Ch. 13, 14, 15

What is the probability that their first child will be an albino?a.0 b.1/4 c.1/2 d.3/4 e.1

b

Which describes the ABO blood group system?a.Incomplete dominance b.Multiple alleles c.Pleiotropy d.Epistasis

b

Which of the following statements is (are) true? a.The closer two genes are on a chromosome, the higher the probability that a crossover will occur between them. b.The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 50%. c.Two of the traits that Mendel studied-seed color and flower color-are linked on the same chromosome. d.Only B and C are correct. e.A, B, and C are correct

b

A Barr body is normally found in the nucleus of which kind of human cell? a.Unfertilized egg cells only b.Sperm cells only c.Somatic cells of a female only d.Somatic cells of a male only e.Both male and female somatic cells

c

A Barr body is normally found in the nucleus of which kind of human cell? a.unfertilized egg cells onlyb.sperm cells only c.somatic cells of a female only d.somatic cells of a male only e.both male and female somatic cells

c

A cross between homozygous purple-flowered and homozygous white-flowered pea plants results in offspring with purple flowers. This demonstrates a.the blending model of genetics. b.true-breeding. c.dominance. d.a dihybrid cross. e.the mistakes made by Mendel

c

A plant with purple flowers is allowed to self-pollinate. Generation after generation, it produces purple flowers. This is an example of a.hybridization. b.incomplete dominance. c.true-breeding. d.the law of segregation. e.polygenetics

c

If a chromosome lacks certain genes, what has most likely occurred? a.disjunction b.an inversion c.a deletion d.a translocation e.a nonduplication

c

If a human interphase nucleus contains three Barr bodies, it can be assumed that the person a.has hemophilia .b.is a male. c.has four X chromosomes. d.has Turner syndrome. e.has Down syndrome

c

Independent assortment of chromosomes occurs. a.The statement is true for mitosis only. b.The statement is true for meiosis I only. c.The statement is true for meiosis II only. d.The statement is true for mitosis and meiosis I. e.The statement is true for mitosis and meiosis II.

b

Male calico cats could be the result of a.sex-linked inheritance. b.nondisjunction, leading to the male calico having two X chromosomes. c.incomplete dominance of multiple alleles. d.recessive alleles retaining their fundamental natures even when expressed. e.a reciprocal translocation.

b

New combinations of linked genes are due to which of the following? a.nondisjunction b.crossing over c.independent assortment d.mixing of sperm and egg e.both A and C

b

The human genome is minimallycontained in which of the following? a.Every human cell b.Each human chromosome c.The entire DNA of a single human d.The entire human populatione.Each human gene

a

The reason that linked genes are inherited together is that a.they are located on the same chromosome. b.the number of genes in a cell is greater than the number of chromosomes. c.chromosomes are unbreakable. d.alleles are paired. e.genes align that way during metaphase I

a

When Thomas Hunt Morgan crossed his red-eyed generation flies to each other, the generation included both red-and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?a.The gene involved is on the X chromosome. b.The gene involved is on the Y chromosome. c.The gene involved is on an autosome. d.Other male-specific factors influence eye color in flies. e.Other female-specific factors influence eye color in flies.

a

The frequency of crossing over between any two linked genes is a.higher if they are recessive. b.different between males and females. c.determined by their relative dominance. d.the same as if they were not linked. e.proportional to the distance between them

e

The frequency of crossing over between any two linked genes will be which of the following? a.Higher if they are recessive b.Dependent on how many alleles there are c.Determined by their relative dominance d.The same as if they were not linked e.Proportional to the distance between them

e

Which of the following is (are) true for alleles? a.They can be identical or different for any given gene in a somatic cell. b.They can be dominant or recessive. c.They can represent alternative forms of a gene. d.Only A and B are correct. e.A, B, and C are correct

e

hich of the following is false, regarding the law of segregation? a.It states that each of two alleles for a given trait segregate into different gametes. b.It can be explained by the segregation of homologous chromosomes during meiosis. c.It can account for the 3:1 ratio seen in the F2 generation of Mendel's crosses. d.It can be used to predict the likelihood of transmission of certain genetic diseases within families. e.It is a method that can be used to determine the number of chromosomes in a plant

e

If a human interphase nucleus of a person contains three Barr bodies, it can be assumed that the person a.has hemophilia. b.is a male. c.has four X chromosomes. d.has Turner syndrome. e.has Down syndrome.

