GEN EXAM 4 QUIZZES Flashcards
(132 cards)
1
Q
A gene is inducible and under negative control. Which of the following pairs will allow expression of this gene?
A. activator + inhibitor
B. activator + repressor
C. repressor + inducer
D. repressor + corepressor
A
C. repressor + inducer
2
Q
Riboswitches have been shown to affect regulation of ______.
A. transcription and translation
B. only RNA splicing
C. only transcription
D. only translation
A
A. transcription and translation
3
Q
Which of the following is found in an operon?
A. promoter
B. terminator
C. two or more genes
D. operator
E. All of the answers are correct.
A
E. All of the answers are correct.
4
Q
A mutation in the lacI gene prevents the gene product from binding allolactose. What will the expression level of the operon be in the absence of lactose?
A. No transcription
B. Transcription will occur only in the presence of glucose
C. Positive regulation
D. Constitutively active
A
A. No transcription
5
Q
A deletion in an operon removes the terminator. How will that affect the transcript that is produced from the operon?
A. The transcript will be produced and normal in length
B. The transcript will be produced, but will contain a deletion
C. The transcript will be produced, but longer than normal
D. The transcript will not be produced
E. The transcript will be produced, but shorter than normal
A
C. The transcript will be produced, but longer than normal
6
Q
What is the gene responsible for attenuation in the trp operon?
A. trpR
B. trpD
C. trpL
D. trpC
A
C. trpL
7
Q
If the Trp codons in the trpL gene were mutated to encode another amino acid, what would the result be?
A. The trp operon would only be transcribed when tryptophan in the cell was high.
B. The trp operon would never be transcribed.
C. The trp operon would always be transcribed.
D. The trp operon would only be transcribed when tryptophan in the cell was low.
A
B. The trp operon would never be transcribed.
8
Q
In a particular E. coli strain, a mutation in the thiMD operon results in improper formation of the stem loop secondary structure making it impossible to bind TPP. There are two enzymes encoded by the thiMD operon. How many of the enzymes encoded in the thiMD operon are translated?
A. One
B. Zero
C. Two
D. Three
A
C. Two
9
Q
The regulation of protein function, not gene expression is called ______ regulation.
A. translational
B. transcriptional
C. posttranslational
D. posttranscriptional
A
C. posttranslational
10
Q
Antisense RNA does which of the following?
A. binds to a complementary RNA and prevents its translation
B. occupies the A and P sites of the ribosome
C. inhibits the formation of the open complex in transcription
D. prevents the correct folding of a newly formed peptide
A
A. binds to a complementary RNA and prevents its translation
11
Q
If a bacterium is placed in an environment that contains both glucose and lactose, the regulation of the lac operon will allow which nutrient to be processed first?
A. glucose
B. lactose
C. Both will be processed equally.
D. Neither will be processed in this environment.
A
A. glucose
12
Q
In Jacob, Monod, and Pardee’s experiment, how many functional copies of lacI were there in the merozygote?
A. 2
B. 1
C. 3
D. 0
A
B. 1
13
Q
Regulation of gene expression may occur at which of the following level?
A. transcription
B. translation
C. posttranslation
D. All of the answers are correct.
A
D. All of the answers are correct.
14
Q
What stem-loop conformations favor attenuation in the trp operon?
A. 1-2 and 2-3
B. 2-3
C. 1-2
D. 3-4
A
D. 3-4
15
Q
Allosteric regulation is accomplished by
A. a small molecule that fits into a site on the enzyme that is not the active site.
B. a small molecule that covalently modifies a site on the enzyme that is not the active site.
C. a large protein that blocks an enzyme’s active site.
D. a small molecule that fits into an enzyme’s active site.
A
A. a small molecule that fits into a site on the enzyme that is not the active site.
16
Q
In the Jacob Monod merozygote experiment, what was indicated by the presence of a yellow color when b-ONPG was added?
A. The lac operon was completely turned off.
B. The researcher added too much b-ONPG.
C. Beta-galactosidase was present.
D. Expression of the lac operon is constitutive whether lacI is functional or not.
A
C. Beta-galactosidase was present.
17
Q
A deletion in an operon removes the promoter. How will that affect the transcript that is produced from the operon?
A. The transcript will not be produced
B. The transcript will be produced, but shorter than normal
C. The transcript will produced, but will contain a deletion
D. The transcript will be produced, but longer than normal
E. The transcript will be produced and normal in length
A
A. The transcript will not be produced
18
Q
Translational regulatory proteins recognize specific areas of what molecule?
A. tRNA
B. Ribosome
C. rRNA
D. mRNA
E. None of the answers are correct.
A
D. mRNA
19
Q
How many promoters are in an operon?
A. 3
B. 1
C. It depends on how many genes there are in the operon
D. 2
A
B. 1
20
Q
In Jacob, Monod, and Pardee’s experiment, what would have been the conclusion if all four tubes produced a yellow color when β-ONPG was added?
A. LacI provides the binding site for the repressor
B. Expression of the lac operon is constitutive whether lacI is functional or not
C. LacI encodes a diffusible repressor
D. The researcher added too much β-ONPG
A
B. Expression of the lac operon is constitutive whether lacI is functional or not
21
Q
Which of the following is not an example of translational regulation in prokaryotes?
