Genetics Final
Under normal conditions, a population is in Hardy-Weinberg equilibrium at 'gene A' and the frequency of alleles A = 0.5. Under drought conditions, the aa genotype is lethal (waa = 0). What will be the frequency of the a allele if the population is exposed to drought conditions for 4 generations? A. .17 B. .14 C. .25 D. .33. E. 50
A. .17
A certain form of albinism in humans is recessive and autosomal. Assume that 1 percent of the individuals in a given population are albino. Assuming that the population is in Hardy-Weinberg equilibrium, what is the likelihood that a person sampled from that population a carrier for albinism? A. .18 B. .81 C. .01 D. .90 E. .10
A. .18
Given that p = 0.3 for a population in Hardy-Weinberg equilibrium, what would be the expected frequency of heterozygotes for the involved allelic pair? A. .42 B. 49. C. .09 D. .60 E. .50
A. .42
In a three-point mapping experiment, how many different genotypic classes are expected? How many phenotypic classes? A. 8; 8 B. 16; 8 C. 3; 3 D. 8; 4 E. 16; 4
A. 8; 8
What is the unit of distance between genes based on a physical map? A. map units B. base pairs C. centiMorgans D. inches E. lod scores
B. base pairs
Methods for determining the linkage group and genetic map in humans involve ________. A. gamete genotyping B. tetrad analysis and bromodeoxyuridine C. twin spots and tetrad analysis D. dihybrid test crosses E. DNA markers
E. DNA markers
How does CRISPR behave as a form of bacterial adaptive immunity? A. Cas genes encode complementary DNA to phage genomes. B. CRISPR nucleases trigger apoptosis. C. CRISPR repeats provide molecular memory of infection. D. CRISPR loci encodes antibody proteins. E. Spacer sequences provide a molecular memory of past viral attacks.
E. Spacer sequences provide a molecular memory of past viral attacks.
Which term is given to the total genetic information carried by all members of a population? A. chromosome complement B. breeding unit C. race D. genome E. gene pool
E. gene pool
A neutral mutation is one that ________ A. is heavily favored by selection B. is found only in regulatory regions of the genome C. is quickly eliminated by selection D. is found only in coding regions of the genome E. produces an allele that is functionally equivalent to the original allele
E. produces an allele that is functionally equivalent to the original allele
Which of the following is not included in the list of assumptions that pertain to a population in a Hardy-Weinberg equilibrium? A. no migration B. random mating C. no new alleles are generated by mutation D. large population size and no genetic drift E. some genotypes may have a selective advantage
E. some genotypes may have a selective advantage
When referring to attenuation in regulation of the trp operon, it would be safe to say that when there are high levels of tryptophan available to the organism, ________. A. the trp operon is being transcribed at relatively high levels B. translational termination is likely C. tryptophan is inactivating the repressor protein D. ribosomes are stalling during translation of the attenuator region E. transcriptional termination is likely
E. transcriptional termination is likely
The bacterial chromosome
Functional beta-galactosidase protein could be made from
A(n) ________ is a stretch of DNA consisting of an operator, a promoter, and genes for a related set of proteins, usually making up an entire metabolic pathway.
Operon
The bacterial chromosome
Repressor protein is able to bind to the operator region on
The F prime plasmid
Repressor protein is made from
Compare and contrast X-linked dominant and X-linked recessive inheritance patterns
X-linked dominant: A. The trait appears about equally prevalent in males and females B. If an affected male mates with a normal female, then all daughters and no sons will be affected C. If a normal male mates with a heterozygous female, then half of daughters and sons will be affected D. The phenotype of the disease is seen in every generation X-linked Recessive: A. There is a greater prevalence of affected males B. The phenotype of the disease may skip generations C. If an affected male mates with a normal female, then neither daughters nor sons will show the disease phenotype D. If a normal male mates with a heterozygous female, then half of sons will be affected and daughters will not show the disease phenotype
With the use of dialysis against _____________________, Gilbert and Muller-HIll were able to identify the repressor in certain extracts of _______ cells.
a radioactive gratuitous inducer (IPTG); lac l^q
Sexual _______ is the complex set of responses by cells, tissues, and organs to those genetic signals. In sexual ______ , genes signal developmental pathways whereby the sexes are generated.
differentiation; determination
In a population of 100 individuals, 49 percent are of the NN blood type. What percentage is expected to be MN assuming Hardy-Weinberg equilibrium conditions? A. 42 percent B. 9 percent C. 51 percent D. 21 percent E. There is insufficient information to answer this question.