c

If nondisjunction occurs in meiosis II during gametogenesis, what will be the result at the completion of meiosis? a.All the gametes will be diploid. b.Half of the gametes will be n+ 1, and half will be n-1. c.1/4 of the gametes will be n+ 1, one will be n-1, and two will be n. d.There will be three extra gametes. e.Two of the four gametes will be haploid, and two will be diploid.

c

If nondisjunction occurs in meiosis II during gametogenesis, what will be the result at the completion of meiosis? a.All the gametes will be diploid. b.Two gametes will be n + 1, and two will be n - 1. c.One gamete will be n + 1, one will be n - 1, and two will be n. d.There will be three extra gametes. e.Two of the four gametes will be haploid, and two will be diploid

c

The karyotype shown below is associated with which of the following genetic disorders? a.Turner syndrome b.Down syndrome c.Klinefelter syndromed.hemophilia e.male-pattern baldness

c

What is the mechanism for the production of genetic recombinants? a.X inactivation b.methylation of cytosine c.crossing over and independent assortment d.nondisjunction e.deletions and duplications during meiosis

c

Which of the following is a possible phenotype for the father? a.A b.O c.B d.AB e.impossible to determine

c

cross between homozygous purple-flowered and homozygous white-flowered pea plants results in offspring with purple flowers. This demonstrates a.the blending model of genetics. b.true-breeding. c.dominance. d.a dihybrid cross. e.the mistakes made by Mendel.

c

n animals, meiosis results in gametes, and fertilization results in a.spores. b.gametophytes. c.zygotes. d.sporophytes. e.clones.

c

A man who carries an X-linked allele will pass it on to a.all of his daughters. b.half of his daughters. c.all of his sons. d.half of his sons. e.all of his children

a

Independent assortment of chromosomes is a result of a.the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I. b.the random nature of the fertilization of ova by sperm. c.the random distribution of the sister chromatids to the two daughter cells during anaphase II. d.the relatively small degree of homology shared by the X and Y chromosomes. e.All of the above

a

Males are more often affected by sex-linked traits than females because a.males are hemizygous for the X chromosome. b.male hormones such as testosterone often exacerbate the effects of mutations on the X chromosome. c.female hormones such as estrogen often compensate for the effects of mutations on the X. d.X chromosomes in males generally have more mutations than X chromosomes in females. e.mutations on the Y chromosome often exacerbate the effects of X-linked mutations.

a

Of the following human trisomies, the one that generally has the most severe impact on the health of the individual is a.trisomy 21. b.Klinefelter syndrome (XXY). c.trisomy X. d.XYY. e.All of the above have equal impact.

a

Which of the following terms best describes when the phenotype of the heterozygote differs from the phenotypes of both homozygotes? a.Incomplete dominance b.Multiple alleles c.Pleiotropy d.Epistasis

a

33. If the intermediate F1 progeny were allowed to self-pollinate, and the F2 progeny were also intermediate in size, but following a normal distribution, this would suggest a.incomplete dominance. b.polygenic inheritance. c.complete dominance. d.a strong environmental influence. e.codominance.____ 34. If the intermediate F1 progeny were allowed to self-pollinate, and 25% of the F2 progeny were tall, 50% were intermediate in size, and 25% were short, this would suggest a.incomplete dominance. b.polygenic inheritance. c.complete dominance. d.pleiotropy. e.multifactorial inheritance

a, c

A cross between homozygous purple-flowered and homozygous white-flowered pea plants results inoffspring with purple flowers. This demonstrates a.the blending model of genetics. b.true-breeding. c.dominance. d.a dihybrid cross. e.the mistakes made by Mendel.