A. Binding of antisense RNA to mRNA
B. Altering the structure of the mRNA
C. Phosphorylation of an enzyme
D. Sterically blocking the ribosome
A
C. Phosphorylation of an enzyme
22
Q
Which DNA repair process utilizes MutL, MutH, and MutS proteins in E. coli?
A. nucleotide excision repair
B. direct repair
C. nonhomologous end joining (NHEJ)
D. base excision repair
E. homologous recombination repair
F. mismatch repair
A
F. mismatch repair
23
Q
Which process is used to replicate DNA that contains distortions due to unrepaired DNA damage?
A. Translesion synthesis
B. Nonhomologous end joining
C. Nucleotide excision repair
D. Homologous recombination repair
A
A. Translesion synthesis
24
Q
Which types of mutations are least likely to be subjected to natural selection?
A. Insertion
B. Nonsense
C. Missense
D. Silent
A
D. Silent
25
Beechdrops is a parasitic plant that cannot perform photosynthesis but relies on its host the Beech tree. However, beechdrops still retains many if not all of the genes for photosynthesis. Snapdragons and gladiolas are common garden flowers that rely on their ability to perform photosynthesis. If you were to compare the gene sequences for these three plants for ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) a protein necessary for photosynthesis what would you predict?
A. The differences between gladiolas and snapdragons would most likely be missense mutations while those in beechdrops may be silent or missense
B. The differences between gladiolas and snapdragons would most likely be silent mutations while those in beechdrops may be silent or missense
C. Since these three plants are not highly related the sequences for RuBisCO would be very different between them
D. The differences between gladiolas and snapdragons would most likely be in the second nucleotide of codons while beechdrops would have a higher number of mutations in the third nucleotide of the different codons
B. The differences between gladiolas and snapdragons would most likely be silent mutations while those in beechdrops may be silent or missense
26
How does position effect influence gene expression?
A. The movement of the genetic material on the chromosome by inversions or translocations may place a coding sequence near a new regulatory region, thus activating the expression of the gene.
B. The movement of the gene may place it into a region that is highly condensed.
C. The movement of a gene may remove it from its normal promoter, thus silencing the gene.
D. All of the answers are correct.
D. All of the answers are correct.
27
Which of the following is correct regarding the rate of mutation?
A. Mutation rates are consistent across species.
B. Mutation rates are constant.
C. Rates of mutation per cell generation typically range from 10^−5 to 10^−9.
D. Mutation rates are not influenced by environmental conditions.
C. Rates of mutation per cell generation typically range from 10^−5 to 10^−9.
28
After screening a colony of bacteria for a given gene, you discover 100 mutant colonies out of 3 million total colonies. What is the mutation rate for this gene in the population?
A. 1.0 x 10^-5
B. 1.0 x 10^5
C. 3.3 x 10^-5
D. 3.0 x 10^5
C. 3.3 x 10-5
29
What would be a set of anticipated results from a "Lederberg" experiment?
A. Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 15
B. Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 1500
C. Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 0
D. Total number of colonies on a plate: 500 Total number of resistant colonies on replica plate with T1: 1500
A. Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 15
30
Which of the following is not an example of a cause of a spontaneous mutation?
A. aberrant recombination
B. transposable elements
C. DNA replication errors
D. tautomeric shifts
E. UV light
E. UV light
31
The conversion of cytosine to uracil in DNA is an example of _____.
A. depurination
B. tautomeric shifts
C. deamination
D. None of the answers are correct.
C. deamination
32
Four cancer patients are treated with an experimental drug. Patients #2 and #4 have an extremely serious adverse reaction to the drug. Another patient (#5) requests to enter the trial and you do not wish to treat this patient if there is any indication that the new patient will have the same side effect. The haplotypes for the region where the allele that controls this sensitivity has been mapped and the haplotypes for this region for these patients are given below. Should you enter patient #5 into the trial?
1: 1A 2B 3C 4B/1A 2B 3A 4C
2: 1A 2C 3B 4B/1B 2A 3B 4A
3: 1B 2A 3A 4B/1C 2B 3A 4A
4: 1B 2C 3B 4B/1A 2B 3A 4C
5: 1A 2B 3A 4C/1B 2A 3B 4A
A. Yes, #5 shares no haplotype combinations with #2 and #4.
B. Yes, since there are no shared haplotypes between #2 and #4 these haplotypes are not correlating with the drug sensitivity.
C. No, # 5 shares the 1A haplotype with #2 and #4.
D. No, # 5 shares the 3B haplotype with
A. Yes, #5 shares no haplotype combinations with #2 and #4.
33
You are working in a lab where you are studying a disease that is known to be caused by a single nucleotide change, although the effect this change ultimately has on the protein's structure/function is unknown. You have DNA samples from multiple patients that you suspect of having this disease. What is the most efficient way to test the samples for the relevant mutation?
A. Karyotyping
B. Amniocentesis
C. Western blotting
D. DNA sequencing
D. DNA sequencing
34
Which technique can be used at the earliest stage in a pregnancy to provide a sample for fetal genetic testing?
A. amniocentesis
B. chorionic villus sampling
C. Both chorionic villus sampling and amniocentesis are performed at the same stage in a pregnancy.
B. chorionic villus sampling
35
For a single-gene disorder, the concordance among monozygotic twins should be
A. 75%.
B. 50%.
C. 0%.
D. 100%.
E. 25%.
D. 100%.
36
In the analysis of a family, you notice that males are more likely to contract a certain disease, and the daughters of affected males produce 50% of their sons affected with the disease. This disease is displaying which of the following patterns of inheritance?
