Deck 17: The Mechanism of Translation I: Initiation

Question 1

tRNA charging is the addition of a(n)___________ to the 3'end of a tRNA molecule.

Answer 1

amino acid

Question 2

Picornavirus mRNAs are not capped,yet they can still out compete host mRNAs for binding to the ribosome by

A)inactivating host Cap binding protein,eIF4F.
B)degrading host mRNA.
C)having a stronger affinity for the ribosome.
D)inactivation of host RNases.
E)inactivation of host Cap binding protein,eIF2B.

Answer 2

A

Question 3

Which of the following molecules does not interact with eIF4G?

A)Cap
B)alternative protein(x)
C)Pab1p
D)eIF3
E)eIF2

Answer 3

E

Question 4

There are _________ aminoacyl-tRNA synthetases,one for each amino acid.

Question 5

Match the following eukaryotic translation initiation factors with their correct function.
A.eIF2
B.eIF1
C.eIF3
D.eIF4F
E.eIF6
Bloom's Level: 1.Remember
Section: 17.02
This initiation factor is a Cap binding protein.D

Question 6

Match the following eukaryotic translation initiation factors with their correct function.
A.eIF2
B.eIF1
C.eIF3
D.eIF4F
E.eIF6
Bloom's Level: 1.Remember
Section: 17.02
This initiation factor binds to the 60S subunit and inhibits reassociation of the 40S and 60S subunits.E

Question 7

Match the following eukaryotic translation initiation factors with their correct function.
A.eIF2
B.eIF1
C.eIF3
D.eIF4F
E.eIF6
Bloom's Level: 1.Remember
Section: 17.02
This initiation factor aids in ribosome scanning to locate the initiation codon.B

Question 8

Which of the following is the best definition of translation?

A)a process by which pre-mRNA is transformed into mature mRNA
B)the process by which pre-mRNA is translated by ribozymes to produce proteins
C)a process by which a gene is converted into mRNA
D)the process by which ribosomes read the genetic message to produce a protein
E)a process by which a gene is converted into a protein

Question 9

Match the following eukaryotic translation initiation factors with their correct function.
A.eIF2
B.eIF1
C.eIF3
D.eIF4F
E.eIF6
Bloom's Level: 1.Remember
Section: 17.02
This initiation factor binds to the 40S subunit and inhibits reassociation of the 40S and 60S subunits.C

Question 10

_________________ studies have shown that eIF3 is a five-lobed protein that binds to eIF4G and to viral IRES.

Question 11

The Shine-Dalgarno sequence can be found in

A)mRNA.
B)tRNA.
C)5S rRNA.
D)16S rRNA.
E)30S ribosome.

Question 12

In prokaryotes the first amino acid incorporated into a polypeptide is a __________.

Question 13

Which of the following eukaryotic transcription factors is homologous to the prokaryotic transcription factor IF2?

A)eIF1A
B)eIF2B
C)eIF3
D)eIF4G
E)eIF5B

Question 14

Put the following steps of prokaryotic translation initiation in the correct order.(1)Binding of IF1,IF2,and GTP to the 30S subunit.(2)Binding of IF3 to the 30S subunit.(3)Binding of the 50S subunit and loss of IF1 and IF3.(4)Dissociation of the 70S ribosome.(5)Formation of the 70S initiation complex by dissociation of IF2 and GTP hydrolysis.(6)Formation of the 30S initiation complex.

A)4,2,1,6,3,5
B)2,1,6,3,5,4
C)5,6,3,2,1,4
D)1,2,3,4,5,6
E)2,4,1,6,3,5

Question 15

The _______ subunit of the E.coli ribosome binds the mRNA and tRNA while the _________ subunit has the peptidyl transferase activity.

Question 16

Which of the following initiation factors prevents reassociation of the 70S ribosome by binding to the free 30S subunit?

A)IF1
B)IF2
C)IF3
D)IF4
E)IF5

Question 17

Match the following eukaryotic translation initiation factors with their correct function.
A.eIF2
B.eIF1
C.eIF3
D.eIF4F
E.eIF6
Bloom's Level: 1.Remember
Section: 17.02
This initiation factor is involved in binding tRNA to the ribosome.A

Question 18

Which of the following is not part of the 30S initiation complex?

A)IF1,IF2,and IF3
B)5S rRNA
C)16S rRNA
D)amino-acyl tRNA
E)mRNA

Question 19

A(n)_______________ is defined as the area between an initiation codon and a downstream termination codon located in the same reading frame.

Question 20

Translation takes place in the _________________ of prokaryotes and in the _____________ of eukaryotes.

Question 21

In prokaryotes the first amino acid in all mature proteins is an N-formyl-methionine.

Question 22

Regions within mRNA that can bind small molecules to change conformation and thereby change gene expression are called_____________.

Question 23

Similar to prokaryotes,eukaryotic translation incorporates an N-formyl-methionine as the first amino acid.

Question 24

Very stable mRNA ______________ between the Cap and the initiation site can block ribosomal scanning.

Question 25

Phosphorylation of eukaryotic initiation factors can play both an inhibitory and stimulatory role in translational control of gene expression.

Question 26

Prokaryotic mRNAs contain a short RNA sequence upstream from the initiation codon called the ______________ sequence,which is complementary to a sequence on 16S rRNA.

Question 27

eIF4A is a member of the DEAD protein family that has RNA helicase activity.

Question 28

Most eukaryotic mRNAs have 5' caps that function in translation initiation instead of Shine -Dalgarno sequences found in prokaryotes.

Question 29

Translation initiation in eukaryotes involves scanning of the mRNA to locate a favorable AUG.

Question 30

Translational control is more common in prokaryotes than eukaryotes because prokaryotic mRNAs have a longer lifetime than eukaryotic mRNAs.

Question 31

eIF1 and eIF1A appear to encourage formation of a stable 48S complex by dissociating improper 40S and mRNA complexes.

Question 32

E.coli $\sigma$ ³² temperature sensitive expression is an example of transcriptional control.

Question 33

The let-7 miRNA blocks _________________ initiation in human cells.