Download 99( I )生技所分生考題,林富邦老師部分

99( I )生技所分生考題,林富邦老師部分
姓名______________
學號__________________
一 複選題 (注意：全答對才給分，部份答對不給分) 每題 5 分,合計 70 分
1.
The anticodon of a tRNA is 5'UUG. What codon(s) can be theoretically
recognized by this tRNA?
a. 5'CAA
b. 5'CAC
c. 5'AAC
d. 5' GAC
e. 5'CAG
2.
Components required for peptide chain initiation are:
a.
c.
3.
GTP.
b. 30S and 50S ribosomal subunits.
initiation factors.
d. f-Met-tRNAifMet.
e. mRNA.
The correct statements about the tRNA molecule with the anticodon 5'CAU are:
a. Its anticodon can theoretically base pair with up to three different codons.
b. The wobble base in the anticodon would be cytosine.
c. It is the anticodon for tRNAfmet.
d. Its anticodon can base pair to the codon 5'AUG.
e. All are correct.
4. What are true of the following statements about transfer RNA (tRNA) molecules
a. they contain a number of bases that have been modified
post-transcriptionally
b. they have extensive intrachain hydrogen bonding
c. the amino acid is attached to the 2' or 3' position of the 3'-terminal
adenosine
d. they have binding sites for a specific amino acid, a specific amninoacyl
transferase, the ribosome, and a specific codon on mRNA
e. they contain an anticodon triplet of bases at the 5' end of the moclecule that
is complementary to the triplet codon on messenger RNA (mRNA)
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5.
What are the correct following statements about amino acid activation
a.
b.
c.
d.
e.
6.
the activation step requires the hydrolysis of the terminal phosphate
group of GTP
the aminoacyl-tRNA synthetase is specific for a given amino acid
there may be more than one kind of tRNA for a given amino acid
aminoacyl-tRNA synthetases transfer the amino acid to the A on 3'end of
tRNA via an aminoacyl-AMP intermediate
once an amino acid is attached to a given tRNA the specificty for
recognition of the appropriate codon on mRNA is due entirely to the
tRNA, and not at all to the amino acid
The folding cycle in the GroES-GroEL complex of E. coli utilized the following
sequences are:
a. GroES is recruited to GroEL
b. GroES dissociates from the complex
c. Partially folded protein hydrophobic residues bind GroEL
d. GTP binding to GroEL
e. GroES promotes ATP hydrolysis and -subunits undergo a
conformational change that buries the hydrophobic patches
7.
Ubiquitination of proteins for degradation involves the following sequences:
a.
b.
c.
d.
e.
8.
ubiquitin-activating enzyme (E1) attaches via GTP-dependent
formation of thioester bond to C-termini of ubiquitin,
ubiquitin-protein ligase (E3) transfers ubiquitin to free amino
groups on the protein,
E3 selects a protein for degradation by the nature of the N-terminal
amino acid,
ubiquitin-carrier protein (E2) picks up ubiquitin,
multiple ubiquitinations may occur on a protein substrate,
What are characteristics of chaperonins:
a. formed of two stacked rings of subunits.
b. large, cylindrical protein complexes.
c. sequester partially folded proteins.
d. allow folding to proceed in a protected environment.
e. ATP hydrolysis are involved
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9.
Characteristics of protein translocation systems include:
a.
b.
c.
d.
e.
pre-proteins are maintained in a loosely folded, translocation-competent
conformation through interaction with molecular chaperones.
membranes involved in translocation have specific protein receptors
exposed on their cytosolic faces.
translocons catalyze movement of the proteins across the membrane and
metabolic energy in the form of GTP only is essential.
proteins to be translocated are made as pre-proteins containing
contiguous blocks of amino acid sequences that act as sorting signals.
translocons are usually composed of heteromeric proteins
10. The forms of post-translational processing are:
a. limited proteolytic cleavage.
b. signal sequences removal.
c.
d.
e.
phosphorylation.
lipid addition.
glycosylation
11. Characteristics of control mechanisms that regulate transcription in prokaryotes
are:
a. DNA : protein interactions are central to transcription regulation.
b.
c.
d.
e.
protein : protein interactions are an essential component of transcription
regulation.
regulatory proteins commonly bind DNA at sites of at least partial dyad
symmetry or inverted repeats.
regulatory proteins might undergo reversible conformational changes.
regulatory proteins receive cues that signal the status of the environment of
the cell.
12. The genetic code has the following characteristics:
a.
b.
c.
d.
e.
It is not overlapping.
It is read 3' to 5'.
It is read from a fixed starting point without punctuation.
It is degenerate.
A group of three bases codes for one amino acid
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13. GTP hydrolysis is essential for the following:
a.
b.
c.
d.
e.
the formation of the initiation complex (translationally active 70 S ribosome
complex).
the elongation step of translation.
the translocation step of translation.
the binding of release factors to the ribosome.
Chaperones Hsp40-Hsp70 binding cycle.
14. Proteolytic cleavages have been shown to be involved in the following
processes:
a. inactivation of lacI repressor.
b.
c.
d.
elimination of the N-terminal Met residue.
activation of zymogens.
elimination of signal sequences after the protein has reached its proper
e.
location.
CRP activation by cAMP.
