Exam Name___________________________________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Mendelʹs observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division? A) anaphase I of meiosis B) prophase I of meiosis C) metaphase II of meiosis D) anaphase II of meiosis 1) 2) Albinism is a recessive trait. A man and woman who both have normal pigmentation have one child out of three who has albinism (without melanin pigmentation). What are the genotypes of this childʹs parents? A) One parent must be heterozygous; the other parent can be homozygous dominant, homozygous recessive, or heterozygous. B) One parent must be homozygous dominant; the other parent must be heterozygous. C) One parent must be homozygous for the recessive allele; the other parent can be homozygous dominant, homozygous recessive, or heterozygous. D) Both parents must be heterozygous. 2) 3) Use the following figure to answer the question. The pedigree in the figure shows the transmission of a trait in a particular family. Based on this pattern of transmission, the trait is most likely ________. A) mitochondrial B) autosomal dominant C) sex-linked dominant D) sex-linked recessive 3) 4) Meiosis II is similar to mitosis in that A) the daughter cells are diploid. B) sister chromatids separate during anaphase. C) DNA replicates before the division. D) homologous chromosomes synapse. 4)
5) Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize the amino acid phenylalanine. This amino acid is not naturally produced by humans. Which of the following treatments would be most effective for people with PKU? A) Regulate the diet of the affected persons to severely limit the uptake of phenylalanine. B) Feed the patients the missing enzymes in a regular cycle, such as twice per week. C) Feed the patients an excess of the missing product. D) Feed them the substrate that can be metabolized into phenylalanine. 5) 6) Sex determination in mammals is due to the SRY gene found on the Y chromosome. Which of the following situations could allow a person with an XX karyotype to develop a male phenotype? A) the presence of an extra autosomal chromosome B) translocation of SRY to an X chromosome C) the presence of one normal and one shortened (deleted) X D) the loss of the SRY gene from an autosome 6) 7) The SRY gene is best described as ________. A) an autosomal gene that is required for the expression of genes on the X chromosome B) a gene present on the X chromosome that triggers female development C) an autosomal gene that is required for the expression of genes on the Y chromosome D) a gene present on the Y chromosome that triggers male development 7) 8) What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants? A) Recessive genes occur more frequently in the F1 generation than do dominant ones. B) Genes are composed of DNA. C) There is considerable genetic variation in garden peas. D) Traits are inherited in discrete units and are not the result of ʺblending.ʺ 8) 9) Mendelʹs law of independent assortment has its basis in which of the following events of meiosis I? A) synapsis of homologous chromosomes B) the division of cells at telophase C) alignment of pairs of homologous chromosomes along the middle of the cell D) crossing over of homologous pairs of chromosomes 9) 10) The following question refers to the pedigree chart in the figure for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. What is the likelihood that the offspring of IV-3 and IV-4 will have the trait? A) 0% B) 75% C) 50% D) 100% 10)
11) Use the figure and the following description to answer the question. In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding, dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in the figure, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Which of the boxes marked 1-4 correspond to plants with dark leaves?
A) 2 and 3 B) 4 only C) 1, 2, and 3 D) 1 only
11) 12) During which of the following processes do homologous pairs of chromosomes align adjacent to one another at the metaphase plate of a cell? A) metaphase of mitosis B) telophase II of meiosis C) metaphase I of meiosis D) metaphase II of meiosis 12) 13) If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants? A) Force the plant to self-pollinate to obtain an identical one. B) Clone the plant. C) Backtrack through her previous experiments to obtain another plant with the same traits. D) Breed this plant with another plant with much weaker traits. 13) 14) Which of the following statements would explain a testcross involving F1 dihybrid flies in which more parental-type offspring than recombinant-type offspring are produced? A) Recombination did not occur in the cell during meiosis. B) The two genes are closely linked on the same chromosome. C) Both of the characters are controlled by more than one gene. D) The two genes are linked but on different chromosomes. 14) 15) Mitochondrial DNA is primarily involved in coding for proteins needed for protein complexes of the electron transport chain and ATP synthase. Therefore, mutations in mitochondrial genes would most affect which of the following processes? A) the storage of urine in the urinary bladder B) DNA synthesis in cells of the immune system C) generation of ATP in muscle cells D) the movement of oxygen into erythrocytes 15)
16) Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their 20s. How likely is it for a woman to have this condition? A) Women can never have this condition. B) One-half of the daughters of an affected father and a carrier mother could have this condition. C) Only if a woman is XXX could she have this condition. D) One-fourth of the daughters of an affected man would have this condition. 16) 17) A couple has a child with Down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the childʹs condition? A) The mother had a chromosomal duplication. B) One member of the couple underwent nondisjunction in somatic cell production. C) One of the gametes in the mother most likely underwent nondisjunction during meiosis. D) The woman inherited this tendency from her parents. 17) 18) How does natural selection apply to sexual reproduction as opposed to asexual reproduction? A) Sexual reproduction utilizes far less energy than asexual reproduction. B) Sexual reproduction allows the greatest number of offspring to be produced. C) Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction. D) Sexual reproduction results in the greatest number of new mutations. 18) 19) Use the figure and the following description to answer the question. In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding, dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in the figure, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square. Which of the boxes marked 1-4 correspond to plants with a heterozygous genotype?