A. 42 percent
How do sex chromosomes contrast with autosomes? Select the three correct statements. A. In some species, the lack of sex chromosomes (one or both) is not lethal to the organism. B. Compensation mechanisms exist for having extra autosomes, but not extra sex chromosomes. C. Sex chromosomes carry genes coding for the synthesis of sex hormones. D. In a diploid organism, one member of the sex chromosome pair may be inactivated without significant consequences. E. Sex chromosomes carry genes responsible for the development of male or female gonads. F. In a diploid organism, sex chromosomes are represented by homomorphic pairs in both sexes.
A. In some species, the lack of sex chromosomes (one or both) is not lethal to the organism. D. In a diploid organism, one member of the sex chromosome pair may be inactivated without significant consequences. E. Sex chromosomes carry genes responsible for the development of male or female gonads.
How does nondisjunction in human female gametes give rise to Klinefelter and Turner syndrome offspring following fertilization by a normal male gamete? A. Nondisjunction results in ova that carry either two X chromosomes or none. The former results in Klinefelter syndrome when fertilized by a Y-containing sperm, and the latter results in Turner syndrome when fertilized by an X-containing sperm. B. Nondisjunction results in ova that carry either two X chromosomes or none. The former results in Turner syndrome when fertilized by a Y-containing sperm, and the latter results in Klinfelter syndrome when fertilized by an X-containing sperm. C. Nondisjunction results in ova that carry either two X chromosomes or none. An ovum with no X chromosomes results in Klinefelter syndrome when fertilized by a Y-containing sperm, and in Turner syndrome when fertilized by an X-containing sperm. D. Nondisjunction results in ova that carry either two X chromosomes or none. An ovum with two X chromosomes results in Klinefelter syndrome when fertilized by a Y-containing sperm, and in Turner syndrome when fertilized by an X-containing sperm. E. Nondisjunction of complete sets of chromosomes leads to ova that are either diploid, or completely devoid of chromosomes. A diploid ovum results in Klinefelter syndrome when fertilized by a Y-containing sperm, and results in Turner syndrome when fertilized by an X-containing sperm.
A. Nondisjunction results in ova that carry either two X chromosomes or none. The former results in Klinefelter syndrome when fertilized by a Y-containing sperm, and the latter results in Turner syndrome when fertilized by an X-containing sperm.
What three essential criteria must be met in order to execute a successful mapping cross? Select the three correct statements. A. One parent should be heterozygous and the other homozygous recessive for all the genes being mapped. B. Sufficient progeny must be generated to ensure observation of rare crossover products. C. The phenotypes of the offspring must be similar to each other to ensure observation of rare crossover products. D. The genotypes of the offspring must be readily determined from their phenotypes. E. If crossing over in an organism is limited to one sex, the homozygous individual must be of the sex in which crossing over occurs. F. One parent should be homozygous dominant and the other homozygous recessive for all the genes being mapped.
A. One parent should be heterozygous and the other homozygous recessive for all the genes being mapped. B. Sufficient progeny must be generated to ensure observation of rare crossover products. D. The genotypes of the offspring must be readily determined from their phenotypes.
Which of the following statements regarding sexual differentiation in humans is FALSE? A. The presence of two X chromosomes determines whether the gonadal ridges develop into ovaries or testes. B. The embryo is hermaphroditic until primordial germ cells migrate to gonadal ridges. C. Because gonadal ridges can form either ovaries or testes, they are called bipotential gonads. D. Sexual differentiation occurs very early in embryonic development.
A. The presence of two X chromosomes determines whether the gonadal ridges develop into ovaries or testes.
Why does more crossing over occur between two distantly linked genes than between two genes that are very close together on the same chromosome? Select the two correct reasons. A. Two loci that are far apart are more likely to have a crossover between them than two loci that are close together. B. Crossing over frequency depends on long-range ordered hydrophobic forces. C. Crossing over is somewhat randomly distributed over the length of the centromeres and telomeres. D. Two genes that are far apart are more likely to have a crossover between them than two genes that are close together. E. Crossing over frequency depends on the flexibility of a specific chromosomal region. F. Crossing over is somewhat randomly distributed over the length of the chromosome.