二 單選題 (每題 2 分 共 30 分)
1. When the cellular level of tryptophan decreases in E. coli:
A. tryptophan-bound Trp repressor associates with trp operator.
B. trp repressor has a greater affinity for trp operator.
C. tryptophan binds trp inducer to promote positive control of trp promoter.
D. Trp aporepressor has lowered affinity for trp promoter allowing RNA.
polymerase binding and transcription of the trp operon.
E. none of the above.
2. How many high-energy phosphoric anhydride bonds per amino acid for the energy
expenditure for protein synthesis
A. 4
B. 3
C. 2
D. 1
E. 0
3. Termination of translation in prokaryotic cells requires:
A. binding of the terminator tRNA to the termination codon.
B. displacement of EF-G by EF-Tu:aminoacyl-tRNA
C. ternary interaction of the release factor and the termination tRNA with the
termination codon.
D. release factor interaction with the Shine-Dalgarno sequence and
subsequent dissociation of the two ribosomal subunits.
E. interaction of release factors with the termination codon.
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4. Eukaryotic secretory proteins are synthesized and translocated via the endoplasmic
reticulum. Order the following sequence of events for this process.
A. signal sequence removed.
B. glycosylation in the ER lumen.
C. signal sequence synthesis on ribosomes.
D. SRP binds signal sequence and subsequently binds SRP-receptor.
E. ribosome dissociates.
A. A, C, E, B, D
B. A, C, B, D, E
C. C, A, D, B, E
D. C, D, A, B, E
E. C, B, D, E, A
5. Translation of a synthetic polyribonucleotide containing the repeating sequence
CAA in a cell-free protein-synthesizing system produced three homopolypeptides:
polyglutamine, polyasparagine, and polythreonine. If the codons for glutamine and
asparagine are CAA and AAC, respectively, which of the following triplets is a codon
for threonine?
A. ACA
B.
CAA
C.
CAC
D. CCA
E. ACC
6. Cyclic AMP regulates the lac operon by
A. binding to the operator to turn on transcription
B. binding to the lac repressor to prevent transcription
C. combining with the catabolite activator protein to remove the latter's
D.
E.
inhibition of transcription
combining with the catabolite activator protein (CAP) to from a complex,
which turns on transcription by binding to the promoter
none of the above
7. DNA contains sequences of bases known as promoters which
A. are recongnized by the core enzyme of RNA polymerase
B. are not functional in prokaryotes
C. are single-stranded regions of the duplex DNA
D. are transcribed into RNA sequences
E. occur in the chain just before the message sequence that defines the message
RNA (mRNA)
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8. Which of the following mutations would be most likely to have a harmful effect on
an organism?
A. a base-pair substitution
B. a deletion of three nucleotides near the middle of a gene
C. a single nucleotide deletion in the middle of an intron
D. a single nucleotide insertion downstream of, and close to, the start of the
coding sequence
E. a single nucleotide deletion near the end of the coding
9. The appropriate order for the basic steps of protein synthesis are:
A. The elongation reaction transfers the peptide chain from the peptidyl-tRNA in the P
site to the aminoacyl-tRNA in the A site.
B. The P site is occupied by peptidyl-tRNA carrying the growing polypeptide chain.
C. Binding of mRNA by the small subunit followed by association of a particular
D.
E.
A.
D.
initiator aminoacyl-tRNA that recognizes the first codon.
The large ribosomal subunit joins the initiation complex, preparing it for the
elongation stage.
The new, longer peptidyl-tRNA moves from the A site into the P site as the ribosome
moves one codon further along the mRNA.
A, C, E, B, D
B. C, D, B, A, E
C. C, D, A, B, E
D, C, E, B, A
E. B, E, C, D, A
10. Which of the following is TRUE about cII protein?
A. causes inhibition of RNA polymerase activity at the PRE promoter
B. is required for RNA polymerase activity at the PRE promoter
C. acts as a negative regulator
D. Both A and B
E. All of the above
11. Transcription from PRE promotes lysogeny by causing cI mRNA to be translated
into repressor protein and __________.
A. by causing transcription to proceed through cro backwards
B. inhibiting transcription through PRM
C. That is the only mechanism by which it promotes lysogeny
D. All of the above
E. None of the above
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12. Which of the following is required for lytic development?
A.
B.
C.
D.
E.
P anti-Q
Q mRNA hybrid with antisense Q
Q protein
All of the above
None of the above
13. Which of the following statements is FALSE?
A. Cro protein prevents transcription of PRM preventing the synthesis of
lambda repressor.
B. Cro protein inhibits the expression of early genes from both PL and PR.
C. Cro protein binds to the same operators as the lambda repressor.
D. Cro protein has a higher affinity for OR3 than OR2 and OR1.
E. None of the above
14. Operons are a(n) ____________ sequence lying adjacent to the DNA being
transcribed and are composed of a promoter located next to a(n) _______ that
interacts and is controlled by a(n) _______ protein.
A. initiation; operator; repression B. operator; repressor; regulatory
C. regulatory; repressor; activator D. regulatory; operator; regulatory
E. none are true
15. The recurring structural feature in DNA-binding proteins is the presence of
____________ segments that fit into the _______ grove of B-DNA.
-helix; major
D-barrel; minor
-sheet; major
E. all are true
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C. -turn; minor