Chapter 14 Study Guide

21) Which of the boxes marked 1-4 correspond to plants that will be true-breeding? A) 1 and 4 only B) 2 and 3 only C) 1, 2, 3, and 4 D) 1 only

A) 1 and 4 only

41) A man has extra digits (six fingers on each hand and six toes on each foot). His wife and their daughter have a normal number of digits. Having extra digits is a dominant trait. The couple's second child has extra digits. What is the probability that their next (third) child will have extra digits? A) 1/2 B) 1/16 C) 1/8 D) 3/4

A) 1/2

78) In rabbits, the homozygous CC is normal, Cc results in deformed legs, and cc results in very short legs. The genotype BB produces black fur, Bb brown fur, and bb white fur. If a cross is made between brown rabbits with deformed legs and white rabbits with deformed legs, what percentage of the offspring would be expected to have deformed legs and white fur? A) 25% B) 33% C) 100% D) 50%

A) 25%

79) In humans, ABO blood types refer to glycoproteins in the membranes of red blood cells. There are three alleles for this autosomal gene: IA, IB, and i. The IA allele codes for the A glycoprotein, The IB allele codes for the B glycoprotein, and the i allele doesn't code for any membrane glycoprotein. IA and IB are codominant, and i is recessive to both IA and IB. People with type A blood have the genotypes IAIA or IAi, people with type B blood are IBIB or IBi, people with type AB blood are IAIB, and people with type O blood are ii. If a woman with type AB blood marries a man with type O blood, which of the following blood types could their children possibly have? A) A and B. B) AB and O. C) A, B, and O. D) A, B, AB, and O.

A) A and B.

27) A black guinea pig crossed with an albino guinea pig produced twelve black offspring. When the albino was crossed with a second black animal, six blacks and six albinos were obtained. What is the best explanation for this genetic situation? A) Albino is recessive; black is dominant. B) Albino is dominant; black is incompletely dominant. C) Albino and black are codominant. D) Albino is recessive; black is codominant.

A) Albino is recessive; black is dominant.

Drosophila (fruit flies) usually have long wings (+) but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg). If a homozygous bent wing fly is mated with a homozygous vestigial wing fly, which of the following offspring would you expect? A) All +bt +vg heterozygotes B) 1/2 bent and 1/2 vestigial flies C) All homozygous + flies D) 3/4 bent to 1/4 vestigial ratio E) 1/2 bent and vestigial to 1/2 normal

A) All +bt +vg heterozygotes

If both children are of blood group MM, which of the following is possible? A) Each parent is either M or MN. B) Each parent must be type M. C) Both children are heterozygous for this gene. D) Neither parent can have the N allele. E) The MN blood group is recessive to the ABO blood group.

A) Each parent is either M or MN.

49) Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following? A) Environmental factors such as soil pH. B) The allele for blue hydrangea being completely dominant. C) The alleles being codominant. D) The fact that a mutation has occurred. E) Acknowledging that multiple alleles are involved.

A) Environmental factors such as soil pH.

10) A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism? A) HT. B) Hh. C) HhTt. D) T. E) tt.

A) HT.

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) Incomplete dominance

An ideal procedure for fetal testing in humans would have which of the following features? A) Lowest risk procedure that would provide the most reliable information B) The procedure that can test for the greatest number of traits at once C) A procedure that provides a 3D image of the fetus D) The procedure that can be performed at the earliest time in the pregnancy E) A procedure that could test for the carrier status of the fetus

A) Lowest risk procedure that would provide the most reliable information

89) Which of the following statements is a correct explanation for the observation that all offspring exhibit a phenotype for a particular trait that appears to be a blend of the two parental varieties? A) Neither of the parental genes is dominate over the other. B) The genes for the trait are dominant in both of the parents. C) The genes are linked and do not separate during meiosis. D) The genes for the trait are recessive in both of the parents.

A) Neither of the parental genes is dominate over the other.

A pedigree analysis for a given disorderʹs occurrence in a family shows that, although both parents of an affected child are normal, each of the parents has had affected relatives with the same condition. The disorder is then which of the following? A) Recessive B) Dominant C) Incompletely dominant D) Maternally inherited E) A new mutation

A) Recessive

9) Which of the following statements about independent assortment and segregation is correct? A) The law of independent assortment requires describing two or more genes relative to one another. B) The law of segregation requires describing two or more genes relative to one another. C) The law of independent assortment is accounted for by observations of prophase I. D) The law of segregation is accounted for by anaphase of mitosis.

