Deck 15: Rna Processing II: Capping and Polyadenylation

Question 1

The capping substance for eukaryotic mRNAs is ______________.

Answer 1

7-methylguanosine

Question 2

___________ RNA is the only type of RNA to get polyadenylated.

Answer 2

Messenger

Question 3

Uncapped mRNA is much more stable then capped mRNA.

Answer 3

False

Question 4

Which of the following regions on calf-thymus poly(A)polymerase has been shown experimentally not to be necessary for its activity in vitro?

A)RNA binding domain
B)polymerase module
C)nuclear localization signals
D)serine/threonine rich regions
E)All domains are necessary.

Question 5

The cap plays a role in the removal of the ___________ intron while poly(A)tail plays a role in the removal of the ____________ intron.

Question 6

The poly(A)tail of eukaryotic mRNA is approximately ___________ nucleotides in length.

A)5
B)25
C)100
D)250
E)1000

Question 7

The 5' cap of mRNA helps protect the mature mRNA from degradation by ________.

Question 8

The human vaccinia virus replicates in the _________ of cells and therefore must carry with it its own capping enzymes.

Question 9

The fact that actinomycin D does not inhibit polyadenylation supports the fact that

A)polyadenylation occurs pre-transcription of mRNA.
B)polyadenylation occurs during transcription.
C)polyadenylation occurs post-transcription.
D)it happens in the nucleus.
E)it happens in the cytoplasm.

Question 10

Poly(A)polymerase can be found in the _____________ of a cell.

A)nucleus
B)cytoplasm
C)lysosomes
D)nucleus and cytoplasm
E)nucleus and lysosomes

Question 11

Please put the following steps of Cap synthesis in the correct order.(1)N⁷ of the capping guanine is methylated.(2)The terminal phosphate is removed from the pre-mRNA.(3)A capping GMP is added to the pre-mRNA.(4)The 2'O-methyl group of the penultimate nucleotide is methylated.

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

Question 12

Which of the following is NOT a function of the mRNA cap?

A)protects the mRNA from degradation
B)enhances translatability of the mRNA
C)enhances transport of the mRNA to the cytoplasm
D)enhances splicing of the mRNA
E)helps regulate expression of the mRNA

Question 13

At least 5 different cDNAs have been isolated for the enzyme poly(A)polymerase.These cDNAs are a result of alternative ___________ and ______________ of the poly(A)polymerase gene.

Question 14

Which of the following is not required for mammalian cell polyadenylation of pre-mRNA?

A)PAP
B)CPSF
C)PABII
D)RNA polymerase I
E)RNA polymerase II

Question 15

The function of a nucleotide phosphohydrolase is to ______________ phosphates from its substrate.

Question 16

Although snRNA U1 functions in the nucleus,it receives a 5' cap to enhance its

A)binding to snRNPs.
B)export to the cytoplasm.
C)export to the ER lumen.
D)export out of the cell.
E)binding to the mature mRNA.

Question 17

When does capping of the pre-mRNA occur?

A)It is the first nucleotide added by RNA polymerase.
B)It occurs before the mRNA reaches a chain length of 30 nt.
C)It occurs after the poly(A)tail has been added.
D)It occurs after splicing has occurred.
E)It occurs after export of the mRNA into the cytoplasm.

Question 18

The CTD domain of which subunit of RNA Polymerase II has been shown to be involved in pre-mRNA processing?

A)Rpb1
B)Rpb2
C)Rpb4
D)Rpb6
E)Rpb12

Question 19

Which of the following is the mRNA polyadenylation signal motif found in mammalian cells?

A)AAGAAA
B)AAUAAA
C)AAUGGG
D)UUAUUU
E)GGAUUU

Question 20

Cytoplasmic ___________ remove (A)s from the poly(A)tail.

Question 21

Polyadenylation is not required for efficient transport of mRNA out of the nucleus.

Question 22

Once the poly(A)tail is added to the mRNA it is very difficult to remove.

Question 23

The addition of poly(A)to mRNA seems to be important for its translatability.

Question 24

Once a mRNA loses its poly(A)tail,it is imported back into the nucleus.

Question 25

Poly(A)tails are added to the 5' end of the mRNA molecule.

Question 26

Pre-mRNA must be cleaved before it is polyadenylated.

Question 27

The 5' cap of mRNA has no effect on the translatability of the mRNA.

Question 28

Most genes do not encode for a poly(A)tail.

Question 29

Experiments using yeast as a model have shown that cleavage of the poly(A)tail is necessary for transcription termination.

Question 30

Pre-mRNA processing begins during transcription.

Question 31

RNA polymerase II transcription of a gene usually stops at the polyadenylation site.