Gentiks Exam 3
Which of the following statements CORRECTLY describes nonsense mutations? Select one: a. They cause a nonfunctional amino acid to replace a functional amino acid. b. They result in the insertion or deletion of a small number of nucleotides to the DNA. c. They convert a codon for a particular amino acid within a gene into a stop codon. d. They change the nucleotide sequence of a gene but do not change the sequence of the resulting protein. e. They cannot revert to wild type.
They convert a codon for a particular amino acid into a stop codon
A BLAST search is done to: Select one: a. predict the three-dimensional structure of a protein from its amino acid sequence. b. determine the conditions under which a gene is expressed. c. find the chromosomal location of a sequence. d. find restriction sites and SNPs in a sequence. e. find similar gene or protein sequences.
find similar gene or protein sequences
When an allele has a frequency of 1.0 in a population, it is _____ in the population. Select one: a. lost b. recessive c. dominant d. fixed e. overdominant
fixed
The Ames test is performed to determine ______________________. Select one: a. If a given stretch of DNA is methylated. b. If inbreeding has occurred. c. If there is loss of heterozygosity. d. If a compound is a mutagen. e. If a chromosomal deletion has occurred.
if the compound is a mutagen
If there are two alleles, A and a, in a population and the population is at Hardy-Weinberg equilibrium, which frequency of A would produce the greatest frequency of heterozygotes? Select one: a. 0.25 b. 0.1 c. 1 d. 0.5 e. 0.75
0.5
All the below are benefits of having the sequenced human genome, except _____. Select one: a. association studies of genetic markers and disease b. studies on the evolution of humans c. 100% accuracy in predicting disease risk d. examining genetic variation in Homo sapiens e. comparative studies of cancer cell genome vs. normal cell genome
100% accuracy is predicting disease risk
How many genes are estimated to be in the human genome? Select one: a. 2,000,000 - 2,500,000 b. 20,000 - 25,000 c. 200 - 250 d. 200,000 - 250,000
20,000 - 25,000
The Human Genome Project was completed in: Select one: a. 1990 b. 2001 c. 1986 d. 1950 e. 2011
2001
(There is a figure, but if you google Hardy-Weinburg, it's always going to be the first graph that shows up) When a population is in Hardy-Weinberg equilibrium and p = 0.1 and q = 0.9, what are the approximate genotypic frequencies? Select one: a. AA = 0.25, Aa = 0.5, aa = 0.25 b. AA = 0.2, Aa = 0.6, aa = 0.2 c. AA = 0.81, Aa = 0.18, aa = 0.01 d. AA = 0.01, Aa = 0.18, aa = 0.81 e. AA = 0.05, Aa = 0.4, aa = 0.55
AA=0.01, Aa=0.18, aa=0.81
The BRCA1 gene is found to be mutated in some forms of breast cancer. What is the normal function of this gene? Select one: a. Signal transduction with Ras b. Triggering differentiation of cells into breast tissue c. DNA repair d. Part of a cell cycle checkpoint e. Activating cell proliferation pathways
DNA repair logic: BRCA1 and BRCA2 are tumor suppression genes involved in mutation repair.