A. X-linked recessive
B. autosomal recessive
C. autosomal dominant
D. None of these choices are correct.
A. X-linked recessive
37
A gene that promotes the development of cancer when it sustains a gain-of-function mutation is called a
A. proto-oncogene
B. tumor suppressor gene.
C. housekeeping gene.
D. caretaker gene.
A. proto-oncogene
38
The term that indicates that cancer has begun to migrate to other parts of the body is ______.
A. malignant
B. invasive
C. clonal
D. metastatic
E. benign
D. metastatic
39
An example of personalized medicine would be
A. performing an appendectomy on a patient with appendicitis.
B. treatment of diabetics with synthetic instead of natural insulin.
C. treatment of an infection based on the drug resistance of the bacterium.
D. determining the CYP2C9 alleles present to help set the patient's coumarin dose.
D. determining the CYP2C9 alleles present to help set the patient's coumarin dose.
40
Epigenetics may play a role in cancer by
A. directly resulting in gene deletions.
B. directly inducing inversion mutations.
C. causing translocations.
D. causing a change in gene expression patterns.
D. causing a change in gene expression patterns.
41
Caspases are active during which of the following?
A. viral integration
B. the normal cell cycle
C. apoptosis
D. DNA replication
C. apoptosis
42
What would be the result if the U-rich sequence after the fourth stem loop in the trp operon was replaced by a UG-rich sequence?
A. Attenuation would occur if tryptophan was high.
B. Attenuation would occur if tryptophan is low.
C. Attenuation would not occur if tryptophan was high.
D. None of the answers are correct.
C. Attenuation would not occur if tryptophan was high.
43
Enzymes involved in metabolism are most likely regulated via _____.
A. feedback inhibition
B. acetylation
C. methylation
D. None of the answers are correct.
A. feedback inhibition
44
Chromatin remodeling complexes alter nucleosomes, this occurs when
A) remodeling proteins bind to TFIID to promote or inhibit nucleosome formation.
B) complexes of ATP-dependent protein degrade histones and release the DNA from nucleosomes.
C) complexes of ATP-dependent proteins may reposition, evict, or change nucleosome composition.
D) remodeling proteins increase the supercoiling of the DNA, which can inhibit nucleosome formation.
C) complexes of ATP-dependent proteins may reposition, evict, or change nucleosome composition
45
In cancer cells, one allele of a tumor suppressor gene called p53 is frequently mutated so that the protein is inactive, not produced, or deleted. The other allele usually has a normal sequence and the promoter remains intact, but the gene is not expressed. Sequencing with sodium bisulfite modification of DNA can be used to detect which cytosines are methylated. If cancer cell DNA is sequenced, which of the following results would be expected?
A) There will be no differences in the methylation pattern of the promoter of p53 from a cancer cell and a normal cell
B) Cytosines in the coding region will have an increased methylation
C) Cytosines in or near the promoter region will be methylated
D) Cytosines in or near the promoter will not be methylated
C) Cytosines in or near the promoter region will be methylated
46
One difference between developmental and environmental epigenetic changes is that
A) developmental epigenetic control is a normal process that occurs in all offspring.
B) environmental epigenetic control is the result of developmental processes interacting with the environment.
C) the differences between the two lie in the mechanisms that each uses.
D) environmental epigenetic control is a normal process that occurs in all offspring.
A) developmental epigenetic control is a normal process that occurs in all offspring.
47
What is the difference between the trithorax (TrxG) and polycomb (PcG) complexes of proteins?
A) Methylation of H3 on lysine 27 can result in activation of transcription
B) TrxG complex proteins activate gene expression by methylating lysine 4 on H3, while PcG complex proteins repress gene expression by methylating lysine 27 on H3.
C) Methylation of lysine at position 4 on H3 results in silencing of gene expression
D) TrxG proteins methylate lysine 27 on histone H3 while PcG complexes methylate lysine 4 on H3
B) TrxG complex proteins activate gene expression by methylating lysine 4 on H3, while PcG complex proteins repress gene expression by methylating lysine 27 on H3.
48
The Avy allele of the Agouti gene involves the insertion of a transposable element upstream from the normal Agouti promoter. The transposable element carries a promoter that causes the overexpression of the Agouti gene. Mice carrying this allele tend to have coat colors that are more yellow than mice that don't have this transposable element. If pregnant female mice are fed a diet that contains chemicals that inhibit DNA methylation, how would you expect that this diet would affect the coat color of offspring carrying the Avy allele?
A) Their fur would be more yellow because the Agouti gene would tend to be over expressed.
B) Their fur would be less yellow (darker brown) because the Agouti gene would tend to be over expressed.
C) Their fur would be less yellow (darker brown) because the Agouti gene would tend to be under expressed.
D) Their fur would be more yellow because the Agouti gene would tend to be under
A) Their fur would be more yellow because the Agouti gene would tend to be over expressed.
49
Following mitosis, the two daughter cells usually have __________ pattern of facultative heterochromatin and __________ pattern of constitutive heterochromatin as was present in the mother cell.
A) a different; the same
B) the same; the same
C) a different; a different
D)the same; a different
B) the same; the same
50
Which of the following statements are correct?
A) Changes in gene expression based on environmental conditions are not considered normal while developmental changes are.