A) The law of independent assortment requires describing two or more genes relative to one another.

A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce A) all sharp-spined progeny. B) 50% sharp-spined, 50% dull-spined progeny. C) 25% sharp-spined, 50% dull-spined, 25% spineless progeny D) all spineless progeny. E) It is impossible to determine the phenotypes of the progeny.

A) all sharp-spined progeny.

When a disease is said to have a multifactorial basis, it means that A) both genetic and environmental factors contribute to the disease. B) it is caused by a gene with a large number of alleles. C) it affects a large number of people. D) it has many different symptoms. E) it tends to skip a generation.

A) both genetic and environmental factors contribute to the disease.

The F1 offspring of Mendelʹs classic pea cross always looked like one of the two parental varieties because A) one phenotype was completely dominant over another. B) each allele affected phenotypic expression. C) the traits blended together during fertilization. D) no genes interacted to produce the parental phenotype. E) different genes interacted to produce the parental phenotype.

A) one phenotype was completely dominant over another.

28) Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. (a) What is the most probable genotype of each parent? (b) Based on your answer in (a) above, what genotypic and phenotypic ratios are expected in these progeny? (Assume the following symbols: G = gray and g = white.) A) (a) GG × gg; (b) genotypic = 3:1, phenotypic = 1:2:1. B) (a) Gg × Gg; (b) genotypic = 1:2:1, phenotypic = 3:1. C) (a) GG × Gg; (b) genotypic = 1:2:1, phenotypic = 2:1. D) (a) gg × Gg; (b) genotypic = 1:2, phenotypic = 3:1.

B) (a) Gg × Gg; (b) genotypic = 1:2:1, phenotypic = 3:1.

90) The pattern of inheritance (monohybrid, dihybrid, sex-linked, and genes linked on the same chromosomes) can be predicted from data if one is given the parent or offspring genotypes or phenotypes. Two organisms, with genotypes BbDD and BBDd, are mated. Assuming independent assortment of the B/b and D/d genes, determine the genotypic ratios in offspring that would occur. A) 1/2 BBDD 1/2 bbdd. B) 1/4 BBDD 1/4 BbDD 1/4 BBDd 1/4 BbDd. C) 9/16 BBDD 3/16 BbDD 3/16 BBDd 1/16 bbdd. D) 1/4 BBDD 1/2 BbDd 1/4 bbdd.

B) 1/4 BBDD 1/4 BbDD 1/4 BBDd 1/4 BbDd.

45) Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently. If 1,000 F2 offspring resulted from the cross, approximately how many of them would you expect to have red, terminal flowers? A) 65. B) 190. C) 250. D) 565. E) 750.

B) 190.

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE? A) 4 B) 8 C) 16 D) 32 E) 64

B) 8

56) The relationship between genes S and N is an example of A) Incomplete dominance. B) Epistasis. C) Complete dominance. D) Pleiotropy. E) Codominance.

B) Epistasis.

Which describes the ABO blood group system? A) Incomplete dominance B) Multiple alleles C) Pleiotropy D) Epistasis

B) Multiple alleles

8) Mendel continued some of his experiments into the F2 or F3 generation to _____. A) Obtain a larger number of offspring on which to base statistics. B) Observe whether or not a recessive trait would reappear. C) Observe whether or not the dominant trait would reappear. D) Distinguish which alleles were segregating.

B) Observe whether or not a recessive trait would reappear.

One of two major forms of a human condition called neurofibromatosis (NF 1) is inherited as a dominant, although it may be either mildly to very severely expressed. If a young child is the first in her family to be diagnosed, which of the following is the best explanation? A) The mother carries the gene but does not express it at all. B) One of the parents has very mild expression of the gene. C) The condition skipped a generation in the family. D) The child has a different allele of the gene than the parents.

B) One of the parents has very mild expression of the gene.

46) In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red : 2 roan : 1 white? A) Red × white. B) Roan × roan. C) White × roan. D) Red × roan. E) The answer cannot be determined from the information provided.

B) Roan × roan.