A. Two loci that are far apart are more likely to have a crossover between them than two loci that are close together. F. Crossing over is somewhat randomly distributed over the length of the chromosome.
Which of the following elements of the trp operon is involved in a process that "weakens or impairs" expression of the operon? A. attenuator B. promoter C. operator D. leader sequence E. repressor
A. attenuator
If lactose is accumulating outside of E. coli and is unable to enter, then which structural gene of the lac operon is most likely mutated? A. lacY B. lacI C. lacZ D. lacA E. lacX
A. lacY
The genes for the recessive traits of mahogany eyes and ebony body are approximately 25 map units apart on chromosome III in Drosophila. Assume that a mahogany-eyed female was mated to an ebony-bodied male and that the resulting F1 phenotypically wild-type females were then mated to mahogany, ebony males. Of 1000 offspring, what would be the expected phenotypes, and in what numbers would they be expected? A. mahogany = 375; ebony = 375; wild-type = 125; mahogany-ebony = 125 B. wild-type = 400; mahogany-ebony = 400; mahogany = 100; ebony = 100 C. wild-type = 375; mahogany-ebony = 375; mahogany = 125; ebony = 125 D. wild-type = 250; mahogany-ebony = 250; mahogany = 250; ebony = 250 E. mahogany = 400; ebony = 400; wild-type = 100; mahogany-ebony = 100
A. mahogany = 375; ebony = 375; wild-type = 125; mahogany-ebony = 125
Allele frequencies within a population can be altered by all except which of these processes? A. nonrandom mating B. migration C. mutation D. natural selection
A. nonrandom mating
Which of the following terms best characterizes catabolite repression associated with the lac operon in E. coli? A. positive control B. repressible system C. constitutive D. negative control E. inducible system
A. positive control
Which of the following statements is not associated with sister chromatid exchanges? A. provide new allelic combinations B. occur during mitosis C. are found elevated in the human disorder Bloom syndrome D. are observable as patch-like patterns after two rounds of replication in the presence of BrdU E. increase with exposure to mutagenic agents
A. provide new allelic combinations
Assume that the genes for the recessive traits of tan body and bare wings are 15 map units apart on chromosome II in Drosophila. Assume also that a tan-bodied, bare-winged female was mated to a wild-type male and that the resulting F1 phenotypically wild-type females were then mated to tan-bodied, bare-winged males. Of 1000 offspring, what would be the expected phenotypes, and in what numbers would they be expected? A. wild type = 425; tan-bare = 425; tan = 75; bare = 75 B. wild type = 150; tan-bare = 150; tan = 350; bare = 350 C. wild type = 500; tan-bare = 200; tan = 200; bare = 100 D. wild type = 75; tan-bare = 75; tan = 425; bare = 425 E. wild type = 350; tan-bare = 350; tan = 150; bare = 150
A. wild type = 425; tan-bare = 425; tan = 75; bare = 75
Assume that there are 12 map units between two loci in the mouse and that you are able to microscopically observe meiotic chromosomes in this organism. If you examined 200 primary oocytes, in how many would you expect to see a chiasma between the two loci? A. 6 B. 48 C. 98 D. 24 E. 12
B. 48
Assume that two genes are 80 map units apart on chromosome II of Drosophila and that a cross is made between a doubly heterozygous female and a homozygous recessive male. What percent recombination would be expected in the offspring of this type of cross? A. 20 percent B. 50 percent C. 0 percent D. 40 percent E. 80 percent
B. 50 percent
Albinism is an autosomal recessive trait in humans. Assume that there are 100 albinos (aa) in a population of 1 million. How many individuals would be expected to be homozygous normal (AA) under equilibrium conditions? A. 999,900 B. 980,100 C. 19,800 D. 10,000 E. 100
B. 980,100
Some lac operon mutations allow for beta galactosidase to be expressed constitutively even in the absence of lactose. Which of the following lac genotypes would allow for this constitutive expression? A. I+ P+ O+ Z- Y+ A+ B. I+ P+ Oc Z+ Y+ A+ C. Is P+ O+ Z+ Y+ A+ D. I+ P- O+ Z+ Y+ A+ E. I+ P+ O+ Z+ Y+ A+
B. I+ P+ Oc Z+ Y+ A+
A constitutive mutation in the lac operon may be of several types. Name two types of constitutive mutations. A. LacY- and LacI- B. LacI- and LacO^c C. LacZ- and LacI- D. LacO^c and LacZ- E. LacY- and LacA-
B. LacI- and LacO^c
In a population of 10,000 individuals, in which 3600 are MM, 1600 are NN, and 4800 are MN, what are the frequencies of the M alleles and the N alleles? A. M = 0.36; N = 0.64 B. M = 0.6; N = 0.4 C. M = 0.4; N = 0.6 D. M = 0.64; N = 0.36 E. M = 0.36; N = 0.16
B. M = 0.6; N = 0.4
In the Hardy-Weinberg equation the term p2 represents: A. The observed number of one category of homozygotes an equilibrium population with allele frequencies p and q. B. The expected number of one category of homozygotes in an equilibrium population with allele frequencies p and q. C. The observed number of heterozygotes an equilibrium population with allele frequencies p and q. D. The expected number of heterozygotes an equilibrium population with allele frequencies p and q.
