[AP Biology] Chapter 14

Which of the plants will be true-breeding? A) 1 and 4 B) 2 and 3 C) 1—4 D) 1 only E) None

A) 1 and 4

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

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. 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.

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

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

A pedigree analysis for a given disorder's 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

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether cacti have spines. Homozygous recessive nn cactuses have no spines at all. 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.

A tall plant is crossed with a short plant, and the progeny are all intermediate in size between the two parental plantsIf 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) incomplete dominance.

The F1 offspring of Mendel's classic pea cross always looked like one of the two parental varieties because A) one allele 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 allele was completely dominant over another.

4) The F1 offspring of Mendel's 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.

What are Punnett squares used for? A) predicting the result of genetic crosses between organisms of known genotypes B) determining the DNA sequence of a given gene C) identifying the gene locus where allelic variations are possible D) testing for the presence of the recessive allele E) more than one of the above

A) predicting the result of genetic crosses between organisms of known genotypes

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) the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I.

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. If 1,000 F2 offspring resulted from the cross, approximately how many of them would you expect to have red, terminal flowers? (Assume independent assortment.) A) 65 B) 190 C) 250 D) 565 E) 750

B) 190

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

Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. How many genes must be responsible for these coat colors in Labrador retrievers? A) 1 B) 2 C) 3 D) 4

B) 2

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

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

B) Multiple alleles

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.

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 characters is controlled by a single gene. B) The genes controlling the characters obey the law of independent assortment. C) Each of the genes controlling the characters has two alleles. D) Only A and C are correct. E) A, B, and C are correct.

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

Two traits 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 multiple genes. B) The genes controlling the traits obey the law of independent assortment. C) Each of the genes controlling the traits has three alleles. D) Four genes are involved. E) Sixteen different phenotypes are possible.

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

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 "blending." 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 "blending."

A 9:3:3:1 phenotypic ratio is characteristic of which of the following? A) a monohybrid cross B) a dihybrid cross C) a trihybrid cross D) linked genes E) both A and D

B) a dihybrid cross

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 testcross

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether cacti 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) epistasis.

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, suggesting that the traits did not truly disappear in the F1. 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) all of the above

B) parental traits that were not observed in the F1 reappeared in the F2, suggesting that the traits did not truly disappear in the F1

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.

A tall plant is crossed with a short plant, and the progeny are all intermediate in size between the two parental plantsIf 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..

B) polygenic inheritance

P = purple, pp = white. The offspring of a cross between two heterozygous purple-flowering plants (Pp × Pp) results in A) all purple-flowered plants. 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) purple-flowered plants and white-flowered plants

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

When pairs of homologous chromosomes separate during anaphase I, A) the maternal chromosomes all move to the same daughter cell. B) the sister chromatids remain attached to one another. C) recombination is not yet complete. D) the synaptonemal complex is visible under the light microscope.

B) the sister chromatids remain attached to one another.

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) 1/2 B) 1/4 C) 0 D) 1 E) 1/6

C) 0

Huntington's 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.

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

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

C) 3/4

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? 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

Skin color in a 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 a homozygous recessive with a heterozygote, what is the chance of getting an offspring with the homozygous recessive phenotype? 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%

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 and a monohybrid only one. 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 and a monohybrid only one.

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 monohybrid cross involves organisms that are heterozygous for a single character, whereas a dihybrid cross involves organisms that are heterozygous for two characters. D) A monohybrid cross is performed only once, whereas a dihybrid cross is performed twice. E) A monohybrid cross results in a 9:3:3:1 ratio whereas a dihybrid cross gives a 3:1 ratio.

C) A monohybrid cross involves organisms that are heterozygous for a single character, whereas a dihybrid cross involves organisms that are heterozygous for two characters

Mendel's 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

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) CVS B) Ultrasound imaging C) Amniocentesis D) Fetoscopy E) X-ray

C) Amniocentesis

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. 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

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

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 (cc) 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 (cc) prevents any fur color from developing.

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

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.

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.

Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. In one type cross of black x 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.

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.

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) true-breeding.

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

C) ww

Feather color in budgies is determined by two different genes Y and B, one for pigment on the outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. 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

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) 1/2

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 x 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

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

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

D) 2 and 3

A tall plant is crossed with a short plant, and the progeny are all intermediate in size between the two parental plants. This could be an example of A) incomplete dominance. B) polygenic inheritance. C) complete dominance. D) A and B E) B and C

D) A and B

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) All of the F1 progeny resembled one of the parental (P) plants, but only some of the F2 progeny did

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.

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) Anaphase I of meiosis

Feather color in budgies is determined by two different genes Y and B, one for pigment on the outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. 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

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible genotype for the mother? A) IAIA B) IBIB C) ii D) IAi E) IAIB

D) IAi

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is the probable genotype for the mother? A) IAIARR B) IAIARr C) IAirr D) IAiRr E) IAiRR

D) IAiRr

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M and N. Which of the following is a possible partial genotype for the son? A) IBIB B) IBIA C) ii D) IBi E) IAIA

D) IBi

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

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 part of the radish we eat may be oval or long, with long being the dominant characteristic. If true-breeding red long radishes are crossed with true breeding white oval radishes, the F1 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

Natural selection and recombination due to crossing over during meiosis I are related in which of the following ways? A) Recombinants are usually selected against. B) Non-recombinant organisms are usually favored by natural selection if there is environmental change. C) Most recombinants reproduce less frequently than do non-recombinants. D) Recombinants may have combinations of traits that are favored by natural selection. E) Recombination does not affect natural selection.

D) Recombinants may have combinations of traits that are favored by natural selection.

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 F1 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

Tallness (T) 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 F1 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

The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment means that 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.

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.

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.

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

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

In a cross AaBbCc x 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 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 snapdragons, heterozygotes 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%

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 part of the radish we eat may be oval or long, with long being the dominant characteristic. 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

Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether cacti have spines. Homozygous recessive nn cactuses have no spines at all. 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

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) A, B, and C are correct

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

Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. These results indicate which of the following? A) Brown is dominant to black. B) Black is dominant to brown and to yellow. C) Yellow is dominant to black. D)There is incomplete dominance. E) Epistasis is involved.

E) Epistasis is involved.

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

Which 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) It is a method that can be used to determine the number of chromosomes in a plant

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.

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