What is the purpose of Taq polymerase in a PCR reaction? Select one: a. heating of the reaction and DNA denaturation b. DNA denaturation c. heating of the reaction d. DNA synthesis e. primer annealing
DNA synthesis
Which of the following lists the CORRECT terms for these three steps of PCR, and in the correct order? Select one: a. denaturation of the double-stranded template, extension of the new DNA molecules, hybridization of the template b. denaturation of the double-stranded template, extension of the new DNA molecules, primer annealing c. degradation of the template, primer annealing, extension of the new DNA molecules d. hybridization of the single-stranded templates, primer annealing, extension of the new DNA molecules e. denaturation of the double-stranded template, primer annealing, extension of the new DNA molecules
Denaturation of the double stranded template, primer annealing, extension of the new DNA molecules
Hardy and Weinberg's achievement in genetics was demonstrating mathematically that dominant alleles should increase in frequency over time in a population. Select one: True False
False
UV light primarily damages DNA by: Select one: a. Depurinating DNA b. Deaminating bases c. Forming purine dimers, usually with As d. Alkylating DNA e. Forming pyrimidine dimers, usually with Ts
Forming pyrimidine dimers, usually with Ts
Which parts of the DNA region shown in the diagram encode proteins? (I = lac repressor gene; Z, Y, A = lac operon structural genes; P = lac promoter; O = lac operator) Select one: a. P, O, Z, Y, A b. I, Z, Y, A c. P d. I, P, O, Z, Y, A e. I, P, O
I, Z, Y, A
Many tumor cells are able divide uncontrollably in cell culture in the laboratory. Some of these cell lines have genomes with a mutant tumor-suppressor gene. Adding a wild-type copy of this tumor-suppressor gene to the genomes of these cells reduces their ability to divide in culture. In contrast, adding a wild-type copy of a proto-oncogene to the genomes of a tumor cell line with an activated oncogene doesn't have any effect on the uncontrolled cell division shown by this line. Which of the following statements BEST explains why adding a wild-type proto-oncogene doesn't affect cell division in these cell lines? Select one: a. Many proto-oncogenes are inherited as recessive mutations. b. Many proto-oncogenes encode proteins involved in DNA repair. c. Most protein products of proto-oncogenes don't have a role in cell division. d. Most point mutations that produce activated oncogenes are dominant gain-of-function mutations. e. Many proto-oncogenes encode proteins that act to promote apoptosis.
Most point mutations that produce activated oncogenes are dominant gain-of-function mutations
Which of the following remains a problem of gene therapy using viral-derived vectors? Select one: a. To date, there has not been a case of gene therapy curing a disease. b. Patients mount immune responses to the transferred gene and vectors. c. We do not have the ability to use somatic gene therapy at this time. d. We have yet to develop a vector for delivering the gene. e. We can only alter germ-line cells at this time.
Patients mount immune responses to the transferred gene and vectors
Which of the following processes is also known as RNA silencing or posttranscriptional gene silencing? Select one: a. RNA splicing b. protein degradation c. transcriptional stalling d. transcriptional repression e. RNA interference
RNA interference
The FBI has developed the Combined DNA Index System (CODIS) to identify individuals by their DNA profiles. This has proven to be very useful in range of forensic applications. What type of markers are used in CODIS? Select one: a. CRISPR b. Restriction enzyme cut sites c. Short tandems repeats (STRs), also known as microsatellites d. Mitochondria e. Plasmids
STRs, or microsatellites
In the presence of both lactose and glucose, which of the following occurs with the E. coli lac operon? Select one: a. The lacZ and lacY genes are fully expressed. b. The cAMP-CAP complex is not available to bind near or at the lac promoter. c. Lactose is converted to glucose and galactose. d. The lacI gene does not produce repressor. e. Lactose binds to the operator.
The cAMP-CAP complex is not available to bind near or at the lac promoter
The gene p53 is found to be mutated in many different types of cancers. The protein made by this gene has multiple functions, but some of the most important involve response to DNA damage, roles in DNA repair, and apoptosis. What would you expect to see regarding the p53 mutations in cancerous cells? Select one: a. These are allozygous mutations b. These are dominant mutations c. These are recessive mutations d. These are epistatic mutations e. These are gain of function mutations
These are recessive mutations
Which of the following statements about somatic mutations is FALSE? Select one: a. They may be inherited by the offspring of individuals in which the mutation occurred. b. Some may give rise to cancers in humans and other animals. c. They may result in inactive gene products of the mutated genes. d. They may result from both frameshift and base-pair substitution mutations. e. They may be inherited by daughter cells after cell division.
They may be inherited by the offspring of individuals in which the mutation occurred
What is the function of dideoxynucleotides in Sanger DNA sequencing? Select one: a. They stop (terminate) synthesis at a specific site, so the base at that site can be determined. b. They act as primers for reverse transcriptase. c. They cut the sequenced DNA at specific sites. d. They act as primers for DNA polymerase. e. They allow only the specific sequencing of the RNAs of a genome.
