Deck 25: Information Decoding: Translation and Post-Translational Protein Processing

Question 1

Which of the following applies only to prokaryotic proteins?

A) Secreted proteins have signal sequences in their N-terminal regions.
B) Some proteins are covalently modified after translation.
C) Hydrophilic proteins are able to either traverse or become embedded in hydrophobic membranes.
D) Some proteins are synthesized on polyribosomes.
E) Translation is coupled to transcription.

Answer 1

E

Question 2

An ________ is a sequence within an mRNA that is bounded by stop and start codons that can be continuously translated.

Answer 2

open reading frame

Question 3

The genetic code is universal for all organisms and organelles.

Answer 3

False

Question 4

Differences between eukaryote and prokaryote translation include the 40S ribosome recognizing the ________ rather than a Shine-Dalgarno sequence and the N-terminal amino acid is ________.

Question 5

Translation is an RNA-directed process whereby amino acids are specified by ________ on the mRNA, which are complementary to ________ on aminoacyl tRNAs.

Question 6

Peptide bond formation requires GTP hydrolysis.

Question 7

The anticodon ends of tRNAs contact the ________ subunit and the acceptor ends contact the ________ subunit of the ribosome.

Question 8

Which of the following statements about initiation of translation in bacteria is FALSE?

A) fMet-tRNAfMet is the only charged tRNA that can bind to the 30S subunit on its own.
B) The formyl group is transferred to Met-tRNAfMet from 10-formyl-tetrahydrofolate.
C) Three initiation factor proteins are required to bind the mRNA and the initiator tRNA to the 30S ribosome.
D) Pairing between mRNA and rRNA places the initiation codon next to the P site in the ribosome.
E) The complete 70S initiation complex ready to receive a second charged tRNA is assembled without any GTP hydrolysis.

Question 9

Aminoacyl-tRNA synthetases do not contribute to the fidelity of translation.

Question 10

Which of the following statements is FALSE?

A) There does not need to be as many different tRNA types as there are codons.
B) The modified bases in the tRNAs are added during transcription.
C) The amino acid is attached at the 3' terminus of the tRNA.
D) The 3D structures of all tRNA molecules are such that they fit equally well into the ribosome.
E) tRNA exhibits unusual base pairing including single bases pairing with two others.

Question 11

Termination of translation occurs when a stop codon is translocated into the ________ site of the ribosome.

Question 12

Which of the following BEST describes the transport of nuclear proteins across the nuclear membrane?

A) Simple diffusion
B) An N-terminal targeting sequence that is cleaved during transport
C) A targeting sequence that interacts with a carrier protein
D) Vesicular transport followed by delivery via fusion with the nuclear membrane
E) Co-translational transport using ribosomes attached to the membrane

Question 13

In the secondary structure of ribosomal RNA, the regions of self-complementarity are highly ________.

Question 14

Which of the following statements about translation elongation in bacteria is TRUE?

A) Charged amino acids are escorted to the A site of the ribosome by an initiation factor.
B) The growing polypeptide chain is moved from the A site to the P site before peptide bond formation.
C) GTP hydrolysis occurs after moving the aminoacyl-tRNA into the A site and before peptide bond formation.
D) The entire peptidyl-tRNA is translocated from the P site to the A site during peptide bond formation.
E) The uncharged tRNA leaves from the E site as the ribosome moves one codon in the 5' direction.

Question 15

Antibiotics that inhibit translation are useful because:

A) the translational machinery of eukaryotes is sufficiently different to that of bacteria.
B) microorganisms can develop resistance to other antibiotics.
C) antibiotic resistance genes are often carried on plasmids rather than the bacterial chromosome.
D) different antibiotics can inhibit different steps of translation.
E) they do not cross the cell membrane in higher animals.

Question 16

Which of the following does NOT apply to proteins synthesized on the rough endoplasmic reticulum?

A) Signal recognition particle
B) Vesicular transport
C) Signal sequence cleavage
D) Continuous translation
E) Docking protein

Question 17

Which of the following BEST explains the "wobble" hypothesis proposed by Francis Crick?

A) The genetic code is degenerate in that most amino acids have more than one codon.
B) The genetic code is ambiguous in that each codon can specify more than one amino acid.
C) The anticodon can pair with any part of the corresponding codon.
D) The 5' base of the anticodon can make non Watson-Crick hydrogen bonds with several different bases at the 3' position of the codon.
E) Inosine can pair up with A, U, or C.

Question 18

The bacterial Shine-Dalgarno sequence aligns the mRNA with the 16S rRNA to start translation at the correct position.

Question 19

Termination of translation requires GTP hydrolysis and direct interaction of a release factor with a termination codon.

Question 20

Glycosylated proteins are synthesized on rough endoplasmic reticulum.

Question 21

The fusion of vesicles, from the Golgi complex, with specific membranes is facilitated by ________ protein pairs called t-SNARES and v-SNARES on membranes as well as cytosolic fusion proteins.

Question 22

Nuclear encoded proteins destined for ________, chloroplasts or nuclei are synthesized in the cytoplasm.