B) Environmental epigenetic gene regulation is typically reversible while developmental epigenetic gene regulation is typically not reversible.
C) Environmental epigenetic changes can vary due to the exposure of the organism to different environmental conditions, while those programmed during development are the result of stimuli generated by the organism itself.
D)Environmental epigenetic gene regulation only occurs in reptiles and insects, while developmental epigenetic regulation occurs in all animals.
C) Environmental epigenetic changes can vary due to the exposure of the organism to different environmental conditions, while those programmed during development are the result of stimuli generated by the organism itself.
51
Where is the IRE located in the regulation of ferritin translation?
A) 5′ end of mRNA
B) 5′ end of DNA
C) 3′ end of mRNA
D) 3′ end of DNA
A) 5′ end of mRNA
52
Regulatory transcription factors may influence gene expression in which of the following ways?
A) by directly interacting with TFIII to inhibit its binding to the core promoter
B) influencing the ability of the RNA polymerase to perform elongation
C) directly recruiting RNA polymerase to the promoter without interacting with any other proteins
D) recruiting proteins to the promoter that enhance chromatin compaction
D) recruiting proteins to the promoter that enhance chromatin compaction
53
Which of the following is incorrect regarding the glucocorticoid hormones?
A) The homodimer interacts with GRE, activating transcription.
B) After interacting with the receptor, they release HSP90.
C) The receptors form a homodimer that travels to the nucleus.
D) They interact with receptors located in the plasma membrane of the cell.
D)They interact with receptors located in the plasma membrane of the cell.
54
Acetylation of histones results in
A. formation of a closed chromatin structure.
B. termination of transcription.
C. removal of histones from the histone octamer.
D. formation of an open chromatin structure.
D. formation of an open chromatin structure.
55
Genomic imprinting is a result of
A. nucleosome location.
B. histone activation.
C. DNA methylation.
D. serine to leucine changes in the genetic code.
C. DNA methylation.
56
What genes appear to be controlled by the Xic?
A. Xist
B. Xist and Tsix
C. TsiX
D. Xic
B. Xist and Tsix
57
What gene(s) is/are encoded in the Xic?
A. Xce
B. Xist
C. Tsix
D. Both the Tsix and Xist are genes are in the Xic region
D. Both the Tsix and Xist are genes are in the Xic region
58
The Avy allele of the Agouti gene involves the insertion of a transposable element upstream from the normal Agouti promoter. The transposable element carries a promoter that causes the overexpression of the Agouti gene. Mice carrying this allele tend to have coat colors that are more yellow than mice that don’t have this transposable element. If pregnant female mice are fed a diet that contains chemicals that increase DNA methylation, how would you expect that this diet would affect the coat color of offspring carrying the Avy allele?
A. Their fur would be less yellow (darker brown) because the Agouti gene would tend to be under expressed.
B. Their fur would be more yellow because the Agouti gene would tend to be over expressed.
C. Their fur would be more yellow because the Agouti gene would tend to be under expressed.
D. Their fur would be less yellow (darker brown) because the Agouti gene would tend to be over expressed.
A. Their fur would be less yellow (darker brown) because the Agouti gene would tend to be under expressed.
59
Regulatory transcription factors may be regulated by
A. lipid modifications.
B. phosphorylation.
C. binding of carbohydrates.
D. sulfation.
B. phosphorylation.
60
Which DNA sequence would also work in place of the following bi-directional enhancer?
5' GTTC 3'
3' CAAG 5'
A. 5' CTTG 3'
3' GAAC 5'
B. 5' GAAC 3'
3' CTTG 5'
C. 5' CAAG 3'
3' GTTC 5'
D. 5' CTTC 3'
3' GAAG 5'
B. 5' GAAC 3'
3' CTTG 5'
61
CAP affects which operon(s)?
A. the lac operon
B. the trp operon
C. both the lac and the trp operon
D. neither the lac nor the trp operon
A. the lac operon
62
What are histone variants?
A. histone proteins that have slightly different amino acid sequences but are found in nucleosomes throughout the chromosomes
B. histone proteins that have been modified by acetylation and phosphorylation
C. histone proteins that have been modified by acetylation
D. histone proteins that have slightly different amino acid sequences and have specialized functions
D. histone proteins that have slightly different amino acid sequences and have specialized functions
63
What is the molecular mechanism for imprinting a gene?
A. Nitration
B. Phosphorylation
C. Acetylation
D. Methylation
D. Methylation
64
Expression of ______ would inhibit X-chromosome inactivation.
A. Xic
B. Xist
C. Tsix
D. All of the answers are correct.
E. None of the answers are correct.
C. Tsix
65
A queen bee is larger than the female worker bees in a hive. The queen develops functional ovaries that allow her to produce up to 2000 eggs a day. What determines which bees become queen bees?
A. The larvae raised on a diet of royal jelly
B. A single dominant allele of the Queen gene
C. The egg that hatches first
D. The larvae raised on a diet of pollen and nectar
A. The larvae raised on a diet of royal jelly
66
Regions of chromatin that are more compact are called __________; they are usually found __________ in the nucleus.
A. euchromatin; centrally
B. euchromatin; at the periphery
C. heterochromatin; centrally
D. heterochromatin; at the periphery
D. heterochromatin; at the periphery
67
What are some types of the molecular changes that underlie epigenetic gene regulation?