They terminate synthesis at a specific site so the base at that site can be determined
On my honor, I have neither given nor received unauthorized assistance on this assignment. Please type your name below. (In this case, "unauthorized assistance" means any help on the exam from another individual.)
This is where you're supposed to feel bad. And I mean really, really bad. Like, "forgot to turn the stove off" bad.
An example of a gene product encoded by a regulatory gene is: Select one: a. an operator. b. the beta-galactosidase enzyme. c. a terminator. d. a repressor protein. e. allolactose.
a repressor protein
In nucleotide excision repair of DNA damage, which of the following takes place? Select one: a. A damaged single base is repaired in the double helix b. A stretch of DNA is removed and resynthesized using the other strand as a template c. Blunt ends of the DNA are rejoined. d. Energy from white light is harnessed to repair damaged bases
a stretch of DNA is removed and resythesized using the other strand as a template
In Burkitt lymphoma, there is increased expression of the c-MYC gene. Which of the following statements BEST explains the reason for the increased expression of this gene? Select one: a. A translocation has brought the c-MYC gene next to a different regulatory region. b. The c-MYC gene has been amplified. c. A chromosome deletion has removed a tumor-suppressor gene. d. A chromosome duplication involves a segment with an oncogene. e. A chromosome deletion has removed an oncogene.
a translocation has brought the c-MYC gene next to a different regulatory region
What is the origin of the CRISPR-Cas9 system? Select one: a. A gene regulation system found in plants b. A type of immune system found in bacteria c. A meiosis control method found in yeast d. An RNAi system found in Drosophila
a type of immune system found in bacteria
In human gene therapy, ___________________ are commonly used to insert genes into recipient cells. Select one: a. β-galactosidase b. Adeno-associated viruses c. Gene guns d. E. coli e. Plasmids
adeno-associated viruses
The increased levels of telomerase associated with many tumor cells likely promote cancer by: Select one: a. decreasing the number of epigenetic changes that would promote cancer. b. reducing the expression of several oncogenes. c. allowing cells to continue to divide when normally chromosomes should shorten beyond a point where division would be no longer possible. d. promoting the efficiency of the spindle-assembly checkpoint. e. enhancing levels of DNA repair so that cells remain normal and have stable genomes and thus would be able to replicate their DNA and divide more often.
allowing cells to continue to divide when normally chromosomes should shorten beyond a point where division would no longer be possible
If there is increased inbreeding in a population, which of the following changes will be observed? Select one: a. Changes in the allele frequencies b. An increase in the number of dominant alleles in the population c. An increase in homozygotes d. An increase in heterozygotes e. An increase in banjo music
an increase in homozygotes but, y'know, probably more banjos too.
The CRISPR repeat sequences were originally identified in bacteria. What is their function in bacteria? Select one: a. As a buffering system, so that there would be backup copies of any sequences that were mutated. b. To repair the pyrimidine dimers caused by UV light exposure. c. As a type of immune system, to aid in recognizing and destroying phage viruses. d. To regulate genes associated with cell proliferation. e. To aid in the repair of double-stranded breaks in DNA, via homology dependent repair.
as a type of immune system to aid in recognizing and destroying phage viruses
For a physical map of a chromosome, distances are measured in units of: Select one: a. RFLPs. b. base pairs. c. contigs. d. centiMorgans. e. map units.
base pairs
Which of the following is actually an implication of the Hardy-Weinberg equilibrium? Select one: a. Allele frequencies will remain constant from generation to generation. b. After one generation of random mating, assuming the other assumptions are met, genotypic frequencies will be at Hardy-Weinberg equilibrium. c. Dominant alleles will increase in frequency over time. d. Recessive alleles will increase in frequency over time. e. Both a and b.