B. The expected number of one category of homozygotes in an equilibrium population with allele frequencies p and q.
The CRISPR-Cas mechanism includes three steps. Which of the following represents the third and final step? A. The third step is known as new spacers insertion. B. The third step is known as target interference. C. The third step is known as spacer acquisition. D. The third step is known as crRNA biogenesis.
B. The third step is known as target interference.
Which of the following statements describes the members of a population? A. They can include all of the plants and animals within a geographic area. B. They must be able to interbreed with one another. C. They must have the same allele for at least one genetic locus. D. They all have the same genotype.
B. They must be able to interbreed with one another.
Although the vast majority of women who inherit a single copy of an X-linked recessive disease allele are not affected by the disorder, a small percentage of women do display the disease phenotype. Which of the following could explain this rare phenomenon? Select all that apply. A. incomplete penetrance of the X-linked recessive allele B. Turner syndrome (a sex-chromosome aneuploidy in which women have only one X chromosome) C. multiple alleles of the X-linked recessive trait D. X-inactivation that favors inactivation of the normal X chromosome
B. Turner syndrome (a sex-chromosome aneuploidy in which women have only one X chromosome) D. X-inactivation that favors inactivation of the normal X chromosome
Which of the following is involved in catabolite repression of the lac operon? A. glucose and galactose B. glucose C. lactose D. galactose E. isoporpylthiogalactoside
B. glucose
Which term would be applied to a regulatory condition that occurs when protein is associated with a particular section of DNA and greatly reduces transcription? A. positive control B. negative control C. induction D. compression E. reduction
B. negative control
lacI codes for a(n) ________, and when lacI is mutated, the lac operon is ________. A. activator; never expressed B. repressor; constitutively expressed C. repressor; never expressed D. activator; constitutively expressed E. structural gene; never expressed
B. repressor; constitutively expressed
In the Hardy-Weinberg equation the term (2pq) represents ________. A. the expected number of homozygotes in an equilibrium population with allele frequencies p and q B. the expected number of heterozygotes an equilibrium population with allele frequencies p and q C. the observed number of heterozygotes an equilibrium population with allele frequencies p and q D. the observed number of homozygotes an equilibrium population with allele frequencies p and q
B. the expected number of heterozygotes an equilibrium population with allele frequencies p and q
Phenotypically wild-type F1 female Drosophila, whose mothers had light eyes (lt) and fathers had straw (stw) bristles, produced the following offspring when crossed to homozygous light-straw males: Phenotype: light-straw : 22 wild-type : 18 light : 990 straw : 970 Total : 2000 Compute the map distance between the light and straw loci. A. 98 map units B. 0.02 map units C. 2.0 map units D. 20 map units E. 0.98 map units
C. 2.0 map units
What is the theoretical limit of observed recombination due to crossing over? A. 1% B. 25% C. 50% D. 100%
C. 50%
Applying Hardy-Weinberg equilibrium, how many genotypes are predicted for a gene that has three alleles? A. 3 B. 4 C. 6 D. 9
C. 6
Red-green color blindness is an X-linked recessive disorder. In a population (n = 1000) that contains an equal number of males and females, the frequency of the normal allele, X 1, is 0.90 and the frequency of the mutant allele that causes color blindness, X 2, is 0.10. How many females in this population are carriers of the red-green colorblindness trait? Assume that the population is in Hardy-Weinberg equilibrium. A. 5 B. 10 C. 90 D. 180 E. More information is needed to answer this question
C. 90
What is the role of the lacZ gene product, the enzyme beta-galactosidase? A. It facilitates the entry of lactose into the bacterial cell. B. It removes the toxic by-products of lactose digestion from the bacterial cell. C. It converts lactose to glucose and galactose. D. It converts simple sugars to lactose.
