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Name___________________________ Lecture A
Version A
Final Exam
Bio 93 Fall 2011
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F ’11 Bio 93 Lecture A Multiple Choice Version A 1 Name___________________________ There are 35 multiple choice questions. There is one best answer for each question.
Question 1 is worth 0 points. Questions 2 - 35 are worth 2 points each for a total of
68 points.
1. You have version A. Please bubble in “A” for question 1. (0 points)
2. Kari, a Bio Sci 93 TA works with a protein called Tuba. When levels of Tuba are
lowered in somatic cells, the MTOC cannot function normally. Reducing Tuba levels in
interphase cells is likely to affect
a. Microtubule organization
b. Actin fiber formation
c. Kinesin binding to its cargo
d. Spindle poles
e. Myosin binding
3. A group of cells is assayed for DNA content immediately following mitosis and is
found to have an average of 8 picograms of DNA per nucleus. How many picograms
would be found at the end of S and the end of G2?
a. 8; 8
b. 8; 16
c. 16; 8
d. 16; 16
e. 12; 16
4. Addition of a drug that blocks formation of microtubules will most directly affect
which of the following functions of a white blood cell?
a. ability to detect bacteria that are nearby
b. extension of psuedopodia
c. transport of vesicles from the golgi to the plasma membrane
d. transport of sodium ions across the membrane through the sodium potassium
pump
e. control of water flow across the membrane through aquaporin channels
5. A sexually reproducing plant has a diploid chromosome number of 10. What is the
minimum number of different gametes it can produce based on Mendel’s law of
independent assortment.
a. 10
b. 5
c. 100
d. 32
e. 16
F ’11 Bio 93 Lecture A Multiple Choice Version A 2 Name___________________________ 6. Mating of a female horse (mare) with a male donkey produces a mule. Horses have a
diploid chromosome number of 64 while donkeys have a diploid chromosome number of
62. Somatic cells from a male mule should contain:
a. 64 chromosomes
b. 62 chromosomes
c. 32 chromosomes
d. 31 chromosomes
e. 63 chromosomes
7. Kinetochore proteins attach the kinetochores on sister chromatids during cell division.
Where in a cell would you find a ribosome completing synthesis of a kinetochore
protein?
a. inside the nucleus
b. on the microtubule spindle fibers
c. on the rough ER
d. free in the cytoplasm
8. Why did the F1 offspring in Mendel's classic pea crosses always look like one of the
two parental varieties?
a. No genes interacted to produce the parental phenotype.
b. Each allele affected phenotypic expression.
c. The traits blended together during fertilization.
d. One phenotype was completely dominant over another.
e. Different genes interacted to produce the parental phenotype.
9. When two plants are crossed, they produce offspring with a 3:1 ratio for a particular
trait. What does this suggest?
a. that the parents were true-breeding for epistatic traits
b. that the trait shows incomplete dominance
c. that a blending of traits has occurred
d. that the parents were both heterozygous for a single trait
e. that each offspring has the same alleles for each of two traits
10. Marfan syndrome in humans is caused by an abnormality in fibrillin, a connective
tissue protein. Patients are usually very tall and thin, with long spindly fingers, curvature
of the spine, weakened arterial walls, and ocular problems, such as lens dislocation.
Which of the following statements about Marfan syndrome is definitely true?
a. It is recessive.
b. It is dominant.
c. It has a late age of onset (> 60).
d. It is pleiotropic.
e. It is epistatic.
F ’11 Bio 93 Lecture A Multiple Choice Version A 3 Name___________________________ 11. In Drosophila, the mutations wingless (wg) and vestigial (vg) are two different genes
that map to the second chromosome and both result in wings that are smaller than
wildtype (+). If a homozygous wingless mutant fly is mated to a homozygous vestigial
mutant, which of the following offspring would you expect?
a. all +wg +vg heterozygotes
b. 1/2 wingless and 1/2 vestigial flies
c. all homozygous + flies
d. 3/4 wingless to 1/4 vestigial ratio
e. 1/2 wingless and vestigial to 1/2 normal
12. A woman who has blood type A has a daughter who is type O and a son who is type
B. Which of the following is a possible partial genotype for the son?
a. IB IB
b. IB IA
c. ii
d. IB i
e. IA IA
13. Red-green color blindness is a sex-linked recessive trait in humans. Two people with
normal color vision have a color-blind son. What are the genotypes of the parents?
