Download Final Exam KEY

Biol 200, Autumn 2014
Final Exam
*****KEY*****
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This exam is worth 110 points. The exam has a total of 7 pages. Pages 2-7 have questions.
Honor Code Agreement - Signature: ________________________________ Date: ____________
(You agree to not accept or provide assistance to anyone else during this exam.) Thank you!
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Please turn in your exam to your TA when you are finished and quietly leave the room.
The key will most likely be posted later this afternoon.
Graded final exams will be available sometime the week of December 15th. They can be picked up in
Hck 302 with a UW ID and will be available through the third week of January.
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This page is for reference only. Nothing will be graded on this page.
A
B
C
D
Page #
Codon Table
1
Points
Points
possible earned
2
16
3
28
4
26
5
15
6
15
7
10
Exam
Total
110
Biol 200, Autumn 2014
Final Exam
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1. (16 pts) The cartoon to the right represents a cross-section
through a developing chick embryo after body folding has
been completed.
a. (1) Which side of this section is dorsal? (Circle one) R S
b. (2) Which structures could be made from "C"? (Circle ALL
possible answers)
- lining of lungs
- brain
- blood cells
- skin cells
N
R
A
(blue)
B
(blue)
C
(red)
D
(green)
S
- muscles
c. (1) Which letter(s) represent endodermal layers? (Write all correct letters) D
d. (3) In an adult vertebrate, are either of the spaces inside B and/or D connected to the outside
world? Explain in a few words.
The space inside D is connected to the outside world through the mouth and anus, and is the
digestive tract. The space inside B is not connected to the outside world.
e. (1) Which letter(s) represent tissue in which some
cells have expressed the "noggin" protein? (Write all correct letters) C
f. (2) Which letter(s) represent tissue with cells that
will continue to divide in later stages of development? (Write all correct letters) A,B,C,D
g.(2)At this stage, most cells in the embryo are: (Circle ONE) totipotent
pluripotent
differentiated
h. (2) The cells in this embryo are sticking together as a multicellular organism. Choose one of the
types of biological macromolecules below and explain how that type of molecule helps with cells
sticking together in a few words.
carbohydrates
lipids
nucleic acids
proteins
The extracellular portion of membrane proteins can form hydrogen bonds, ionic bonds, or
hydrophobic interactions to keep cells together.
(Alternatively, you could suggest carbohydrates or proteins of extracellular matrix)
2
i. (1) What developmental process does the diagram
to the right show?
gastrulation
j. (1) Which group of cells (1 or 2) in this diagram are
more likely to become cells of the embryo in the
diagram at the top of the page?
(Circle ONE) 1 2
2
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Biol 200, Autumn 2014
Final Exam
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2. (12 pts) Place an "X" in the blank for the bigger structure in each pairing. (2 points each)
_____ an RNA polymerase molecule vs. a follicle cell __X___
_____ a Na+ ion vs. a phospholipid molecule __X___
____X_ a mitochondrion vs. a ribosome _____
_____ an allele vs. a chromosome _X____
___X__ a β-galactosidase molecule vs. a galactose molecule _____
___X__ a red blood cell vs. a free antibody _____
3. (10 pts) Read each description in the table and choose names or descriptions from the list on the
right that match (A-H). There is at least one answer for each description and there may be more than
one for some. Write ALL correct answers. Not all the choices will necessarily be used.
2 points each
Choices:
Description:
Answer(s):
A. Totipotent
a. Cells expressing BMP-4.
B, G
B. Pluripotent
b. A large cell that can engulf a virus coated in
C. Differentiated
C, E, H
antibodies.
D. Red blood cell
E. Macrophage
c. A cell that when activated starts dividing
C, F, H *
F. B-cell
mitotically and undergoes hypermutation.
G. Derived from ectoderm
d. Notochord cells during neurulation.
B, H
H. Derived from mesoderm
e. A cell that has rhesus factor (Rh) in its membrane.
C, D, H
*Note: We also accepted "B" for part c (if chosen instead of C). Although B-cells are considered
differentiated cells, it would have been reasonable to choose pluripotent since after activation some
daughter cells turn into "memory B cells" and others "plasma cells" which are different cells.