C. It converts lactose to glucose and galactose.
Which of the following elements is responsible for determining male sex in humans? A. MSY B. PARS C. SRY D. Xist E. Xic
C. SRY
Why are double-crossover events expected less frequently than single-crossover events? A. Double-crossover only occur on large chromosomes. B. In contrast to single-crossovers, double-crossovers occur only in the presence of mutant protein molecules. C. The probability of two crossover events occurring at the same time is much lower than the probability of one. D. During a double-crossover, one event occurs earlier and impedes the other crossover.
C. The probability of two crossover events occurring at the same time is much lower than the probability of one.
What are pseudoautosomal regions (PARs) on the sex chromosomes? A. They are hemizygous regions of the X and Y chromosomes. B. They are homozygous regions of autosomal chromosomes. C. They are homologous regions of the X and Y chromosomes. D. They are regions of the X and Y chromosomes that do not recombine during meiosis.
C. They are homologous regions of the X and Y chromosomes.
What is a riboswitch? A. inhibition of transcription based upon binding of a regulatory protein to the operator B. promotion of transcription based upon binding of a regulatory protein to the promoter C. a form of gene regulation based on secondary structure of mRNA sequences present in the 5'UTR D. a regulatory protein that binds to the promoter
C. a form of gene regulation based on secondary structure of mRNA sequences present in the 5'UTR
The genes dumpy wings (dpdp), clot eyes (clcl), and apterous wings (apap) are linked on chromosome II of Drosophila. In a series of two-point mapping crosses, the genetic distances shown below were determined. dp−ap : 42 dp−cl : 3 ap−cl : 39 What is the sequence of the three genes? A. cl−dp−ap B. ap−dp−cl C. dp−cl−ap D. dp−ap−cl
C. dp−cl−ap
Formation of the terminator structure in riboswitches is accomplished by the ________. A. aptamer B. terminator hairpin C. expression platform D. ribosome-binding site E. antiterminator hairpin
C. expression platform
The cross GE/ge × ge/ge produces the following progeny: GE/ge 404, ge/ge 396, gE/ge 97, Ge/ge 103. From these data, one can conclude that the recombinant progeny are ________. A. GE/ge and ge/ge B. GE/ge and Ge/ge C. gE/ge and Ge/ge D. ge/ge. gE/ge, and Ge/ge
C. gE/ge and Ge/ge
Assume that a cross is made between AaBb and aabb plants and that the offspring fall into approximately equal numbers of the following groups: AaBb, Aabb, aaBb, aabb. These results are consistent with ________. A. alternation of generations B. complete linkage C. independent assortment D. hemizygosity E. incomplete dominance
C. independent assortment
Which term is used to describe enzymes that are produced only when specific substrates are present in the environment? A. repressible B. constitutive C. inducible D. negatively controlled
C. inducible
Sex determination and sexual differentiation is controlled by ____________. A. homologous chromosomes B. genetic information on autosomes C. sex chromosomes D. the homogametic sex
C. sex chromosomes
In a particular environments, a heritable trait which is intermediate in the phenotypic spectrum has a higher probability to survive and reproduce than other phenotypes. This is a case of ________. A. disruptive selection B. artificial selection C. stabilizing selection D. relative selection E. directional selection
C. stabilizing selection
In a population that meets the Hardy-Weinberg equilibrium assumptions, 81 percent of the individuals are homozygous for a recessive allele. What percentage of the individuals would be expected to be heterozygous for this locus in the next generation? A. 1% B. 81% C. 9% D. 18% E. 50%
D. 18%
Assume that in a Hardy-Weinberg population, 9 percent of the individuals are of the homozygous recessive phenotype. What percentage are homozygous dominant? A. 25% B. 42% C. 91% D. 49% E. 30%
D. 49%
Which of the following elements allows for homologous pairing in meiosis? A. SRY B. MSY C. Xist D. PARS E. Xic
D. PARS
Which of the following statements about XYY males is true? A. They are likely to end up in prison. B. They have underdeveloped secondary sex characteristics. C. They are sterile. D. They are generally taller than average.