a. Xr Xr and Xr Y and X
b. Xr Xr and XR Y
c. XR XR and Xr Y
d. XR XR and XR Y
e. XR Xr and XR Y
14. One possible result of chromosomal breakage is for a fragment to join a
nonhomologous chromosome. What is this alteration called?
a. deletion
b. transversion
c. inversion
d. translocation
e. duplication
F ’11 Bio 93 Lecture A Multiple Choice Version A 4 Name___________________________ 15. Jen, a Bio93 TA, studies the effects of Chlamydia trachomatis (a bacterium) on host
cells. In order to identify changes in host cell proteins, she needs to isolate proteins from
the other components of the cell. While processing infected cells, she uses an enzyme
called benzonase that hydrolyzes phosphodiester bonds. Which statement correctly
identifies a likely effect of benzonase treatment?
a.
b.
c.
d.
e.
Phospholipids in the cell membranes break down
Strands of DNA become single-stranded
Sugars are degraded
DNA and RNA is cut into shorter pieces
Short peptides are produced
16. You are provided with an actively dividing culture of E. coli bacteria to which
radioactive thymine has been added. What would happen if a cell replicates once in the
presence of this radioactive base?
a. One of the daughter cells, but not the other, would have radioactive DNA.
b. Neither of the two daughter cells would be radioactive.
c. All four bases of the DNA would be radioactive.
d. Radioactive thymine would pair with nonradioactive guanine.
e. DNA in both daughter cells would be radioactive.
17. As part of an experiment, a graduate student injects an mRNA molecule into the
cytoplasm of a eukaryotic cell after she has removed its 5' cap and poly-A tail. Which of
the following would you expect her to find?
a. The mRNA could not exit the nucleus to be translated.
b. The cell recognizes the absence of the tail and polyadenylates the mRNA.
c. The molecule is digested by restriction enzymes in the nucleus.
d. The molecule is digested by exonucleases since it is no longer protected at the 5'
or 3’ end.
e. The molecule attaches to a ribosome and is translated, but more slowly.
F ’11 Bio 93 Lecture A Multiple Choice Version A 5 Name___________________________ 5’ UTR – E 1 - I1 – E2 – I2 – E3 – I3 – E4 –UTR 3’
18. The figure represents a eukaryotic pre-mRNA. E1-4 are exons, I1-4 are introns.
Which components of the pre-mRNA will also be found in the mature mRNA in the
cytosol?
a. 5' UTR I1 I2 I3 UTR 3'
b. 5' E1 E2 E3 E4 3'
c. 5' UTR E1 E2 E3 E4 UTR 3'
d. 5' I1 I2 I3 3'
19. A point mutation in DNA could affect a protein's activity because
a. It might result in a chromosomal translocation.
b. It might exchange one stop codon for another stop codon.
c. It might exchange one serine codon for a different serine codon.
d. It might substitute an amino acid necessary for function.
e. It might substitute the N-terminus of the polypeptide for the C-terminus.
20. Your Bio93 TA Lauren studies a transcription factor called Ovol2 that is required for
normal mouse mammary gland development. Ovol2 is a single gene locus, yet there are
three distinct Ovol2 variants expressed at the protein level. Which of the following best
explains this phenomenon?
a. Alternative splicing of Ovol2 mRNA
b. Alteration of the Ovol2 transcript by microRNAs
c. Frameshift mutations in the Ovol2 gene sequence
d. The Ovol2 protein is recognized and degraded by the proteasome
e. Exons are not spliced out of the Ovol2 transcript
21. Which of the following describes the function of an enzyme known as Dicer?
a. It degrades single-stranded DNA.
b. It degrades single-stranded mRNA.
c. It degrades mRNA lacking a poly-A tail.
d. It trims small double-stranded RNAs.
e. It removes non-coding segments from immature mRNA.
F ’11 Bio 93 Lecture A Multiple Choice Version A 6 Name___________________________ 22. In eukaryotes, general transcription factors
a. are required for the expression of specific protein-encoding genes.
b. bind to other proteins or to a sequence element within the promoter called the
TATA box.
c. inhibit RNA polymerase binding to the promoter and begin transcribing.
d. usually lead to a high level of transcription even without additional specific
transcription factors.
e. bind to sequences just after the start site of transcription.