both a and b
Which of the following is the major event associated with the retinoblastoma cancer? Select one: a. inactivation of a major DNA repair system b. a translocation resulting in the enhanced expression of an oncogene c. a mutation resulting in an activated ras oncogene d. both copies of a tumor-suppressor gene being inactivated e. a translocation involving chromosomes 9 and 22
both copies of a tumor-suppressor gene being inactivated
A number of somatic translocations have been associated with specific types of ___________ in humans. An example of this is the "Philadelphia chromosome", a chromosome 9:22 translocation. Select one: a. Cockayne Syndrome b. Cancer c. Tay-Sachs disease d. Cystic fibrosis e. Phenylketonuria
cancer
For a genetic map of a chromosome, distances are measured in units of: Select one: a. RFLPs. b. contigs. c. restriction sites. d. base pairs. e. centiMorgans.
centiMorgans
A promoter that affects only genes that are on the same piece of DNA is referred to as a(n) _____ promoter. Select one: a. trans acting b. positive c. enhanceable d. cis acting e. negative
cis acting
A condition in which a gene or group of genes is expressed all the time is __________. Select one: a. Translated b. Transcribed c. Constitutive d. Induced e. Activated
constitutive
Huntington disease can strike at an earlier age and bring about a more rapid degeneration and death in successive generations within a family. This phenomenon can be explained by which mechanism? Select one: a. presence of a transposable element in the gene b. presence of an extra chromosome in the germ line c. chronic exposure to mutagens in the environment d. absence of a gene product that is involved in DNA repair e. expansion of a trinucleotide repeat in the coding sequence of the gene
expansion of a trinucleotide repeat in the coding sequence of the gene
For a given population, the frequency of the B allele is 0.7, and the frequency of the b allele is 0.3. What genotypic frequencies would be expected under Hardy-Weinberg equilibrium? Select one: a. f(B/B) = 0.7; f(B/b) = 0.2; f(b/b) = 0.1 b. f(B/B) = 0.36; f(B/b) = 0.48; f(b/b) = 0.16 c. f(B/B) = 0.49; f(B/b) = 0.42; f(b/b) = 0.09 d. f(B/B) = 0.7; f(B/b) = 0; f(b/b) = 0.3 e. f(B/B) = 0.6; f(B/b) = 0.2; f(b/b) = 0.2
f(B/B) = 0.49; f(B/b) = 0.42; f(b/b) = 0.09
Helen has type I osteogenesis imperfecta (OI), a genetic skeletal disorder. Shown below is her DNA sequence for a portion of the coding region of the collagen type I gene, which contains the mutation responsible for her disorder. The corresponding wild-type sequence is shown also (only one DNA strand is shown in each case). Helen 5'-ACTCCACTTCTTCCAGTAC-3' Normal 5'-ACTCACTTCTTCCAGTAC-3' What type of mutation does Helen carry? Select one: a. silent b. transition c. missense d. frameshift e. nonsense
frameshift
Through _____, alleles may disappear from a population simply by chance. Select one: a. genetic rescue b. negative directional selection c. fixation d. underdominance e. genetic drift
genetic drift
In the Ames test, an extract of liver enzymes is added to the compound to be tested. What is the reason for this? Select one: a. In some cases, compounds themselves are not mutagenic, but they are converted to mutagenic compounds by enzymes in the liver. b. The liver enzymes will enable base-excision repair. c. The enzymes will provide histidine. d. The Ames test can determine if a compound binds to DNA and binds to proteins at the same time. e. Bacteria will grow better with the addition of liver enzymes.
in some cases, compounds themselves are not mutagenic, but they are converted to mutagenic compounds by enzymes in the liver
A mutant E. coli strain is found that synthesizes β-galactosidase in the absence of glucose whether or not lactose is present. What two mutations might lead to this outcome? Select one: a. lacIs mutation or lacOc mutation b. lacP- mutation or lacIs mutation c. lacI- mutation or lacOc mutation d. lacP- mutation or lacI- mutation e. lacP- mutation or lacOc mutation
lacI- mutation or lacOc mutation
A lac operon of genotype lacI+ lacP+ lacO+ lacZ+ lacY- will produce β-galactosidase but not permease when: Select one: a. glucose and lactose are both present. b. lactose is absent. c. in the presence or absence of lactose. d. glucose is present. e. lactose is present.
