Zoo/Bot 3333
Genetics
4/21/13
Quiz 4
For answers to the quiz, click here
Questions 1-3 pertain to the following. The ability to find and access information is critical to both scholarship and
professional development, and the first three questions below will require you to go to ‘extramural’ sources to find
answers to questions relevant to topics we have recently been discussing in lecture (or will soon discuss). They are not
in your textbooks.
1. This week, a case before the Supreme Court considered whether human genes were patentable. The arguments
before the Court considered:
a) whether a Salt Lake City Company has patent rights to the BRCA1 gene; b) the Federal Court of Appeals verdict
which sided against granting patents; c) arguments from the MIT biologist Eric Lander, who felt that denying patents
would stifle research; d) all of the above; e) none of the above.
2. The genome of an aquatic vertebrate, once believed to have gone extinct 70 million years ago, was recently
sequenced by the Broad Institute. Which of the following are true?
a) it is the only existing species of its genus; b) the genetic changes accumulating in protein coding genes over time in
this organism are much lower than observed for other vertebrates; c) this species is the closest living relative to
tetrapods; d) all of the above; e) none of the above.
3. Ricin:
a) is a plant toxin derived from rice pericarp; b) was recently detected in letters that were delivered to the White House;
c) results in a depurination event in the 28S ribosomal RNA, inhibiting protein synthesis; d) all of the above; e) none of
the above.
4. During E. coli DNA replication, which of the following is a function of DNA gyrase:
a) opens up the replication bubble at the origin of replication; b) unwinds DNA at the replication fork; c) relieves
torsional stress by introducing negative supercoils in advance of the replication fork; d) all of the above; e) none of the
above.
Questions 5-6 pertain to the figure on the right. DNA
was prepared from white blood cells isolated from a large
human population. These DNAs were individually
digested with EcoRI, subjected to electrophoresis and
Southern blotting, and the blot was probed with a
radioactively labeled cloned DNA sequence. Ten different
individuals were analyzed for their patterns. The figure
below indicates the results from these ten individuals.
5. In the diagram on the right, the vertical lines
represent EcoRI restriction sites. An asterisk over the
site represents a polymorphism (presence or absence of
the site in individuals) in the population. The double
arrow above the DNA represents the boundaries of the
cloned DNA used as a probe in the Southern blot
analysis. Which of the following is consistent with the
arrangement of EcoRI restriction sites in human
genomic DNA?
*
a)
1.6
c)
2.3
*
b)
4.1
*
1.6
2.3
1.6
2.3
e)
4.1
*
d)
*
1.6
2.3
*
*
1.6
4.1
2.3
4.1
6. Which of the above individuals (1-10) would represent an individual that carried chromosomes that were
heterozygous for the distribution of restriction sites in this area (i.e. homolog chromosomes with different restriction
site patterns)?
a) individual 1; b) individual 2; c) individual 3; d) all of the above; e) none of the above.
4.1
The accompanying table shows the presence or absence of seven sequence-tagged sites (STS’s) numbered 1-7, in each
of seven BAC clones, designated A-G. A “+” in the table means that PCR primers specific to the STS are able to
amplify the sequence from the clone, a “-“ means that the sequence can not be amplified from the clone.
STS marker
BAC Clone
A
B
C
D
E
F
G
1
+
-
2
+
+
+
+
-
3
+
+
4
+
+
+
-
5
+
+
+
+
6
+
+
+
-
7
+
7. The relative order of the STS sites within the cloned genome can be ordered as:
a) 1462537; b) 4165237; c) 7352164; d) 7251643; e) 1347256
Questions 8-9 pertain to the following diagram, which represents a region of a
DNA sequencing gel produced using the Sanger chain termination method. The
individual lanes represent the reaction products from the four separate labeling
reactions (A,G,C,T) which were loaded at the top of the gel.
8. As deduced from this experiment, the sequence
of the strand being copied (i.e. template strand) in this reaction is:
a) 5’-AGACTATCTCTA-3’
b) 5’-ATCTCTATCAGA-3
c) 5 -TAGAGATAGTCT-3’
d) 5- TCTGATAGAGAT-3’
e) 5- GAGTCGCTCTCG-3’
9. Which of the following was NOT present in the test tube during the ‘A’ DNA synthesis reaction?
a) dATP; b) dGTP; c) ddATP; d) dTTP; e) all of the above were present in the reaction.
Question 10 pertains to the following. Six independently derived mutants are recovered in Neurospora which are all
unable to grow unless supplemented with compound Z. The mutants are then grown on minimal media supplemented with
one of 6 chemicals all believed to be precursors to compound Z. A summary of the ability of the mutants to grow on
media containing these chemicals is indicated below, where a “ +” sign indicates growth and a “ -” sign indicates no growth.
precursors added to minimal medium
mutant number
A
B
C
D
E
F
Z
1
+
+
+
-
-
-
+
2
+
+
+
+
-
-
+
3
+
+
+
+
+
-
+
4
-
-
+
-
-
-
+
5
-
-
-
-
-
-
+
6
-
+
+
-
-
-
+
10. From the above chart, the enzyme that catalyzes the production of compound C appears to be mutant in strain:
a) 1; b) 2; c) 3; d) 4; e) none of the above.