A. DNA methylation and depurination of cytosine residues
B. depurination and chromatin remodeling.
C. DNA methylation and chromatin remodeling
D. depurination of cytosine and thymidine residues
C. DNA methylation and chromatin remodeling
68
What is a major difference between the general and regulatory transcription factors?
A. General transcription factors act as heterodimers while regulatory transcription factors act as monomers.
B. General transcription factors only regulate the housekeeping genes while regulatory transcription factors control all of the other genes.
C. General transcription factors are essential for any transcription for all genes while regulatory transcription factors regulate transcription of specific genes.
D. General transcription factors regulate basal genes while regulatory transcription factors control all of the other genes.
C. General transcription factors are essential for any transcription for all genes while regulatory transcription factors regulate transcription of specific genes.
69
What process repairs damage from UV radiation?
A. direct repair
B. base excision repair
C. nonhomologous end joining (NHEJ)
D. homologous recombination repair
E. nucleotide excision repair
E. nucleotide excision repair
70
Which DNA repair process identifies daughter strands by methylation?
A. homologous recombination repair
B. mismatch repair
C. direct repair
D. nucleotide excision repair
E. nonhomologous end joining (NHEJ)
F. base excision repair
B. mismatch repair
71
A translocation that moves a gene from an area of euchromatin to heterochromatin would typically cause _____ in the expression of the gene.
A. no change
B. an increase
C. a reduction
C. a reduction
72
The results of the replica plating experiments by the Lederbergs supported which of the following theories?
A. random mutation theory
B. physiological adaptation theory
C. both theories
D. neither theory
A. random mutation theory
73
Most trinucleotide repeat expansion repeats involve expansion of which of the following?
A. GAA
B. any codon containing three of the same bases
C. ATG
D. CAG
D. CAG
74
A temporary change in the structure of a nitrogenous base is called ______.
A. depurination
B. a tautomeric shift
C. deamination
D. None of the answers are correct.
B. a tautomeric shift
75
What is the difference between genetic testing and genetic screening?
A. Genetic testing is concerned more with individuals and genetic screening is concerned with populations.
B. Genetic screening is concerned more with individuals and genetic testing is concerned with populations.
C. They use different tests and techniques to detect genetic mutations.
D. Genetic testing is concerned more with nonlethal syndromes and diseases, and genetic screening is concerned with lethal diseases and syndromes.
A. Genetic testing is concerned more with individuals and genetic screening is concerned with populations.
76
In the United States, most newborns undergo a test for primary congenital hypothyroidism, a condition where people are unable to produce enough thyroid hormone. On a nationwide basis, this is an example of __________.
A. genetic testing
B. preimplantation genetic diagnosis
C. amniocentesis
D. genetic screening
D. genetic screening
77
Which of the following would indicate that a disease has a genetic, rather than environmental, cause?
A. The disease is cured by taking an antibiotic.
B. The disease occurs as frequently between close relatives as it does in unrelated individuals.
C. The disease occurs at the same rate in individuals that are exposed to a similar environment.
D. The disease has a specific age of onset.
D. The disease has a specific age of onset.
78
How would a mutation that increases the rate of GTP hydrolysis by the Ras protein affect the EGF signaling pathway and how would it affect cell growth?
A. The signaling pathway would stay turned on and cell growth would be inhibited.
B. The signaling pathway would stay turned on and cell growth would be stimulated.
C. The signaling pathway would be turned off faster and cell growth would be inhibited.
D. The signaling pathway would be turned off faster and cell growth would be stimulated.
C. The signaling pathway would be turned off faster and cell growth would be inhibited.
79
What are the general ways that tumor suppressors and oncogenes act?
A. Tumor suppressors inhibit the cell cycle and oncogenes stimulate the cell cycle.
B. Oncogenes inhibit the cell cycle and tumor suppressors stimulate the cell cycle.
C. Both tumor suppressors and oncogenes stimulate the cell cycle.
D. Both tumor suppressors and oncogenes inhibit the cell cycle.
A. Tumor suppressors inhibit the cell cycle and oncogenes stimulate the cell cycle.
80
What kind of mutation would be expected both within oncogenes and tumor suppressor genes that would result in gain-of-function or loss-of-function, respectively?
A. Silent
B. Amplifications
C. Missense
D. Neutral
C. Missense
81
Genome wide association studies are used __________.
A. to identify single nucleotide polymorphisms that are near disease causing genes
B. to identify the mutation that causes a disease
C. to describe the number of alleles for a specific gene
D. to find the total variation that occurs in human genomes
A. to identify single nucleotide polymorphisms that are near disease causing genes
82
The process of _______ removes amniotic fluid from a pregnant mother to examine fetal cells for genetic problems.
A. chorionic villus sampling
B. in vitro fertilization
C. amniocentesis
D. preimplantation genetic diagnosis
C. amniocentesis
83
Gene X can exist as a normal allele and also as a dominant mutant allele that causes a disease. You purify protein X from a homozygous normal individual and also from an individual that is homozygous for the mutant allele. You have an assay to determine the function of protein X. When you assay 1 mg of the purified protein from a normal homozygote, the activity is 100%. When you mix together 0.5 mg of the normal protein and 0.5 mg of the mutant protein, the activity is 13%. Based on this experiment, what type of dominant mutant is this?