D. They are generally taller than average.
The enzyme responsible for making cAMP is ________. A. ATP synthetase B. tryptophan synthetase C. transacetylase D. adenyl cyclase E. cAMP syntetase
D. adenyl cyclase
When tryptophan is scarce in the cell what mRNA secondary structure forms? A. terminator hairpin B. ribosome-binding site C. expression platform D. antiterminator hairpin E. aptamer
D. antiterminator hairpin
Which of the following is the ligand binding site of a riboswitch? A. terminator hairpin B. antiterminator hairpin C. ribosome-binding site D. aptamer E. expression platform
D. aptamer
In a particular environment, a heritable trait and at one end of the phenotypic spectrum has a higher probability to survive and reproduce than other phenotypes. This is a case of ________. A. stabilizing selection B. disruptive selection C. relative selection D. directional selection E. artificial selection
D. directional selection
In a particular environments, a heritable trait which is intermediate in the phenotypic spectrum has a lower probability to survive and reproduce relative to phenotypes at either extreme. This is a case of ________. A. relative selection B. stabilizing selection C. artificial selection D. disruptive selection E. directional selection
D. disruptive selection
When two genes fail to assort independently, the term normally applied is ________. A. Mendelian inheritance B. discontinuous inheritance C. dominance and/or recessiveness D. linkage E. tetrad analysis
D. linkage
Assume that a cross is made between AaBb and aabb plants and that the offspring occur in the following numbers: 106 AaBb, 48 Aabb, 52 aaBb, 94 aabb. These results are most consistent with ________. A. linkage with 50 percent crossing over B. 100 percent recombination C. sex-linked inheritance with 30 percent crossing over D. linkage with approximately 33.3 map units between the two gene loci E. independent assortment
D. linkage with approximately 33.3 map units between the two gene loci
A linkage group __________. A. can occur only on an autosome B. is a collection of genes that never produce recombinant gametes C. is a chromosomal region in which crossing over cannot occur D. represents some of the genes located on the same chromosome that are physically close together
D. represents some of the genes located on the same chromosome that are physically close together
Which of the following is an example of positive control in operons? A. the regulation of the tryptophan operon by the trp repressor B. attenuation of the trp operon C. regulation of the lac operon by the lac repressor D. the action of the catabolite activator protein (CAP) in the lac operon
D. the action of the catabolite activator protein (CAP) in the lac operon
All of the alleles of the members of a population are known as ___________ A. speciation B. phylogeny C. genetic drift D. the gene pool
D. the gene pool
In a population of cattle, the following color distribution was noted: 36 percent red (RR), 48 percent roan (Rr), and 16 percent white (rr). Which of the following statements is most accurate concerning this population? A. the percentage of red cattle will likely increase in the next generation B. the population has a high coefficient of inbreeding (F) C. the frequency of the r allele is .16 D. the population is in Hardy-Weinberg equilibrium E. the population is not in Hardy-Weinberg equilibrium
D. the population is in Hardy-Weinberg equilibrium
Fitness is a measure of __________. A. the longevity of organisms with a particular genotype B. an organism's increased ability to survive C. an organism's physiological vigor D. the reproductive output of organisms relative to the alternative genotypes
D. the reproductive output of organisms relative to the alternative genotypes
Usually, bacteria only make tryptophan when tryptophan is absent or available in low concentration. However, a particular bacterial mutation makes tryptophan all the time whether or not tryptophan is present. What could explain this phenotype? A. trpA is mutated B. trpE is mutated C. the antiterminator hairpin is unable to form D. the terminator hairpin is unable to form E. trpD is mutated
D. the terminator hairpin is unable to form
Assume that a trait is caused by the homozygous state of a gene that is recessive and autosomal. Nine percent of the individuals in a given population express the phenotype caused by this gene. What percentage of the individuals would be heterozygous for the gene? Assume that the population is in Hardy-Weinberg equilibrium. A. 25% B. 49% C. 21% D. 50% E. 42%
E. 42%
Which of the following is not part of the Y chromosome in humans? A. MSY B. PARS C. Xic D. Xist E. Both Xic and Xist
E. Both Xic and Xist
The F prime plasmid
Functional permease protein could be made from