Two characters that appear in a 9:3:3:1 ratio in the F2 generation should have which of the following properties? A) Each of the traits is controlled by single genes. B) The genes controlling the characters obey the law of independent assortment. C) Each of the genes controlling the characters has two alleles. D) Four genes are involved. E) Sixteen different phenotypes are possible.

B) The genes controlling the characters obey the law of independent assortment.

34) Which of the following is the best statement of the use of the addition rule of probability? A) The probability that two or more independent events will both occur. B) The probability that either one of two independent events will occur. C) The probability of producing two or more heterozygous offspring. D) The likelihood that a trait is due to two or more meiotic events.

B) The probability that either one of two independent events will occur.

94) A scientist discovers a DNA-based test for the allele of a particular gene. This and only this allele, if homozygous, produces an effect that results in death at or about the time of birth. Of the following, which is the best use of this discovery? A) To screen all newborns of an at-risk population. B) To design a test for identifying heterozygous carriers of the allele. C) To introduce a normal allele into deficient newborns. D) To follow the segregation of the allele during meiosis. E) To test school-age children for the disorder.

B) To design a test for identifying heterozygous carriers of the allele.

What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants? A) There is considerable genetic variation in garden peas. B) Traits are inherited in discrete units, and are not the results of ʺblending.ʺ C) Recessive genes occur more frequently in the F1 than do dominant ones. D) Genes are composed of DNA. E) An organism that is homozygous for many recessive traits is at a disadvantage.

B) Traits are inherited in discrete units, and are not the results of ʺblending.ʺ

It was important that Mendel examined not just the F1 generation in his breeding experiments, but the F2 generation as well, because A) he obtained very few F1 progeny, making statistical analysis difficult. B) parental traits that were not observed in the F1 reappeared in the F2. C) analysis of the F1 progeny would have allowed him to discover the law of segregation, but not the law of independent assortment. D) the dominant phenotypes were visible in the F2 generation, but not in the F1. E) many of the F1 progeny died.

B) parental traits that were not observed in the F1 reappeared in the F2.

52) Skin color in a certain species of fish is inherited via a single gene with four different alleles. One fish of this type has alleles 1 and 3 (S1S3) and its mate has alleles 2 and 4 (S2S4). If each allele confers a unit of color darkness such that S1 has one unit, S2 has two units, and so on, then what proportion of their offspring would be expected to have five units of color? A) 1/4 B) 1/8 C) 1/2 D) 0

C) 1/2

Huntingtonʹs disease is a dominant condition with late age of onset in humans. If one parent has the disease, what is the probability that his or her child will have the disease? A) 1 B) 3/4 C) 1/2 D) 1/4 E) 0

C) 1/2

A woman has six sons. The chance that her next child will be a daughter is A) 1. B) 0. C) 1/2. D) 1/6. E) 5/6.

C) 1/2.

25) Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation, but both have one parent who is albino (without melanin pigmentation). What is the probability that their first child will be an albino? A) 0 B) 1/2 C) 1/4 D) 1

C) 1/4

Cystic fibrosis (CF) is a Mendelian disorder in the human population that is inherited as a recessive. Two normal parents have two children with CF. The probability of their next child being normal for this characteristic is which of the following? A) 0 B) 1/2 C) 1/4 D) 3/4 E) 1/8

C) 1/4

43) Assuming independent assortment for all gene pairs, what is the probability that the following parents, AABbCc × AaBbCc, will produce an AaBbCc offspring? A) 1/2 B) 1/16 C) 1/8 D) 3/4

C) 1/8

29) When Mendel crossed yellow-seeded and green-seeded pea plants, all the offspring were yellow seeded. When he took these F1 yellow-seeded plants and crossed them to green-seeded plants, what genotypic ratio was expected? A) 1:2:1. B) 3:1. C) 1:1. D) 1:1:1:1.

C) 1:1.

20) Which of the boxes marked 1-4 correspond to plants with a heterozygous genotype? A) 1 B) 1, 2, and 3 C) 2 and 3 D) 2, 3, and 4

C) 2 and 3

36) Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently. Among the F2 offspring, what is the probability of plants with white axial flowers? A) 9/16 B) 1/16 C) 3/16 D) 1/4

C) 3/16

33) Given the parents AABBCc × AabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent with genotype AABBCc? A) 1/4. B) 1/8. C) 3/4. D) 3/8. E) 1.

C) 3/4.