A. Dominant negative
B. Gain of function
C. Haploinsufficiency
D. Could be B and C
A. Dominant negative
84
The general function of the p53 protein could be described as
A. a negative regulator of cell division.
B. maintaining genome integrity
C. a positive regulator of cell division.
B. maintaining genome integrity
85
Mutations that change the configuration of a protein at a specific temperature are called ____ mutations.
A. deleterious
B. beneficial
C. conditional
D. neutral
C. conditional
86
Which of the following integrate into the double-helix of DNA, interfering with DNA replication?
A. acridine dyes
B. 5BU
C. nitrous acid
D. EMS
A. acridine dyes
87
You are a doctor tasked with diagnosing a patient that comes to you with mental impairment. Upon performing genetic tests, you find he has approximately 300 repeats of GCC in one of his genes. His father and grandfather had similar mental impairment but were never diagnosed with a condition prior to their death. His grandmother, mother, and sisters are unaffected. What disease do you predict that this patient has?
A. SBMA
B. FRAXA
C. HD
D. FRAXE
E. SCA1
D. FRAXE
88
If the individuals in the picture above had a child, that child could have which haplotype listed (assuming no crossing over)?
A. 1A2A3A4A; 1B2B3A4B
B. 1A2A3A4A; 1C2C3C4A
C. 1A2B3B4C; 1C2C3C4A
D. 1A2B3C4A; 1C2C3B4C
B. 1A2A3A4A; 1C2C3C4A
89
Which of the following is typically associated with an autosomal recessive pattern of inheritance?
A. an affected individual with one affected parent will have 50% of its offspring affected
B. an affected offspring has one or more affected parents
C. two affected heterozygous individuals will have 25% of their offspring unaffected
D. an affected offspring has two unaffected parents
D. an affected offspring has two unaffected parents
90
An oncogene form of Ras would have which of the following characteristics?
A. decreased GTPase activity
B. increased GTPase activity
C. decreased exchange of GDP for GTP
D. an increased number of copies in the cell
A. decreased GTPase activity
91
Tamoxifen is a medication used for treating cancer. Many women were found to have resistance to this drug, and research showed that women with a mutation in their CYP2D6 gene could not break down Tamoxifen. Therefore Tamoxifen was not a useful treatment for their cancer. Women can now be screened for this mutation, allowing clinicians to use a therapy that is effective for each woman. This type of treatment is an example of __________.
A. haplotype association studies
B. loss of heterozygosity
C. karyotyping
D. personalized medicine
D. personalized medicine
92
The term that refers to the linkage of alleles or molecular markers along a single chromosome is
A) loss of variation.
B) association group.
C) haplotype.
D) recombination group.
C) haplotype.
93
You are analyzing a human pedigree for a new disease and discover that the disease occurs with the same frequency in both sexes and that 25% of the children from two unaffected heterozygous parents have the disease. This disease is displaying ____ inheritance.
A) sex-linked dominant
B) autosomal recessive
C) sex-linked recessive
D) autosomal dominant
B) autosomal recessive
94
The term for the use of information about a person's genotype and other clinical data in order to select a medication is referred to as
A) minimalized drug therapy.
B) molecular profiling.
C) personalized medicine.
D) best medical practices.
C) personalized medicine.
95
What gene is most responsible for X-chromosome inactivation?
A) Xce
B) Xist
C) Xic
D) Tsix
B) Xist
96
Imagine all the histone H3 molecules in the cell have a mutation that changes their lysine-9 residue to an alanine. Assuming this cell could still live, what would be the result?
A) The ability of the cell to form euchromatin would be hindered.
B) The ability of the cell to imprint genes would be hindered.
C) The ability of the cell to form heterochromatin would be hindered.
D) There would little effect because lysine and alanine are similar amino acids.
C) The ability of the cell to form heterochromatin would be hindered.
97
Epigenetic inheritance may occur at which of the following stages?
A) Oogenesis
B) Spermatogenesis
C) Embryogenesis
D) All of the answers are correct.
D) All of the answers are correct.
98
What effect will a mutation in IRP that prevents it from binding to iron have on an individual?
A) Ferritin will not be made, so iron intake must be maximized.
B) There will be excess ferritin, so iron intake must be lowered.
C) Transferrin will not be made, so iron intake must be maximized.
D) There will be excess transferrin, so iron intake must be lowered.
D) There will be excess transferrin, so iron intake must be lowered.
99
What is an example of a suppressor mutation?
A) an intragenic mutation that restores protein structure
B) an intergenic mutation that increases the activity of a protein performing the same function as the mutated protein
C) an intergenic mutation that alters a transcription factor to activate the expression of a compensating protein
D) All of the answers are possible suppressor mutations.
D) All of the answers are possible suppressor mutations.
100
In the following sequence of DNA, the italicized base has been mutated. What type of mutation is this?
5' - G A T C T C C G A A T T - 3' original strand
5' - G A T C T C C C A A T T - 3' mutated strand
A) transition
B) transversion
C) neither
B) transversion
101
Which of the following is an example of a base analog?
A) EMS
B) 5BU
C) nitrogen mustards
D) nitrous acid
B) 5BU
102
Which environmental agent shown can induce mutations?
A. UV radiation
B. X-rays
C. gamma rays
D. All of the answers are correct.
D. All of the answers are correct.
103
Anticipation is associated with which of the following?