lactose is present
Which of the following is a disadvantage of map-based sequencing versus shotgun sequencing? Select one: a. The relationship of overlapping fragments to sequences is known before sequencing begins. b. Map-based sequencing yields well-characterized physical maps as well as actual sequences. c. Map-based sequencing is more time-consuming because extensive mapping is required before sequencing starts. d. Map-based sequencing minimizes the amount of repeat sequencing in which the same region is sequenced several times. e. Restriction patterns can be used to identify overlapping clones.
map-based sequencing is more time-consuming because extensive mapping is required before sequencing starts
"Next-generation" DNA sequencing commonly refers to which sequencing method? Select one: a. Dideoxy sequencing b. Capillary sequencing c. Massively parallel sequencing d. Sanger sequencing
massively parallel sequencing
A _____ mutation changes a codon that specifies an amino acid into one that terminates translation. Select one: a. nonsense b. missense c. neutral d. reverse e. silent
nonsense
Evidence that the development of cancer is a multistep process includes the: Select one: a. observation that certain tumor-suppressor genes and oncogenes are involved in a sequential manner in the development of colon cancer. b. fact that some viruses are associated with cancer. c. fact that proto-oncogenes are widely conserved in evolution. d. fact that there are many genetic and epigenetic mechanisms that lead to inactivation of the same tumor-suppressor gene. e. development of a cancer as a result of activation of a single oncogene by any of a variety of mechanisms.
observation that certain tumor-suppressor genes and oncogenes are involved in a sequential manner in the development of colon cancer
You are studying a population of five-lined skinks in the Upper Peninsula, and are interested in effects that their small isolated subpopulations may have had on the genetics of the population. You genotype 100 skinks for a polymorphic gene locus, and find the following genotypic frequencies: B/B >> 0.4 B/b >> 0.4 b/b >> 0.2 What are the allele frequencies for this population? Select one: a. p = 0.7 and q = 0.3 b. p = 0.5 and q = 0.5 c. p = 0.6 and q = 0.4 d. p = 0.6 and q = 0.2 e. p = 0.8 and q = 0.2
p=0.6 and q=0.4
Normal cellular genes whose products are involved in facilitating cell division to occur under appropriate conditions are called: Select one: a. driver genes. b. inhibitor genes. c. tumor-suppressor genes. d. proto-oncogenes. e. passenger genes.
proto-oncogenes
Which of the following describes the modification of histones associated with the nucleosomes of actively transcribed genes? Select one: a. Rich in acetyl groups (hyperacetylated) b. Rich in phosphate groups (hypophosphorylated) c. Poor in acetyl groups (hypoacetylated) d. None of the above e. Poor in phosphate groups (hyperphosphorylated)
rich in acetyl groups (hyperacetylated)
A geneticist uses genetic engineering to treat patients who have an immune disorder caused by a mutation in the gene for adenosine deaminase. The geneticist removes white blood cells from the patients, transfers a functional gene for adenosine deaminase into the cells, and then infuses the treated cells back into the patient. This is an example of which type of gene therapy? Select one: a. neither somatic nor germline gene therapy b. germline gene therapy c. somatic gene therapy d. both somatic and germline gene therapy
somatic gene therapy
The SNRPN gene in humans is known to be maternally imprinted. This means that: Select one: a. The allele that comes from the mother is inactivated. b. Different enhancers are present in the maternal and paternal alleles. c. One of the X chromosomes is randomly inactivated d. The allele that comes from the father is inactivated. e. None of the above.