Skin color in a certain species of fish is inherited via a single gene with four different alleles. How many different types of gametes would be possible in this system? A) 1 B) 2 C) 4 D) 8 E) 16

C) 4

What is the likelihood that the progeny of IV-3 and IV-4 will have wooly hair? A) 0% B) 25% C) 50% D) 75% E) 100%

C) 50%

When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype? A) 0% B) 25% C) 50% D) 75% E) 100%

C) 50%

2) What is the difference between a monohybrid cross and a dihybrid cross? A) A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents. B) A monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny. C) A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied. D) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. E) A monohybrid cross results in a 9:3:3:1 ratio whereas a dihybrid cross gives a 3:1 ratio.

C) A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied.

Mendelʹs second law of independent assortment has its basis in which of the following events of meiosis I? A) Synapsis of homologous chromosomes B) Crossing over C) Alignment of tetrads at the equator D) Separation of homologs at anaphase E) Separation of cells at telophase

C) Alignment of tetrads at the equator

80) An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable biochemically in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient? A) Karyotyping of the woman's somatic cells. B) X-ray. C) Amniocentesis or CVS. D) Blood transfusion.

C) Amniocentesis or CVS.

Which of the following is a possible phenotype for the father? A) A negative B) O negative C) B positive D) AB negative E) Impossible to determine

C) B positive

26) Albinism is an autosomal (not sex-linked) recessive trait. A man and woman are both of normal pigmentation and have one child out of three who is albino (without melanin pigmentation). What are the genotypes of the albino's parents? A) One parent must be homozygous for the recessive allele; the other parent can be homozygous dominant, homozygous recessive, or heterozygous. B) One parent must be heterozygous; the other parent can be homozygous dominant, homozygous recessive, or heterozygous. C) Both parents must be heterozygous. D) One parent must be homozygous dominant; the other parent must be heterozygous.

C) Both parents must be heterozygous.

35) Which of the following calculations require that you utilize the addition rule? A) Calculate the probability of black offspring from the cross AaBb × AaBb, where B is the symbol for black. B) Calculate the probability of children with both cystic fibrosis and polydactyly when parents are each heterozygous for both genes. C) Calculate the probability of each of four children having cystic fibrosis if the parents are both heterozygous. D) Calculate the probability of a child having either sickle-cell anemia or cystic fibrosis if parents are each heterozygous for both.

C) Calculate the probability of each of four children having cystic fibrosis if the parents are both heterozygous.

81) In some parts of Africa, the frequency of heterozygosity for the sickle-cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following? A) Mendel's law of independent assortment. B) Mendel's law of segregation. C) Darwin's explanation of natural selection. D) The malarial parasite changing the allele.

C) Darwin's explanation of natural selection.

95) The frequency of heterozygosity for the sickle cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following? A) Mendel's law of independent assortment. B) Mendel's law of segregation. C) Darwin's explanation of natural selection. D) Darwin's observations of competition. E) The malarial parasite changing the allele.

C) Darwin's explanation of natural selection.

50) Which of the following provides an example of epistasis? A) Recessive genotypes for each of two genes (aabb) results in an albino corn snake. B) The allele b17 produces a dominant phenotype, although b1 through b16 do not. C) In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing. D) In Drosophila (fruit flies), white eyes can be due to an X-linked gene or to a combination of other genes.

C) In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing.

77) Marfan syndrome in humans is caused by an abnormality of the connective tissue protein fibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the spine, sometimes weakened arterial walls, and sometimes ocular problems, such as lens dislocation. Which of the following would you conclude about Marfan syndrome from this information? A) It is recessive. B) It is dominant. C) It is pleiotropic. D) It is epistatic.

C) It is pleiotropic.

Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this? A) Incomplete dominance B) Multiple alleles C) Pleiotropy D) Epistasis

C) Pleiotropy

Which describes the ability of a single gene to have multiple phenotypic effects? A) Incomplete dominance B) Multiple alleles C) Pleiotropy D) Epistasis

C) Pleiotropy

47) Which of the following describes the ability of a single allele to have multiple phenotypic effects? A) Incomplete dominance. B) Multiple alleles. C) Pleiotropy. D) Epistasis.

C) Pleiotropy.

24) Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6022 yellow and 2001 green (8023 total). The allele for green seeds has what relationship to the allele for yellow seeds? A) Dominant. B) Incomplete dominant. C) Recessive. D) Codominant.