A. TRNE mutations
B. up-promoter mutations
C. intergenic suppressors
D. nonsense mutations
A. TRNE mutations
104
There is a spectrum of syndromes in humans known as Xeroderma pigmentosum. The individuals that have XD most commonly have mutations in their nucleotide excision DNA repair mechanisms that make them particularly susceptible to environmental mutagens such as UV light. Individuals have to be careful with how much sunlight they are exposed to since they have an extremely elevated chance for developing skin cancer. There have been several cell lines that have been established from XD patients that can be studied in tissue culture. In an experiment, several different cell lines of unknown origin were tested for their ability to undergo unscheduled DNA synthesis (UDS), an assay for DNA repair. In this essay, the amount of radioactive nucleotides that are incorporated into DNA after the cell sustains a mutagenic event are measured. The amount of radioactivity incorporated is measured by the number of counts per minute (CPM)
A. A
B. B
C. C
D. D
A. A
105
In the nucleotide excision repair system, which of the following proteins is responsible for recognizing a thymine dimer to be repaired?
A) UvrA/UvrB
B) UvrC
C) UvrD
D) None of the answers are correct.
A) UvrA/UvrB
106
The wild-type eye color of Drosophila is red. A single-base mutation occurs that produces a white eye color. Which of the following is correct regarding this mutation?
A) It is an example of a mutation that alters protein function.
B) Individuals with white eyes are called reversions.
C) It would be an example of a silent mutation.
D) All of the answers are correct.
A) It is an example of a mutation that alters protein function.
107
Translocations and inversions may cause which of the following?
A) TRNE
B) genome mutations
C) position effect
D) anticipation
C) position effect
108
Which DNA repair process often leads to deletion in chromosome sequence?
A. homologous recombination repair
B. nonhomologous end joining (NHEJ)
C. nucleotide excision repair
D. direct repair
E. mismatch repair
F. base excision repair
B. nonhomologous end joining (NHEJ)
109
If a point mutation increases the number of offspring an organism can produce, it would be called a _____ mutation.
A. deleterious
B. conditional
D. lethal
E. neutral
F. beneficial
F. beneficial
110
What are some of the steps in eukaryotic transcriptional control?
A. A transcriptional activator recruits general transcription factors and RNA polymerase II. Finally, as transcription elongation occurs, histone cores remain with the DNA.
B. A transcriptional repressor recruits nucleosome remodeling proteins that alter nucleosome positioning, modification, and composition. This allows for the formation of a closed chromatin complex, and binding of general transcription factors and RNA polymerase II. Histone cores remain on the gene as transcript elongation occurs.
C. A transcriptional activator recruits nucleosome remodeling proteins that alter nucleosome positioning, modification and composition. This allows for the formation of an open chromatin complex, and binding of general transcription factors and RNA polymerase II. Finally, as transcription elongation occurs, histone cores are evicted from the DNA to allow the RNA polymerase to transcribe the gene.
C. A transcriptional activator recruits nucleosome remodeling proteins that alter nucleosome positioning, modification and composition. This allows for the formation of an open chromatin complex, and binding of general transcription factors and RNA polymerase II. Finally, as transcription elongation occurs, histone cores are evicted from the DNA to allow the RNA polymerase to transcribe the gene.
111
Gene methylation can be detected through the use of restriction endonucleases. Usually these are used in pairs where one enzyme will digest only unmethylated DNA in its recognition sequence while the other is insensitive to methylation. Which of the following statements is correct?
A. The enzyme that is insensitive to methylation serves as a control to make sure the inability of the other enzyme to digest DNA is not due to a mutation.
B. This experimental design is able to identify the number of methylated C residues in a particular region of DNA.
C. The experimental design is flawed because there should be a third enzyme that would serve as a positive control
D. These are used in pairs because experiments have to be replicated and this one way of performing a replication of the experiment.
A. The enzyme that is insensitive to methylation serves as a control to make sure the inability of the other enzyme to digest DNA is not due to a mutation.
112
In humans, a recent study has shown that maternal anxiety during pregnancy can diminish the methylation of the ICR located between the H19 and Igf2 genes of the embryo and fetus. How would this affect the expression of the maternal and paternal alleles of the Igf2 gene after the baby is born?
A. It would not affect the expression of the maternal allele, but the paternal allele would be overexpressed.
B. It would not affect the expression of the maternal allele, but the paternal allele would be inhibited.
C. It would not affect the expression of the paternal allele, but the maternal allele would be overexpressed.
D. It would not affect the expression of the paternal allele, but the maternal allele would be inhibited.
B. It would not affect the expression of the maternal allele, but the paternal allele would be inhibited.
113
Which of the following is an example of epigenetic inheritance?
A. Expression of the Igf2 gene based on methylation of the ICR and DMR regions
B. Control of mRNA stability by an RNA-binding protein
C. Activation of transcription by a general transcription factor
D. Inheritance of flower color as studied by Mendel
A. Expression of the Igf2 gene based on methylation of the ICR and DMR regions
114
Which of the following are molecular mechanisms used in epigenetic gene regulation?
A) DNA methylation
B) Covalent histone modification
C) Chromatin remodeling
D) All of the answers are correct.
D) All of the answers are correct.
115
What general transcription factor is most often affected by regulatory transcription factors?
A) TFIIB
B) TFIID
C) TFIIE
D) TFIIF
B) TFIID
116
For a recessive single-gene disorder, the concordance among dizygotic twins should be
A) 75%
B) 100%
C) 50%
D) 25%
E) 0%
D) 25%
117
Consider the following DNA sequence, which codes the first portion of a long protein beginning at the ATG (AUG in mRNA) start codon.
