Download Protein Synthesis Questions

Protein Synthesis Questions
Multiple Choice
____
1. Which of the following correctly describes the order in which cell components become involved in
protein synthesis?
a. DNA polymerase, mRNA, ribosome, tRNA
b. mRNA, RNA polymerase, ribosome, tRNA
c. RNA polymerase, mRNA, tRNA, ribosome
d. RNA polymerase, mRNA, ribosome, tRNA
e. DNA, rRNA, tRNA, mRNA
____
2. DNA acts as a template for transcription. Which of the following statements regarding the DNA of a
gene being expressed is true?
a. After unwinding, both of the DNA strands act as templates.
b. After unwinding, only one of the DNA strands acts as a template.
c. The two strands only act as a template when paired.
d. In prokaryotes, the binding of RNA polymerase to unwound DNA occurs randomly on
either of the two strands.
e. The strand with the higher cytosine-guanine content acts as the template.
____
3. RNA polymerase participates in
a. DNA replication
b. RNA replication
c. DNA transcription
d. RNA transcription
e. RNA translation
____
4. The splicing of the first-formed mRNA transcript by spliceosomes is necessary because
a. the poly-A tail must be added
b. introns need to be added
c. the poly-A tail and the cap must be removed
d. the transcript must be freed from the DNA
e. introns need to be removed
____
5. The 'Central Dogma' states that the flow of genetic information is in the direction
a. protein, RNA, protein
d. RNA, DNA, protein
b. RNA, DNA, RNA
e. DNA, RNA, protein
c. protein, RNA, DNA
____
6. The function of the polyadenine tail that is added to mRNA in eukaryotic cells is to
a. prevent degradation of the mRNA
b. initiate the binding of the mRNA to the ribosome
c. help the mRNA to bind to a pore in the nuclear membrane
d. add a specific amino acid sequence to the polypeptide produced
e. act as a signal for the termination of translation
____
7. A certain protein needs to have a high energy phosphate group added to it in the cytoplasm before it
becomes active. This offers the possibility of control at which of the following levels?
a. transcriptional
d. translational
b. operational
e. post-translational
c. post-transcriptional
____
8. In
a.
b.
c.
____
9. The arrangement of bases in a molecule of mRNA is best described as
a. branched
d. linked into a beta-pleated sheet
b. linear
e. circular
c. paired
a eukaryotic cell, the sizes of the large and small ribosome subunits are, respectively
50S, 40S
d. 80S, 60S
60S, 50S
e. 80S, 70S
60S, 40S
____ 10. A section of mRNA 9 codons long would most likely result in the addition of how many amino acids to a
growing polypeptide (the stop codon is absent)?
a. 9
d. 27
b. 5
e. 3
c. 10
____ 11. Line A below shows the peptide synthesized after transcription and translation of a piece of DNA. Line
B shows the peptide synthesized after a mutation in this piece of DNA.
A. proline - arginine - aspartic acid - lysine - glycine
B. proline - glutamine - aspartic acid - lysine - glycine
The type of change in the DNA most likely to be responsible for the difference between the peptides
is
a. a frame-shift mutation
d. a base deletion
b. a base insertion
e. a silent mutation
c. a base substitution
____ 12. If transcription could proceed in both directions along both DNA strands of a gene, how many
different polypeptides could be coded for by a single gene?
a. 1
d. 4
b. 2
e. 5
c. 3
____ 13. Suppose a tRNA molecule bearing the anticodon for cysteine, and with cysteine bound to it, is
chemically treated so as to change the cysteine to alanine (the tRNA molecule and the anticodon remain
unaltered). Which of the following is likely to be true?
a. Alanine would be incorporated into the peptide in place of cysteine.
b. Cysteine would continue to be brought to the ribosome by this tRNA.
c. Transcription would stop when this tRNA molecule entered the ribosome.
d. The amino acid bound to this tRNA would not be added to the growing polypeptide.
e. The result would differ in prokaryotes and eukaryotes.
____ 14. What is the amino acid sequence of the peptide that would be synthesized after transcription and
translation of the following piece of template strand DNA?
Hint: In what direction does protein synthesis occur?
5’-TCATGCGCAACA-3’
Codon
AGU
ACG
CGU
UGU
UGC
GCA
UGA
a.
b.
c.
d.
e.
Amino Acid
Ser
Thr
Arg
Cys
Cys
Ala
Stop
Ser-Thr-Arg-Cys
Ser-Thr-Arg-Stop
Cys-Cys-Ala-Cys
Cys-Cys-Ala-Stop
Ser-Ala-Arg-Stop