Download Name: page1 of 7 pages MOLECULAR BIOLOGY BIO372S January

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MOLECULAR BIOLOGY
BIO372S
January 19, 2010
First mid-term examination
(one hour)
Read each question carefully and put your answers on the exam page only in
the spaces indicated.
Good luck!
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Signature:
Student Number:
ANSWERS IN BOLD GREEN, TYPE
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1. You are given two micrograms of plasmid DNA. There are four EcoRI
recognition-cut sites in the plasmid yielding four linear fragments. Two
of the fragments are of known sizes and two of the fragments are of
unknown sizes.
(10 points) What are the
sizes of the two unknown
fragments?
Answer here:
(10 points) How many
plasmid molecules were
there?
Answer here:
(Essential information:
base pair of DNA is 660
Daltons and Avogadro’s
number is 6.02 X 1023)
on
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page3 of 7 pages
Numbers 2 - 16, 15 questions, 2 points each (total of 30 points)
2.
A.
B.
C.
D.
E.
The chromosomal theory of inheritance holds that
chromosomes vary in size.
the number of chromosomes vary in individuals.
chromosomes contain histone proteins.
genes are arranged in a linear order on chromosomes.
chromosomes condense during mitosis.
3. Some genes located on the same chromosome do not show perfect linkage
because
A. they are too close together.
B. they are interrupted by other genes.
C. crossover events occur between homologous.
D. some genes are deleted.
E. too many alleles are present.
4.
A.
B.
C.
D.
E.
The relationship between genes and enzymes was shown by
Watson and Crick.
Beadle and Tatum.
Avery and McLeod.
Morgan and Mendel.
Miescher and Stern.
5. The early notion of one-gene/one-enzyme was not true because of which
of the following?
A. An enzyme can be composed of more than one polypeptide.
B. Many genes contain the information for making polypeptides that are not
enzymes.
C. The end products of some genes are not polypeptides.
D. An enzyme can be composed of more than one polypeptide, many genes
contain the information for making polypeptides that are not enzymes and
the end products of some genes are not polypeptides are all correct.
E. Only An enzyme can be composed of more than one polypeptide and many
genes contain the information for making polypeptides that are not enzymes
are correct.
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6.
A.
B.
C.
D.
E.
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Which of the following would not be considered a mutation?
permanent replacement of guanine with thymine in a DNA strand
deletion of a gene segment
insertion of an intron in the middle of an exon
permanent replacement of cytosine with adenine
crossing over of two gene regions during meiosis
7. A new insulin gene was isolated and a study was planned to look at the
function of the promoter region. Which of the following would be the best
choice for this study?
A. southern analysis
B. immunoblotting
C. reporter gene assay
D. PCR
E. immunoprecipitation
8. A DNA fragment was treated with EcoRI restriction enzyme. The
restriction pattern is shown below. How many fragments should be visible
on a Southern blot if radioactively labeled probe "1" was used?
A.
B.
C.
D.
E.
9.
A.
B.
C.
D.
E.
0
1
2
3
4
A major
measure
measure
measure
monitor
monitor
function of reporter gene assays is to
mutation rates of a gene.
transcriptional levels.
replication.
luciferase activity.
CAT activity.
10. Which of the following is not true about run-on transcription assay?
A. Isolated nuclei are used in the assay.
B. Cytoplasmic RNA is included in the assay.
C. The reaction is done in the presence of labeled nucleotide.
D. The assay can reveal the transcription rates of genes
E. Genes being transcribed can be identified.
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11. Which of the following isotopes would be the most appropriate for the
end-labeling of a DNA strand with a radioactive phosphate via
polynucleotide kinase?
A. α-32P
B. 35S
C. β -32P
D. γ -32P
E. 14C
12. The experimental system (organism) first used to look at the
relationship between genes and enzymes was
Neuropsora crassa
13. During translation, the genetic code in mRNA is "read" by
Codons or ribosomes
14. The process of making RNA from DNA is called
Transcription
15. Crossing over between two homologous chromosomes occurs during
prophase of meiosis I
16. In genome sequencing a “scaffold”:
-Represents a region of unbroken, overlapping nucleotide sequence reads.
-Contains sequence gaps.
-Represents a physically continuous segment of the chromosomal DNA.
-Is made up of contigs.
Circle the statements above that are true of scaffolds.
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16 (10 points). You have separate solutions of DNAs of increasing sequence
complexity: i) T4 bacteriophage, ii) E. coli DNA, and iii) yeast DNA. The
DNA is sheared to a uniform size of 200 bp. The DNA is thermally
denatured and then placed in standard conditions allowing renaturation.
Draw a plausible renaturation reactions for the three separate samples of
DNA.
Answer: three separate curves, fastest reassociating, T4, then E.
coli, then yeast
17 (10 points). You now combine the three samples above into one sample,
which is well mixed. The mixed DNA is now sheared to a uniform size of
200 bp. The DNA is thermally denatured and then placed in standard
conditions allowing renaturation. Draw a plausible renaturation reaction.
Must show ONE curve with three dips and three plateaus, the first dip for
T4, second for E. coli and the third for yeast.
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18 (10 points). Below is a density trace of a sample of DNA. Show a
plausible corresponding melt curve for the same DNA. Must show one melt
curve with an early rise due to the majority, light component of DNA,
followed by a plateau and a small rise due to the minority heavier
component.
Density trace
Melt curve
19 (10 points). Approximately how large is the genome of Neurospora
crassa?
About 40 million base pairs
20 (10 points). Jonathon Arnold in his commentary on the paper by Galagan
et al. (2003) states: "Unlike its yeast relatives, however, Neurospora
abhors repeated genes and other duplicated elements in the genome." This
effect is due to RIPing. Show the dinucleotide frequency ratio (NpN/NpN)
that best indicates RIPing:
TpA vs. ApT