23. Which of the following modifications is least likely to alter the rate at which a DNA
fragment moves through a gel during electrophoresis?
a. altering the nucleotide sequence of the DNA fragment
b. digesting the DNA fragment with a restriction enzyme
c. increasing the length of the DNA fragment
d. decreasing the length of the DNA fragment
e. neutralizing the negative charges within the DNA fragment
24. Which of the following tools of recombinant DNA technology is incorrectly paired
with its use?
a. restriction enzyme <----> analysis of RFLPs
b. DNA ligase <----> cutting DNA, creating sticky ends of restriction fragments
c. DNA polymerase <----> polymerase chain reaction to amplify sections of DNA
d. RNA polymerase <----> production of RNA from DNA
e. electrophoresis <----> separation of DNA fragments
25. If a female Drosophila is homozygous for a mutation in a maternal effect gene,
a. she will not develop past the early embryonic stage.
b. all of her offspring will show the mutant phenotype, regardless of their genotype.
c. only her male offspring will show the mutant phenotype.
d. her offspring will show the mutant phenotype only if they are also homozygous
for the mutation.
e. only her female offspring will show the mutant phenotype.
26. Mutations in which of the following genes are most commonly associated with
transformations in the identity of entire body parts?
a. morphogens
b. segmentation genes
c. egg-polarity genes
d. homeotic genes
e. inducers
F ’11 Bio 93 Lecture A Multiple Choice Version A 7 Name___________________________ 27. During fertilization, the acrosomal contents
a. block polyspermy.
b. help propel more sperm toward the egg.
c. digest the protective jelly coat on the surface of the egg.
d. nourish the mitochondria of the sperm.
e. trigger the completion of meiosis by the sperm.
28. A human blastomere is
a. an embryonic cell that is much smaller than the ovum.
b. an embryonic structure that includes a fluid-filled cavity.
c. that part of the acrosome that opens the egg's membrane.
d. a component of the zona pellucida.
e. a cell that contains a (degenerating) second polar body.
29. Your TA Lauren studies a transcription factor called Ovol2 that is involved in
regulation of gene expression during mouse embryogenesis. Mutants lacking the Ovol2
gene display an open cranial neural tube, which is normally closed in a wildtype mouse.
Which of the following might explain this feature of Ovol2 mutants?
a. Ovol2 is an inhibitor of bicoid protein
b. Mutant embryos do not contain maternal effect genes
c. Ovol2 is required for migration of ectoderm cells
d. Mutant embryos develop two anterior axes
e. Ovol2 blocks notochord formation
30. Bekah, your Bio93 TA, studies the early development of Xenopus (frog). In a classic
experiment using Xenopus embryos, researchers found that cells from the animal pole of
the blastula (animal cap cells) formed epidermal cells when cultured in a dish. However,
when the animal cap cells were cultured in contact with vegetal pole cells, they also
formed muscle cells. What is the most likely conclusion?
a. the vegetal cells provide an inductive signal that cause the formation of ectoderm
b. vegetal cells inhibited the specification of mesoderm
c. the vegetal cells provide an inductive signal that caused the formation of
mesoderm
d. the animal cap cells are differentiated and can only become one tissue type
e. the vegetal cells provide an inductive signal that cause the formation of endoderm
F ’11 Bio 93 Lecture A Multiple Choice Version A 8 Name___________________________ 31. In the human knee-jerk reflex, as the calf is raised from the vertical toward the
horizontal, the muscles of the quadriceps (flexors on the ventral (bottom) side of the
thighs) and the muscles of the hamstring (extensors on the dorsal (top) side of the thighs)
are
a. both excited and contracting.
b. both inhibited and relaxed.
c. excited and inhibited, respectively.
d. inhibited and excited, respectively.
e. both responding to signals from the brain
32. Channelrhodopsin-2 (ChR2) is a light-gated sodium ion channel that responds to
intense blue light by opening and allowing Na+ to pass. ChR2 has been expressed in
neurons of different animals and is used as a tool for remote control of neurons, neural
circuits and behavior. If a neuron that is expressing ChR2 is exposed to intense blue light,
what is the first thing that will happen?
a. The neuron depolarizes and fires action potentials.
b. The extracellular K+ concentration will increase
c. The Na+K+ pumps will stop pumping
d. The membrane potential will be more negative
e. The membrane potential will remain at -70mv
33. Neural transmission across a mammalian synaptic gap is accomplished by
a. the movement of sodium and potassium ions from the presynaptic neuron into the
postsynaptic neuron.
b. impulses traveling as electrical currents across the gap.
c. impulses causing the release of a chemical signal that diffuses across the gap.
d. impulses ricocheting back and forth across the gap.
e. the movement of calcium ions from the presynaptic into the postsynaptic neuron.