4. (6 pts) Filled-in symbols in the pedigree on the front page represent individuals with "Disease Q". It
is caused by a mutation in "Gene Q" which is located right next to "polymorphic locus A" (PLA) on
the same chromosome. The gel shows 4 different alleles (100, 300, 400 and 700 bp) of PLA amplified
using PCR primers specific for that locus. II-3 has an unexpected PLA genotype.
a. (3) Considering all information in the diagram, which of the following are possible modes of
inheritance of Disease Q? (Circle all possible modes)
- Autosomal dominant
- Autosomal recessive
- X-linked recessive
- X-linked dominant
b. (1) Which allele of PLA is inherited with the disease from the father to II-2? 100 bp
c. (2) Place an 'X' in the blank for all possible explanations for II-3's unexpected genotype.
_____ The DNA taken from II-3's cheek cells was contaminated with bacterial DNA
__X___ There was a non-disjunction event during meiosis I in I-1.
_____ There was a non-disjunction event during meiosis I in I-2.
_____ There was a non-disjunction event during meiosis II in I-1.
_____ There was an insertion mutation during spermatogenesis in I-2.
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Biol 200, Autumn 2014
Final Exam
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5. (26 pts) The diagram to the right shows the
position and structure of the "Androgen
Receptor" (AR) gene and protein. The
androgen receptor binds to testosterone,
a steroid hormone. When bound to
testosterone, the androgen receptor is
transported into the nucleus where it
binds to enhancer regions of genes required
for spermatogenesis (as well as other genes).
exons
?
a. (2) Where is the androgen receptor found in the
cell before testosterone binds? (Circle ONE)
- in the plasma membrane
DNA binding
domain
testosterone
binding
domain
- in the cytoplasm
b. (2) Exon 4 codes for a nuclear localization sequence (NLS).
What protein will bind to the NLS of the androgen receptor? importin
c. Which of the R-groups (from the front page) is most likely…
… (2) to be found at highest levels in the testosterone binding domain? (Choose ONE) A
… (2) to be found at highest levels in the DNA binding domain? (Choose ONE) C
d. (2) Which molecule below most likely interacts with the region labeled '?', based on the androgen
receptor's function. (Choose the one best answer)
- glucose
- basal transcription factor
- ATP synthase
- cAMP
e. The two mutant alleles below cause "Androgen Insensitivity Syndrome" (AIS) where XY
individuals are not able to produce sperm (along with other phenotypic changes in XX and XY
individuals).
Mutant allele A = Insertion of 25 base pairs in exon 1
Mutant allele B = Missense (single amino acid substitution) mutation in exon 3
i. (3) Which mutant is detectable using PCR and gel electrophoresis? A
ii. (3) Which mutant is more likely to affect the receptor's ability to bind
testosterone? Explain in a few words.
Mutant allele A, because it is a frame shift and will alter all of the
protein from that point to the C-terminus, which includes the testosterone
binding domain.
f. (2) Shaded symbols in the pedigree are individuals
with AIS. Is AIS recessive or dominant? recessive
g. (6) Give the appropriate genotype for each of the following individuals. Make sure to consider all
the information on this page.
(Dominant = "A" and Recessive = "a" )
I-2: XAXa II-1: XaY II-3: XAY 2 points each
h. (2) What is the chance that a sister of III-1 will carry an allele for AIS? 50%
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Biol 200, Autumn 2014
Final Exam
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6. (15 pts) Sarah's body contains a B-cell that contains the following sequence of DNA, which codes
for a heavy chain that binds to Rh factor. The promoter for this gene is to the right of the +1 site.
+1
5’
3’
A strand
ATAGGCCTGACTCGCGTAGATTTCATACTGATGCCCTAGCTACTCCAGATCCTA
TATCCGGACTGAGCGCATCTAAAGTATGACTACGGGATCGATGAGGTCTAGGAT
a. (1) Which strand is the template strand? (Circle ONE)
A
3’
5’
B strand
B
b. (2) Write the sequence of the first six nucleotides of the mRNA, and label the 5' and 3' ends.
Version A: 5'CUAGGG3' Version B: 5'AGUAAA3'
c. (3) Write the sequence of the first two codons in the transcribed mRNA, and label the 5' and 3'
ends.
Version A: 5'AUGAAA3' Version B: 5'AUGUCG3'
d. (6) Consider the heavy chain peptide that this gene encodes. Choose two of the bond types listed
below by putting an "X" in the blank, then describe a specific way that type of bond is or could be
involved in either B-cell receptor/antibody structure or function.
_____ Ionic Ionic bonds could form between the variable region and the antigen.
_____ Covalent
Disulfide bonds (which are covalent) are critical for holding the heavy and light
chains of the BCR/antibody together.