Part A A couple has a daughter with Turner syndrome, a condition in which only a single copy of the X chromosome is present. This results from nondisjunction, the failure of the X chromosome to segregate properly during meiosis. During which meiotic division, and in which parent, could nondisjunction have occurred to produce a child with this condition? Hint: It may be helpful to sketch a diagram depicting the outcome of nondisjunction in meiosis I and II of both parents to solve this problem. Select all that apply. A. Meiosis I in the mother B. Meiosis II in the mother C. Meiosis I in the father D. Meiosis II in the father Part B A couple has a son with XYY syndrome, a condition in which an extra copy of the Y chromosome is present. This condition also results from nondisjunction. During which meiotic division, and in which parent, could nondisjunction have occurred to produce a child with this condition? Select all that apply. A. Meiosis I in the mother B. Meiosis II in the mother C. Meiosis I in the father D. Meiosis II in the father Part C A couple has a son with Klinefelter syndrome, a condition in which an extra copy of the X chromosome is present. This condition also results from nondisjunction.During which meiotic division, and in which parent, could nondisjunction have occurred to produce a child with this condition? Select all that apply. A. Meiosis I in the mother B. Meiosis II in the mother C. Meiosis I in the father D. Meiosis II in the father Part D If a male with Klinefelter syndrome undergoes spermatogenesis (without nondisjunction), how many chromosomes would be present in the sperm? Select all that apply. A. 22 B. 23 C. 24 D. 45 E. 46 F. 47 Consider the distribution of sex chromosomes that would occur when a male with Klinefelter syndrome (X1X2Y) undergoes spermatogenesis. Which chromosome combinations are possible? Select all that apply. A. X2Y and X1 B. X1X2 and Y C. X1X2Y and O D. X1Y and X2
Part A A. Meiosis I in the mother B. Meiosis II in the mother C. Meiosis I in the father D. Meiosis II in the father Part B D. Meiosis II in the father Part C A. Meiosis I in the mother B. Meiosis II in the mother C. Meiosis I in the father Part D B. 23 C. 24 Part E A. X2Y and X1 B. X1X2 and Y D. X1Y and X2
Colored aleurone in the kernels of corn is due to the dominant allele RR. The recessive allele rr, when homozygous, produces colorless aleurone. The plant color (not kernel color) is controlled by another gene with two alleles, YY and yy. The dominant YY allele results in green color, whereas the homozygous presence of the recessive yy allele causes the plant to appear yellow. In a testcross between a plant of unknown genotype and phenotype and a plant that is homozygous recessive for both traits, the following progeny were obtained. colored, green : 88 colored, yellow : 12 colorless, green : 8 colorless, yellow : 92 Part A: Based on the data, what can you say about the genotype of the unknown plant? A. It was heterozygous for both genes. B. It was heterozygous for one gene and homozygous for the other. C. It was homozygous for both genes. Part B: What is the phenotype of the unknown plant? A. colored, yellow B. colored, green C. colorless, green D. colorless, yellow Part C: What is the precise arrangement of the alleles on the homologs in the unknown plant? A. The genes are unlinked (e.g., on different chromosomes). _________R_______ ________Y_________ _________r________ _________y_________ B. The genes are linked, and the arrangement is not coupled (each homolog has a dominant and a recessive allele). ________R_______y_______ ________r________Y_______ C. The genes are linked, and the arrangement is coupled (one homolog has both dominant alleles; the other homolog has both recessive alleles). ____R__________Y_______ _____r__________y_______
Part A: A. It was heterozygous for both genes. Part B: B. colored, green Part C: C. The genes are linked, and the arrangement is coupled (one homolog has both dominant alleles; the other homolog has both recessive alleles). ____R__________Y_____ _____r__________y_____
The genes for miniature wings (m) and garnet eyes (g) are approximately 8 map units apart on chromosome 1 in Drosophila.Phenotypically wild-type females (m + g / mg +) were mated to miniature-winged males with garnet eyes. Part A: Which of the following phenotypic classes reflect offspring that were generated as a result of a crossover event? Select all that apply. A. miniature wings B. miniature wings, garnet eyes C. wild type D. garnet eyes Part B: If 800 offspring were produced from the cross, in what numbers would you expect the following phenotypes?__wild type : __ miniature wings : __ garnet eyes : __ miniature wings, garnet eyes Enter your answer as the number of flies of each phenotype separated by a colon (example: 100:300:100:300).