5' ATG CCC CGC AGT AGG GGG TGG AGA 3'
Which of the mutated sequences listed is most likely to be a deleterious mutation?
A) 5' ATG CCC CGC AGT AGG GGG TGA AGA3'
B) 5' ATG CCG CGC AGT AGG GGG TGG AGA3'
C) 5' ATG CCC CGC AGT AGG GAG TGG AGA3'
C) 5' ATG CCC CGC AGT AGG GAG TGG AGA3'
118
Locus heterogeneity can cause difficulties in pedigree analysis since
A. the inheritance of more than one gene is being analyzed.
B. the cause of the disease may not have a genetic origin.
C. the inheritance of only one gene is being analyzed.
D. the cause of the disease may have environmental as well as genetic origins.
A. the inheritance of more than one gene is being analyzed.
119
In imprinting of the Igf2 gene in mice, are the ICR and DMR methylated on the maternal or paternal chromosome? Which chromosome expresses Igf2?
A. Maternal, paternal
B. Maternal, maternal
C. Paternal, maternal
D. Paternal, paternal
D. Paternal, paternal
120
If CAP could not bind to its CAP site, then what would be the result? Assume lactose is present in each scenario.
A. Transcription would be difficult to repress in the absence of glucose.
B. Transcription would be difficult to activate in the absence of glucose.
C. Transcription would be difficult to repress in the presence of glucose.
D. Transcription would be difficult to activate in the presence of glucose.
B. Transcription would be difficult to activate in the absence of glucose.
121
CpG islands are associated with which of the following?
A. DNA methylation
B. steroid hormone activity
C. termination of translation
D. nucleosome location
A. DNA methylation
122
What would be the result of a mutation in HSP90 that prevented its binding to the glucocorticoid receptor?
A. The hormone would not be able to bind to the glucocorticoid receptor.
B. Expression of the regulated genes would become constitutive.
C. The nuclear localization signal would no longer function.
D. Glucocorticoid receptor could not form a dimer.
B. Expression of the regulated genes would become constitutive.
123
A particular gene has a mutation in its NFR that causes it to bind abnormally tightly to histones. What effect would you expect this mutation has on the expression of this gene?
A. the promoter of the gene will be constantly available to transcription factors and RNA polymerase
B. the effect on gene expression is impossible to predict
C. the gene would encode a different protein instead
D. the expression of the gene would be abnormally low or absent
E. the expression of the gene would be abnormally high
D. the expression of the gene would be abnormally low or absent
124
Most genes imprinted by methylation are silenced. What is one exception to this rule?
A. Igf2
B. H19
C. Agouti
D. Xist
A. Igf2
125
Combinatorial factors include activators and repressors as well as
A. small effector molecules, proteins that alter the composition of nucleosomes, DNA methylation, and basal transcription factors
B. small effector molecules, proteins that alter the composition of nucleosomes, but not DNA methylation
C. proteins that alter the composition of nucleosomes and DNA methylation, but not small effector molecules
D. small effector molecules, proteins that alter the composition of nucleosomes, and DNA methylation
D. small effector molecules, proteins that alter the composition of nucleosomes, and DNA methylation
126
The complete loss of either a guanine or adenine from DNA is an example of
A. Depurination
B. Tautomeric shifts
C. Deamination
D. None of the answers are correct.
A. Depurination
127
A particular cell contains all of the standard histones but lacks several histone variants. Which of the following MAY be true of this cell?
A. The cell will express different sets of genes than other cells in the same organism.
B. The cell will be completely unable to remodel its chromatin.
C. The cell will have an enhanced ability to chemically modify its histones.
D. The cell will not be able to divide.
E. The cell will be unable to express any of its genes at all.
A. The cell will express different sets of genes than other cells in the same organism.
128
Which of the following is part of the process of X-chromosome inactivation?
A. Compaction of the active X chromosome into a Barr body
B. Expression of Xist from both chromosomes at the start of the process
C. Binding of multiple Xist transcripts to Xic on the X chromosome that will be inactivated
D. Binding of Tsix transcripts to the X chromosome to be inactivated after the Xist transcripts binds to Xic
C. Binding of multiple Xist transcripts to Xic on the X chromosome that will be inactivated
129
A disease that is lethal only in the homozygous condition is most likely which of the following?
A. autosomal recessive
B. X-linked
C. autosomal dominant
D. None of these choices are correct.
A. autosomal recessive
130
Haplotypes can be useful in the identification of disease genes since
A. the most concordant marker(s) is the disease gene.
B. no pedigree information needs to be known.
C. the most concordant marker(s) is typically the one that is closest to the disease gene.
D. the least concordant marker(s) is typically the one that is closest to the disease gene.
C. the most concordant marker(s) is typically the one that is closest to the disease gene.
131
Prions are thought to cause neurological diseases by
A. converting to a misfolded form that forms aggregates.
interfering with neuronal transmission.
B. converting to a misfolded form that is more soluble than the normally folded protein.
C. competing for the binding of a hormone that helps maintain neuronal integrity.
A. converting to a misfolded form that forms aggregates.
interfering with neuronal transmission.
132
The term for a protein infectious agent that causes disease is
A. kuru
B. prion
C. scrapie
D. proteon
B. prion