the allele that comes from the mother is inactivated
In the genetic map of the human genome, one map unit is approximately 850,000 bp. For the genome of the eukaryotic yeast Saccharomyces cerevisiae, one map unit is approximately 3000 bp. Why is a map unit so different in these two different types of organisms? Select one: a. A map unit is the amount of measured recombination between two linked points in a genome, and humans have more SNPs than Saccharomyces cerevisiae that can serve as genetic markers. b. Saccharomyces cerevisiae has fewer predicted genes than humans, which means that less recombination is required in yeast cells. c. An increased number of noncoding introns in humans suppresses recombination and leads to larger physical distances for each map unit. d. The amount of homologous recombination per DNA length must be lower in humans than in Saccharomyces cerevisiae. e. Humans have more chromosomes and, therefore, have more linkage groups than Saccharomyces cerevisiae.
the amount of homologous recombination per DNA length must be lower in humans than in Saccharomyces cerevisiae
By the early 1980s, the population of Florida panthers had dwindled to fewer than 30. Within this population, there was a high frequency of detrimental traits, including low sperm count and undescended testicles in males and kinked tails in both sexes. The future for this iconic population was bleak at best. Which of the following provides the BEST explanation for the observed detrimental traits? Select one: a. The mutation rate in this population is very high due to the small number of individuals. b. Migration of individuals into this population has introduced more detrimental traits. c. Recurrent mutation and natural selection are acting as opposing forces on this population and an equilibrium has not yet been reached. d. Natural selection is acting in this population and resulting in more individuals with detrimental traits. e. The population is experiencing a genetic bottleneck, where the genetic variation is declining and harmful alleles are drifting to high frequencies.
the population is experiencing a genetic bottleneck, where the genetic variation is declining and harmful alleles are drifting to high frequencies
In the polymerase chain reaction (PCR), the solution is cooled to a moderate temperature in the second step of the cycle - usually, somewhere between 50 and 60 °C. What is happening during this step of the reaction? Select one: a. The two strands of DNA separate. b. The DNA polymerase synthesizes new DNA strands. c. The radioactively labeled probes will bind to regions of complementary DNA fragments. d. The primers anneal to the template DNA. e. The single-stranded molecules hybridize to form double-stranded DNA.
the primers anneal to the template DNA
A geneticist is studying a mutation in a population of turtles that causes their shells to become extremely brittle. She determines the mutation is caused by the loss of two nucleotides in the coding region of a gene. Upon studying the mutant protein that is produced, she observes that it is 312 amino acids in length, as compared to the normal protein that is 588 amino acids in length. This mutant protein can no longer carry out its normal function of assisting in the hardening of a turtle's shell. Which of the following terms do NOT describe this mutation? Select one: a. nonsense mutation b. transversion c. deletion d. loss-of-function mutation e. frameshift mutation
transversion
Inhibitory genes involved in cancer are called _____ and stimulatory genes involved in cancer are called _____. Select one: a. stimulatory cancer genes; inhibitory cancer genes b. oncogenes; tumor-suppressor genes c. tumor-suppressor genes; oncogenes d. inhibitory cancer genes; stimulatory cancer genes e. none of the above
tumor-suppressor genes; oncogenes
A patient's cells from a colorectal polyp were collected and the APC and ras genes were analyzed. The APC gene was found to be mutated, and the ras gene was found to be up-regulated. The physician classifies the polyp an adenoma and advises the patient to have the polyp removed. The patient claims that the physician is incorrect in his advice to have the polyp removed. Is the physician's advice logical? Why or why not? Select one: a. yes, because the cells of the polyp have already begun to divide inappropriately, and further mutations may allow the tumor to invade other tissues and metastasize b. no, because until the specific function of the mutated APC gene is known, it cannot be determined that the cells are in a proliferative state c. no, because the up-regulation of the ras gene will counter the effects of the mutant APC gene, and the benign tumor is unlikely to progress to a malignant state d. no, because adenomas are benign tumors and thus are unlikely to progress to a malignant tumor e. yes, because up-regulation of the ras gene is causing the cells to divide more slowly, and thus they will be unable to repair future DNA damage that will likely occur in cells surrounding the polyp
yes, because the cells of the polyp have already begun to divide inappropriately, and further mutations may allow the tumor to invade other tissues and metastasize Listen to your f*cking doctor