c

A human individual is phenotypically female, but her interphase somatic nuclei do not show the presence of Barr bodies. Which of the following statements concerning her is probably true? a.She has Klinefelter syndrome. b.She has an extra X chromosome. c.She has Turner syndrome. d.She has the normal number of sex chromosomes. e.She has two Y chromosomes.

c

A man with Klinefelter syndrome (47, XXY) is expected to have any of the following EXCEPT a.lower sperm count. b.possible breast enlargement. c.increased testosterone. d.long limbs. e.female body characteristics.

c

CROSS I. Purebred lines of wild-type fruit flies (gray body and normal wings) are mated to flies with black bodies and vestigial wings.F1 offspring all have a normal phenotype.CROSS II. F1 flies are crossed with flies recessive for both traits (a testcross).Resulting OffspringNormalPercentageGray body; normal wings57525.1Black body; vestigial wings57124.9Black body; normal wings57725.2Gray body; vestigial wings56824.8KEY:A. CROSS I results give evidence supporting the statement.B. CROSS I results give evidence against the statement.C. CROSS II results give evidence supporting the statement.D. CROSS II results give evidence against the statement.E. Neither CROSS I nor CROSS II results support the statement.____ 83. Vestigial wings are a recessive trait. a.A b.B c.C d.D e.E____ 84. The genes for body color and wing shape are linked. a.A b.B c.C d.D e.E 85. An F1 cross should produce flies that will fall into a Mendelian 9:3:3:1 ratio. a.A b.B c.C d.D e.E____ 86. There are 25 centimorgans (map units) between the genes for body color and wing shape. a.A b.B c.C d.D e.E

a, c,c,d

A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color-blind marries a color-blind male. What is the probability that a son of this couple will be color-blind? a.0 b.1/4 c.1/2 d.3/4 e.1

b

Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. The relationship between genes S and N is an example of a.incomplete dominance. b.epistasis. c.complete dominance. d.pleiotropy. e.codominance

b

Homologous chromosomes synapse and crossing over occurs. a.The statement is true for mitosis only. b.The statement is true for meiosis I only. c.The statement is true for meiosis II only. d.The statementis true for mitosis and meiosis I. e.The statement is true for mitosis and meiosis II.

b

If their first two children have normal pigmentation, what is the probability that their third child will be an albino? a.0 b.1/4 c.1/2 d.3/4 e.1

b

P = purple, pp = white. The offspring of a cross between two heterozygous purple-flowering plants (Pp×Pp)results in a.all purple-flowered plants. b.purple-flowered plants and white-flowered plants. c.two types of white-flowered plants: PP and Pp. d.all white-flowered plants. e.all pink-flowered plants.

b

What is genetic cross between an individual showing a dominant phenotype (but of unknown genotype) and a homozygous recessive individual called? a.a self-cross b.a testcross c.a hybrid cross d.an F1 cross e.a dihybrid cross

b

A couple has three children, all of whom have brown eyes and blond hair. Both parents are homozygous for brown eyes (BB) but one is a blond (rr) and the other is a redhead (Rr). What is the probability that their next child will be a brown-eyed redhead? a.1/16 b.1/8 c.1/4 d.1/2 e.1

d

A nonreciprocal crossover causes which of the following products? a.deletion b.duplication c.nondisjunction d.A and B e.B and C

d

After telophase I of meiosis, the chromosomal makeup of each daughter cell is a.diploid, and the chromosomes are each composed of a single chromatid. b.diploid, and the chromosomes are each composed of two chromatids. c.haploid, and the chromosomes are each composed of a single chromatid. d.haploid, and the chromosomes are each composed of two chromatids. e.tetraploid, and the chromosomes are each composed of two chromatids.