_____ Hydrogen H-bonds are critical for holding the beta-sheets of the heavy chain's secondary
structure. H-bonds could also be involved in the antibody-antigen interaction.
e. (3) Sarah’s mother is A- and her father is O+ and her sister is O+ (see pedigree). Considering all of
the information on this page, which of the following do you know are true? (Write an "X" in the
blank of each true statement)
___X___ Sarah’s mother can donate blood to people with blood types A+, AB-, or A-.
______ Sarah’s blood type is A-.
______ Sarah can receive blood from an AB+ individual.
A-
O+
___X___ Sarah’s father must be heterozygous for Rh factor (Rr).
______ Sarah’s mother’s blood type must be IAIA.
O+
___X___ Sarah has the Rh factor genotype rr.
Sarah
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Biol 200, Autumn 2014
Final Exam
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7. (15 pts) You design primers to a region of human DNA so that PCR should produce a 900 base pair
fragment. In order to test your primers, you run two identical PCR experiments except one has an
annealing temperature of 50°C (sample A) and the other has an annealing temperature of 60°C
(sample B). After 25 cycles of PCR, you run gel electrophoresis - your results are in the gel below.
Marker
a. (3) Which of the following could explain
the different results in samples A and B?
(Put an 'X' in blank of all correct answers)
A
B
C
bp
1000
______ The original DNA was taken from
a person who is a heterozygote.
800
600
______ The lower temperature caused the primers
to break apart into individual nucleotides.
____X__ The lower temperature allowed for primers
to bind to sequences that were not completely complementary.
Draw in your
answer for 'c'
______ There were more copies of the template DNA in sample A.
b. (3)You decide that you need to make more of the amplified fragment. Which of the following could
help you increase the total fragment number in a new reaction? ('X' in blank for all correct answers)
______ Add a third primer
______ Use 95°C instead of 90°C for the melting temperature
___X___ Increase the number of cycles
___X___ Add more copies of primer
c. (2) Suppose you succeeded in increasing the yield of fragments compared to sample B. Draw in
the results on the gel in lane "C".
d. (3) On a different day, you realize you forgot to add one of the primers to the tube. You stop the
PCR after cycle 13, add the second primer and then let the PCR finish (25 cycles total). What is the
expected result compared to "normal" PCR? (Put an 'X' in the blank for the BEST answer)
______ There will be amplification but the fragment yield will be about half the amount.
___X___ There will be amplification but the fragment yield will be dramatically lower.
______ There will be amplification but the fragment size will be shorter than expected.
______ There will not be amplification because both primers are needed at the beginning.
e. (2) Assuming that the primers you designed are 30 nucleotides long, how many
nucleotides will be added by Taq to complete the desired fragment? 870 nt
f. (2) During PCR, what takes the place of
topoisomerase (required for DNA replication in vivo)? heat
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Biol 200, Autumn 2014
Final Exam
*****KEY*****
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8. (10 pts) "Lactose intolerance" is generally seen in certain populations of people from roughly age 3
years and older. It is the inability to digest lactose. "Graph 1" at the bottom of the page shows
enzyme concentration in the small intestine as a function of age. The bottom right graph shows
enzyme activity as a function of temperature (enzyme for this graph was isolated at age 2 from both
populations).
a. (2) Which of the following describe the reaction catalyzed by the enzyme that digests lactose?
(Circle ALL correct answers)
exergonic
anabolic
ΔG > 0
requires ATP
spontaneous
b. (4) Is lactose intolerance likely caused by a change in the enzyme's protein structure? Explain in no
more than 2 sentences, using the data shown below.
Since the enzyme activity is identical between the two populations, it is unlikely that lactose
intolerance is a result of changes in protein structure.
c. (4) Imagine the gene for the enzyme has the following structure. (E=enhancer, P=promoter,
T=terminator)
5'
E
P
Exon1
Intron1
Exon2
Intron2
Exon3
T
3'
3'
5'
1
2
3
Which site (1, 2, or 3) is most likely the site of the mutation that causes lactose intolerance? Explain
your choice in no more than 2 sentences.
Graph 1 suggests that a change in enzyme production occurs at age 3 in "lactose intolerant"
individuals. This would most likely be due to a change in enhancer sequence (mutation 1), where
regulation of transcription of this gene is different in the two populations due to different
transcription factors expressed after age 3 .
Graph 1:
"lactose
tolerant"
high
Enzyme
concentration
"lactose
intolerant"
low
0
1
3
5
…
age (in years)
25
Graph 2:
"lactose
tolerant"
high
"lactose
intolerant"
Enzyme
activity
low
0
7
37 (body)
temperature (°C)
65