answer 6

frameshift

Question 7

Which region in the figure above is bound by the poly (A) binding Protein (PABP)?

Answer 7

Region K (AAAAAAAAAA)

Question 8

Between which two regions will a mutation most likely alter the protein sequence?

Answer 8

E and F (AUGC—//—AGGU—)

Question 9

Which region in the figure is bound by elF4e?

Answer 9

Region J (7mG)

Question 10

A mutation to which region in the figure above would disrupt recognition by the 18S rRNA of the small ribosomal subunit?

Answer 10

Region D (—GCCACC)

Question 11

Which regions in the figure is most important for forming a closed-loop mRNA structure?

Answer 11

J and K (7mG and AAAAAAAA)

Question 12

Which eukaryotic translation factor is required for a closed-loop mRNA structure found in the cytosol?

Answer 12

elF-4G

Question 13

The genetic code is degenerate. Which of the following describes what they mean?

Answer 13

A given amino acid can be specified by more than one codon

Question 14

Translation releasing factors (RF-1, RF-2, and Rf-3) are GTP-dependent proteins that enter into the A-site of the ribosomes when it is unoccupied due to a STOP codon. They promote hydrolysis of what?

Answer 14

The ester bond linking the polypeptide with the peptidyl site tRNA in the P-site

Question 15

Which enzyme charges tRNA with the correct amino acid?

Answer 15

amino acyl tRNA synthetase

Question 16

Which factor determines where translation initiates?

Answer 16

18s rRNA

Question 17

Which factor recognizes UAA and UAG codons in mRNA?

Answer 17

RF-1

Question 18

In which region of gene X in mutant strain #1 might there be a mutation which accounts for the large mRNA transcript?

Answer 18

branch point adenosine

Question 19

Why is Protein X in mutant strain #1 smaller than Protein X in the wld type strain (despite having a larger mRNA)

Answer 19

The mutation of gene X n strain #1 results in fully processed transcript still containing an intron

Question 20

In which region of gene X in mutant strain #2 might there be a mutation which accounts for a temperature sensitive Protein X?

Answer 20

exon

Question 21

What type of mutation occurs in the gene encoding Protein X from mutant strain #2?

Answer 21

missense

Question 22

In what kind of phospholipids, saturated or unsaturated, do you expect the level to be increased in a plasma membrane of bacteria that was moved from 37’C to 4’C?

Answer 22

unsaturated

Question 23

What extracting agent would be used for extracting integral proteins from the membrane?

Answer 23

non-ionic detergent

Question 24

What extracting agent would be used for extracting peripheral proteins from the membrane?

Answer 24

salt solution

Question 25

What extracting agent would be used for extracting lipid-anchored proteins from the membrane?

Answer 25

phospholipase