d

Black fur in mice (B) is dominant to brown fur (b) Short tails (T) are dominant to long tails (t). What fraction of the progeny of the cross BbTt × BBtt will have black fur and long tails? a.1/16 b.3/16 c.3/8 d.1/2 e.9/16__

d

Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of the cross BbTtBBttwill have black fur and long tails? a.1/16 b.3/16 c.3/8 d.1/2 e.9/16

d

Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division? a.Prophase I of meiosis b.Prophase II of meiosis c.Metaphase I of meiosis d.Anaphase I of meiosis e.Anaphase of mitosis

d

One possible result of chromosomal breakage can be that a fragment reattaches to the original chromosome in a reverse orientation. This is called a.disjunction. b.translocation. c.deletion. d.inversion. e.aneuploidy.

d

One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. This is called a (an) a.deletion. b.disjunction .c.inversion. d.translocation. e.duplication.

d

Pea plants were particularly well suited for use in Mendel's breeding experiments for all of the following reasons except that a.peas show easily observed variations in a number of characters, such as pea shape and flower color. b.it is possible to completely control matings between different pea plants. c.it is possible to obtain large numbers of progeny from any given cross. d.peas have an unusually long generation time. e.many of the observable characters that vary in pea plants are controlled by single genes.

d

There is good evidence for linkage when a.two genes occur together in the same gamete. b.a gene is associated with a specific phenotype. c.two genes work together to control a specific characteristic. d.genes do not segregate independently during meiosis. e.two characteristics are caused by a single gene

d

What do all human males inherit from their mother?a.mitochondrial DNA b.an X chromosome c.the SRY gene d.A and B only e.A, B, and C____

d

Which of the following statements about Mendel's breeding experiments is correct? a.None of the parental (P) plants were true-breeding. b.All of the F2 progeny showed a phenotype that was intermediate between the two parental (P) phenotypes. c.Half of the F1 progeny had the same phenotype as one of the parental (P) plants, and the other half had the same phenotype as the other parent. d.All of the F1 progeny resembled one of the parental (P) plants, but only some of the F2 progeny did. e.none of the above

d

Which of these statements is false? a.In humans, each of the 22 maternal autosomes has a homologous paternal chromosome. b.In humans, the 23rd pair, the sex chromosomes, determines whether the person is female (XX) or male (XY). c.Single, haploid (n) sets of chromosomes in ovum and sperm unite during fertilization, forming a diploid (2n), single-celled zygote. d.At sexual maturity, ovaries and testes produce diploid gametes by meiosis. e.Sexual life cycles differ with respect to the relative timing of meiosis and fertilization

d

A 0.1% frequency of recombination is observed a.only in sex chromosomes. b.only on genetic maps of viral chromosomes. c.on unlinked chromosomes. d.in any two genes on different chromosomes. e.in genes located very close to one another on the same chromosome.

e

Chromatids are separated from each other. a.The statement is true for mitosis only. b.The statement is true for meiosis I only. c.The statement is true for meiosis II only. d.The statement is true for mitosis and meiosis I. e.The statement is true for mitosis and meiosis II.

e

Chromosomes and genes share all of the following characteristics except that a.they are both present in pairs in all diploid cells. b.they both undergo segregation during meiosis. c.their copy numbers in the cell decrease after meiosis, and increase during fertilization. d.they are both copied during the S phase of the cell cycle. e.they both pair up with their homologues during prophase of mitosis

e

In snapdragons, heterozygotes for one of the genes have pink flowers, whereas homozygotes have red or white flowers. When plants with red flowers are crossed with plants with white flowers, what proportion of the offspring will have pink flowers? a.0% b.25% c.50% d.75% e.100%

e

People with sickle-cell trait a.are heterozygous for the sickle-cell allele. b.are usually healthy. c.have increased resistance to malaria. d.produce normal and abnormal hemoglobin. e.all of the above

e