C) Recessive.

Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize a particular amino acid. This amino acid is not otherwise produced by humans. Therefore the most efficient and effective treatment is which of the following? A) Feed them the substrate that can be metabolized into this amino acid. B) Transfuse the patients with blood from unaffected donors. C) Regulate the diet of the affected persons to severely limit the uptake of the amino acid. D) Feed the patients the missing enzymes in a regular cycle, i.e., twice per week.

C) Regulate the diet of the affected persons to severely limit the uptake of the amino acid.

83) Hutchinson-Gilford progeria is an exceedingly rare human genetic disorder in which there is very early senility, and death, usually of coronary artery disease, at an average age of approximately 13. Patients, who look very old even as children, do not live to reproduce. Which of the following represents the most likely assumption? A) All cases must occur in relatives; therefore, there must be only one mutant allele. B) Successive generations of a family will continue to have more and more cases over time. C) The disorder may be due to mutation in a single protein-coding gene. D) Each patient will have had at least one affected family member in a previous generation. E) The disease is autosomal dominant.

C) The disorder may be due to mutation in a single protein-coding gene.

11) Mendel accounted for the observation that traits that had disappeared in the F1 generation reappeared in the F2 generation by proposing that _____. A) New mutations were frequently generated in the F2 progeny, "reinventing" traits that had been lost in the F1. B) The mechanism controlling the appearance of traits was different between the F1 and the F2 plants. C) Traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1. D) Members of the F1 generation had only one allele for each trait, but members of the F2 had two alleles for each trait.

C) Traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1.

37) Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that: A) New mutations were frequently generated in the F2 progeny, "reinventing" traits that had been lost in the F1. B) The mechanism controlling the appearance of traits was different between the F1 and the F2 plants. C) Traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1. D) The traits were lost in the F1 due to blending of the parental traits. E) Members of the F1 generation had only one allele for each character, but members of the F2 had two alleles for each character.

C) Traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1.

55) In one type cross of black × black, the results were as follows: 9/16 black 4/16 yellow 3/16 brown The genotype aabb must result in which of the following? A) Black. B) Brown. C) Yellow. D) A lethal result.

C) Yellow.

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) dominance.

A 1:2:1 phenotypic ratio in the F2 generation of a monohybrid cross is a sign of A) complete dominance. B) multiple alleles. C) incomplete dominance. D) polygenic inheritance. E) pleiotropy.

C) incomplete dominance.

85) What is the genotype of individual II-5? A) WW. B) Ww. C) ww. D) WW or ww. E) ww or Ww.

C) ww.

Two blue budgies were crossed. Over the years, they produced 22 offspring, 5 of which were white. What are the most likely genotypes for the two blue budgies? A) yyBB and yyBB B) yyBB and yyBb C) yyBb and yyBb D) yyBB and yybb E) yyBb and yybb

C) yyBb and yyBb

30) 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) 1/2.

44) Suppose two AaBbCc individuals are mated. Assuming that the genes are not linked, what fraction of the offspring are expected to be homozygous recessive for the three traits? A) 1/4 B) 1/8 C) 1/16 D) 1/64

D) 1/64

42) Phenylketonuria is an inherited disease caused by a recessive autosomal allele. If a woman and her husband are both carriers, what is the probability that their first child will be a phenotypically normal girl? A) 1/4 B) 1/16 C) 3/16 D) 3/8

D) 3/8

39) The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following? A) None of the traits obeyed the law of segregation. B) The diploid number of chromosomes in the pea plants was 7. C) All of the genes controlling the traits were located on the same chromosome. D) All of the genes controlling the traits behaved as if they were on different chromosomes. E) The formation of gametes in plants occurs by mitosis only.

D) All of the genes controlling the traits behaved as if they were on different chromosomes.

The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following? A) None of the traits obeyed the law of segregation. B) The diploid number of chromosomes in the pea plants was 7. C) All of the genes controlling the traits were located on the same chromosome. D) All of the genes controlling the traits behaved as if they were on different chromosomes.

D) All of the genes controlling the traits behaved as if they were on different chromosomes.

Mendelʹs 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) Anaphase I of meiosis

88) From this pedigree, this trait seems to be inherited _____. A) From mothers. B) As an autosomal recessive. C) As a result of epistasis. D) As an autosomal dominant.