34. Assume that a single IPSP has a negative magnitude of -0.5 mV at the axon hillock,
and that a single EPSP has a positive magnitude of +0.5 mV. For a neuron with an initial
membrane potential of -70 mV, the net effect of the simultaneous arrival of six IPSPs and
two EPSPs would be to move the membrane potential to
a. -72 mV.
b. -80 mV.
c. -70 mV.
d. -60 mV.
e. -68 mV.
35. Which of the following is not true of a codon?
a. It consists of three nucleotides.
b. It may code for the same amino acid as another codon.
c. It never codes for more than one amino acid.
d. It extends from one end of a tRNA molecule.
e. It is the basic unit of the genetic code
F ’11 Bio 93 Lecture A Multiple Choice Version A 9 Name___________________________ Fall 2011 Bio 93 Final - Short Answer Version X
Instructions: 25 points total. The answers to the following questions should be
completed in the space provided. Spell carefully. Make sure to put your name on the
top of these pages.
1. Glutamate is an amino acid that serves as the primary excitatory neurotransmitter in
the mammalian brain. The structure of Glutamate is shown below. Refer to it to answer
the following questions:
A) (2 points) How many carbon atoms are present in Glutamate? __________
B) (2 points) Which functional group is present in Glutamate’s R-Group? __________
C) (2 points) On the diagram, put a circle around the alpha-carbon
2. (2 points) What product of lactic acid fermentation allows continued production of
ATP in the absence of oxygen? __________________
F ’11 Bio 93 Lecture A Multiple Choice Version A 10 Name___________________________ 3. Edward is a graduate student researcher who also happens to be a vampire. His
personal life is a mess because of his relationship with Bella, another grad student who is
cheating on him with Jacob, a werewolf. During an early morning twilight, Edward
discovers an anti-werewolf gene that encodes a polypeptide toxin that permanently
changes werewolves into chihuahuas. In order to generate enough of the toxin to load
into a tranquilizer dart, Edward wants to construct a plasmid that would allow him to
mass produce the toxin using E. coli. You are sick and tired of hearing about the entire
situation, so you decide to help Edward with the production and purification of the toxin.
a) (2 points) The plasmid containing the anti-werewolf gene will be used to transform the
bacteria. You have media containing the antibiotic tetracycline. What should the plasmid
contain that will allow you to select only bacteria that have taken up the plasmid DNA?
b) (2 points) What kind of protein will you use to cleave the plasmid DNA?
c) (2 points) What type of bonds initially hold the cut plasmid DNA and the insert DNA
together?
d) (2 points) What enzyme will you need to covalently join the DNA fragment coding for
the anti-werewolf protein and the vector?
F ’11 Bio 93 Lecture A Multiple Choice Version A 11 Name___________________________ e) You and Edward successfully transform bacteria with your plasmid, however now you
must identify which E. coli colonies only contain the plasmid of interest. You isolate the
plasmids from individual colonies and fully digest them with the restriction enzymes
EcoRI and HindIII. Unfortunately, you knocked over a lab rack, and mixed up the antiwerewolf-transformed bacteria plates with another set of bacteria plates. To find the
correct plasmids, Edward patiently isolated plasmids from five different colonies,
digested them with EcoRI and HindIII, and got the following results. The correct antiwerewolf plasmid is shown on the left:
a. (2 points) Why can Lane E be excluded from being the correct plasmid?
b. (1 point) DNA from the correct plasmid is shown in Lane D. Why are only three bands
visible?
F ’11 Bio 93 Lecture A Multiple Choice Version A 12 Name___________________________ 4. In 1961 the biochemists Nirenberg and Khorana made synthetic mRNA to try to
understand the genetic code. When they produced mRNA containing only uracil
nucleotides, it coded for one type of amino acid, phenylalanine. When mRNA was
produced with alternating uracil and guanine nucleotides, two types of amino acid
were coded for, valine and cysteine. Alternating U’s and C’s produced Serine and
Leucine
Nucleotide sequence in mRNA
UUUUUUUUUUUUUUUUUUU
UGUGUGUGUGUGUGUGUG
UCUCUCUCUCUCUCUCUCU
Amino acids coded for
Phenylalanine
Valine and Cysteine
Serine and Leucine
a) (2 points) For the amino acid phenylalanine what is the tRNA anti-codon sequence?
Make sure to indicate the 5’ and 3’
________________
b) (2 points) What are the potential mRNA codons for Valine predicted by this
experiment. Make sure to indicate the 5’ and 3’?
___________________________
c) (2 points) What are the potential mRNA codons for Leucine? Make sure to indicate the
5’ and 3’?
___________________________
F ’11 Bio 93 Lecture A Multiple Choice Version A 13