Part A: B. miniature wings, garnet eyes C. wild type Part B: 32:368:368:32 Part C:
In the cross shown here, involving two linked genes, ebony (ee) and claret (caca) in Drosophila, where crossing over does not occur in males, offspring were produced in a phenotypic 2+ : 1caca : 1ee ratio. FemaleMaleeca+---------eca+_××eca+---------eca+_e+ca¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯e+ca¯e+ca¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯e+ca¯ These genes are 30 mumu apart on chromosome III. In this problem, you will calculate what crossing over in the female contributes to the phenotypic results. Part A: Which combinations of alleles does the male parent contribute to the offspring? Select all that apply. A. e+ca+ B. e ca C. eca+ D. e+ca Part B: Which combinations of alleles does the female parent contribute to the offspring? Select all that apply. A. e+ca+ B. eca C. eca+ D. e+ca
Part A: C. eca+ D. e+ca Part B: A. e+ca+ B. eca C. eca+ D. e+ca
P In Drosophila, the genes for eye color, wing shape, and wing length are located on chromosome II. Purple eyes (pr), arc bent wings (a), and vestigial wings (vg) are the mutant forms of the wild type traits red eyes, straight wings, and long wings, respectively. You've discovered some data in your genetics laboratory which indicates that the distance between vg and pr is 12.5 m.u., the distance between a and pr is 44.7 m.u., and the distance between a and vg is 32.2 m.u. Part A: From this information, deduce the order of these genes on chromosome II and identify which gene is in the middle. A. pr B. a C. vg D. not enough information to tell Part B: You begin studying heterozygous females (a pr vg/+ + +) and homozygous recessive males as part of your thesis project. Based on the information from Part A, if you set up a cross between the female and male flies, which of the following represents the phenotypic class of offspring resulting from a single crossover event between pr and vg? A. a pr +/+ + vg B. + pr +/a + vg C. + pr vg/a + + D. + + vg/a pr + Part C: If a total of 1250 offspring were obtained from your cross, determine the number of offspring that you would expect to obtain that represent a single crossover event between pr and vg if interference does not occur. Part D: Upon careful examination of the offspring obtained from your cross, it was determined that only 25 offspring were double crossover phenotype -- half of the 50 that was expected. Now, how many offspring that represent a single crossover event between pr and vg are expected, considering that positive interference has occurred?
Part A: C. vg Part B: B. + pr +/a + vg Part C: 106 Part D: 131
A bacterial operon is responsible for the production of biosynthetic enzymes needed to make the hypothetical amino acid tisophane (tis). The operon is regulated by a separate gene, RR. The deletion of RR causes the loss of enzyme synthesis. In the wild-type condition, when tis is present, no enzymes are made; in the absence of tis, the enzymes are made. Mutations in the operator gene (O−O−) result in repression regardless of the presence of tis. Part A: Is the operon under positive or negative control?
Part A: positive
The ____________ is/are arranged sequentially after the promoter.
genes of an operon
A(n) __________ is a specific small molecule that binds to a bacterial regulatory protein and changes its shapes so that it cannot bind to an operator, thus switching an operon on.
inducer
Extracts of ______ cells did not bind the labeled IPTG.
lac l^-
The _________ mutation causes a 10x _________ in repressor protein production, thus facilitating its isolation.
lac l^q; increase
Regulatory proteins bind to the _____________ to control expression of the operon.
operator
A(n) _________ is a specific nucleotide sequence in DNA that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place.
promoter
The material that bound the labeled IPTG was purified and shown to have characteristics of ________.
protein
Describe the role of attenuation in the regulation of tryptophan biosynthesis. Attenuation functions to ___________ the synthesis of tryptophan when it _______ supply. It does so by ________ transcription of the tryptophan operon. The same phenomenon is observed when tryptophan ________ the repressor to shut off transcription of the tryptophan operon.
reduce; is in full; reducing; activates
A(n) ____________ codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes.
regulatory gene
In negative control of gene expression.
removal of the regulatory molecule from DNA stimulates transcription.
A(n) _____________ is a protein that inhibits gene transcription. In prokaryotes, this protein binds to the DNA in or near the promoter.
repressor
In positive control of gene expression.
the regulatory molecule stimulates transcription.
A single E. coli cell contains ________ molecules of the lac repressor.
very few
