MBG 2040 Lecture Notes - Open Reading Frame, Plant Cell, Catabolite Activator Protein
24 Oct 2018
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1
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MBG*2020 Introductory Molecular Biology
Midterm Examination, W2010
March 04, 5:30-6:45 pm
Instructors: Prof. K. Yankulov Time: 75 minutes
Prof. R. Lo
The midterm consists of two parts: A is worth 20 marks. B is worth 20 marks.
Part A consists of 20 multiple choice questions. Answer questions 1 to 20 on the computer test
scoring sheet. Mark your answers on the test scoring sheet in PENCIL ONLY. Please note that
only the test score sheet is graded for questions 1 to 20 inclusive.
PART B consists of 5 short answer questions, 21 to 25. Answer these questions in the space
provided. Questions answered in pencil will not be re-graded. Please do not use red ink.
THE UNIVERSAL GENETIC CODE
______________Second Position__________
First Position 5’ end U C A G Third Position 3’end
U
Phe
Phe
Leu
Leu
Ser
Ser
Ser
Ser
Tyr
Tyr
Stop
Stop
Cys
Cys
Stop
Trp
U
C
A
G
C
Leu
Leu
Leu
Leu
Pro
Pro
Pro
Pro
His
His
Gln
Gln
Arg
Arg
Arg
Arg
U
C
A
G
A
Ile
Ile
Ile
Met
Thr
Thr
Thr
Thr
Asn
Asn
Lys
Lys
Ser
Ser
Arg
Arg
U
C
A
G
G
Val
Val
Val
Val
Ala
Ala
Ala
Ala
Asp
Asp
Glu
Glu
Gly
Gly
Gly
Gly
U
C
A
G
MARK MARK MARK TOTAL
Q 21. Q 23. Q.25
Q 22. Q 124.
2
PART A consists of 14 multiple choice questions. Answer questions 1 to 20 on the computer test
scoring sheet in PENCIL ONLY. Only the test score sheet is graded for questions 1 to 20
inclusive.
1.Based on the experiments of Avery, MacLeod and McCarty, which combination will NOT produce
type IIIS colonies of Streptococcus pneumoniae (hint: transforming principle)?
a) IIR cells plus heat-killed Type IIIS cells
b) IIR cells plus DNase treated heat-killed Type IIIS cells
c) IIR cells plus protease treated heat-killed Type IIIS cells
d) IIR cells plus RNase treated heat-killed Type IIIS cells
e) More than one of the above.
2. Each carbon of a deoxyribose sugar has a hydrogen atom attached. Besides the hydrogen, a
deoxynucleoside triphosphate has a _______ attached to the 1’ carbon, a ______ attached to
the 2’ carbon, a ______ attached to the 3’ carbon and a ______ attached to the 5’ carbon.
a) phosphate, OH, OH, base
b) base, OH, OH, phosphate
c) base, H, OH, phosphate
d) base, OH, H, phosphate
e) phosphate, OH, H, base
3. Which of the following statements regarding telomerase is correct?
a) Telomerase extends the parent strand using 5’ to 3’ polymerase activity.
b) The polymerase activity of telomerase does not require a 3’OH for nucleotide addition.
c) The polymerase activity of telomerase does not require a template.
d) Telomerase synthesizes RNA.
e) More than one of the above is correct.
4. The diagram to the right illustrates a transcription
bubble. Two ends have been labeled “A” and “B”.
Are they 5’ or 3’ ends?
A B
a) 5’ 3’
b) 5’ 5’
c) 3’ 5’
d) 3’ 3’
e) It is not possible to determine the ends using the information provided.
3
5. Which of the following statements regarding the E. coli RNA polymerase is correct?
a) The core enzyme includes the σ factor.
b) The σ factor is responsible for recognizing sequences within the promoter to initiate
transcription.
c) The holoenzyme is responsible for transcription elongation.
d) The σ factor is responsible for unwinding the DNA strands during elongation.
e) More than one of the above is correct.
6. A poly(A) tail is
a) added to the 3’ end of prokaryotic transcripts.
b) removed from the mRNA by the spliceosome before translation begins.
c) the result of the post-transcription addition of adenine residues by ribosomes.
d) the result of the post-transcription addition of adenine residues by poly(A) polymerase.
e) More than one of the above is correct.
7. Which of the following statements regarding spliceosome-mediated splicing of introns is
incorrect?
a) Spliceosomes are composed of snRNAs and proteins.
b) snRNPs work in concert to excise introns and splice the exons.
c) The 3’ end of exon 1 is covalently attached to the 5’ end of exon 2.
d) The 5’ end of exon 1 is covalently attached to the 3’ end of exon 2.
e) More than one of the above.
8. Which of the following components is NOT involved in the translation of prokaryotic
mRNA?
a) Shine-Dalgarno sequence
b) promoter
c) stop codon
d) ribosome
e) release factor
9. Which of the following would be a component of a polycistronic prokaryotic mRNA?
a) A single stop codon located near the 3’ terminus of the mRNA.
b) A 7-methylguanosine cap at the 5’ terminus of the mRNA.
c) A single promoter sequence.
d) Multiple Shine-Dalgarno sequences.
e) More than one of the above.