D) As an autosomal dominant.

A blue budgie is crossed with a white budgie. Which of the following results is not possible? A) Green offspring only B) Yellow offspring only C) Blue offspring only D) Green and yellow offspring E) a 9:3:3:1 ratio

D) Green and yellow offspring

The flower color trait in radishes is an example of which of the following? A) A multiple allelic system B) Sex linkage C) Codominance D) Incomplete dominance E) Epistasis

D) Incomplete dominance

51) Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following? A) A multiple allelic system. B) Sex linkage. C) Codominance. D) Incomplete dominance.

D) Incomplete dominance.

1) 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 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) Peas have an unusually long generation time.

If true-breeding red long radishes are crossed with true breeding white oval radishes, the F 1 will be expected to be which of the following? A) Red and long B) Red and oval C) White and long D) Purple and long E) Purple and oval

D) Purple and long

12) Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. This suggests: A) That the parents were true-breeding for contrasting traits. B) Incomplete dominance. C) That a blending of traits has occurred. D) That the parents were both heterozygous. E) That each offspring has the same alleles.

D) That the parents were both heterozygous.

Most genes have many more than two alleles. However, which of the following is also true? A) At least one allele for a gene always produces a dominant phenotype. B) Most of the alleles will never be found in a live-born organism. C) All of the alleles but one will produce harmful effects if homozygous. D) There may still be only two phenotypes for the trait. E) More than two alleles in a genotype is lethal.

D) There may still be only two phenotypes for the trait.

Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower color is dominant to white (r). The heterozygous condition results in pink (Rr) flower color. A dwarf, red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F 1 individuals? A) ttRr-dwarf and pink B) ttrr-dwarf and white C) TtRr-tall and red D) TtRr-tall and pink E) TTRR-tall and red

D) TtRr-tall and pink

5) The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason? A) segregation of maternal and paternal alleles B) recurrent mutations forming new alleles C) crossing over during prophase I D) different possible alignments of chromosomes E) the tendency for dominant alleles to segregate together

D) different possible alignments of chromosomes

31) In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short? A) 1. B) 1/2. C) 1/4. D) 1/6. E) 0.

E) 0.

What is the probability that individual III-1 is Ww? A) 3/4 B) 1/4 C) 2/4 D) 2/3 E) 1

E) 1

19) Which of the boxes marked 1-4 correspond to plants with dark leaves? A) 1 only. B) 1 and 2. C) 2 and 3. D) 4 only. E) 1, 2, and 3.

E) 1, 2, and 3.

32) In a cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC? A) 1/4. B) 1/8. C) 1/16. D) 1/32. E) 1/64.

E) 1/64.

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) 100%

In the F2 generation of the above cross, which of the following phenotypic ratios would be expected? A) 9:3:3:1 B) 9:4:3 C) 1:1:1:1 D) 1:1:1:1:1:1 E) 6:3:3:2:1:1

E) 6:3:3:2:1:1

If doubly heterozygous SsNn cactuses were allowed to self-pollinate, the F2 would segregate in which of the following ratios? A) 3 sharp-spined : 1 spineless B) 1 sharp-spined : 2 dull-spined : 1 spineless C) 1 sharp spined : 1 dull-spined : 1 spineless D) 1 sharp-spined : 1 dull-spined E) 9 sharp-spined : 3 dull-spined : 4 spineless

E) 9 sharp-spined : 3 dull-spined : 4 spineless

91) 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) All of the above

40) Mendel was able to draw his ideas of segregation and independent assortment because of the influence of which of the following? A) His reading and discussion of Darwin's Origin of Species. B) The understanding of particulate inheritance he learned from renowned scientists of his time. C) His discussions of heredity with his colleagues at major universities. D) His reading of the scientific literature current in the field. E) His experiments with the breeding of plants such as peas.

E) His experiments with the breeding of plants such as peas.

38) Which of the following about the law of segregation is false? 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) It is a method that can be used to determine the number of chromosomes in a plant.

48) Which of the following is an example of polygenic inheritance? A) Pink flowers in snapdragons. B) The ABO blood groups in humans. C) Huntington's disease in humans. D) White and purple flower color in peas. E) Skin pigmentation in humans.

E) Skin pigmentation in humans.