A) 1, 2, and 3 B) 1 C) 2 and 3 D) 2, 3, and 4
19) 20) 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 crosses BbTt × BBtt will be expected to have black fur and long tails? A) 3/8 B) 1/16 C) 9/16 D) 1/2 20)
21) Inheritance patterns cannot always be explained by Mendelʹs models of inheritance. If a pair of homologous chromosomes fails to separate during meiosis I, select the choice that shows the chromosome number of the four resulting gametes with respect to the normal haploid number (n)? A) n + 1; n - 1; n; n B) n + 1; n - 1; n - 1; n - 1 C) n + 1; n + 1; n - 1; n - 1 D) n + 1; n + 1; n; n 21) 22) Use the following map of four genes on a chromosome to answer the question. Between which two genes would you expect the highest frequency of recombination?
A) E and G B) A and W C) A and E D) A and G
22) 23) In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common? A) length, centromere position, staining pattern, and traits coded for by their genes B) length, centromere position, and staining pattern only C) length and position of the centromere only D) They have nothing in common except that they are X-shaped. 23) 24) The following question refers to the pedigree chart in the figure for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. What is the genotype of individual II-5? A) Ww B) ww C) WW D) ww or Ww 24) 25) Which of the following statements is true of a species that has a chromosome number of 2 n = 16? A) The species has 16 sets of chromosomes per cell. B) Each diploid cell has eight homologous pairs of chromosomes. C) The species is diploid with 32 chromosomes per cell. D) A gamete from this species has four chromosomes. 25)
26) 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 doesnʹt 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) AB and O B) A and B C) A, B, and O D) A, B, AB, and O 26) 27) The figure shows the pedigree for a family. Dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individualʹs age at the time of diagnosis. Males are represented by squares, females by circles. From this pedigree, this trait seems to be inherited ________. A) as a result of epistasis B) as an autosomal dominant C) as an autosomal recessive D) from mothers 27) 28) Asexual reproduction occurs during which of the following processes? A) fertilization B) the exchange of chromosomes between organisms of different species C) meiosis D) mitosis 28) 29) Quaking aspen trees can send out underground stems for asexual reproduction. Sexual reproduction is not as common, but when it does happen, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems? A) 10 B) 38 C) 9 D) 19 29) 30) Which of the following statements correctly describes a karyotype? A) It reveals the appearance of an organism. B) It is a display of all of the cell types in an organism. C) It is a display of a cellʹs mitotic stages. D) It is an organized image of a cellʹs chromosomes. 30)
31) A homozygous tomato plant with red fruit and yellow flowers was crossed with a homozygous tomato plant with golden fruit and white flowers. The F1 all had red fruit and yellow flowers. The F1 were testcrossed by crossing them to homozygous recessive individuals, and the following offspring were obtained: Red fruit and yellow flowers41 Red fruit and white flowers7 Golden fruit and yellow flowers8 Golden fruit and white flowers44 How many map units separate these genes? A) 17.6 B) 17.1 C) 15 D) 18.1 31) 32) Which of the following statements defines a genome? A) the complete set of a speciesʹ polypeptides B) a karyotype C) the complete set of an organismʹs genes and other DNA sequences D) the complete set of an organismʹs polypeptides 32) 33) Which of the following statements is correct in describing the terms monohybrid cross and dihybrid cross? A) 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. B) A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents. C) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. D) A monohybrid cross results in a 9:3:3:1 ratio, whereas a dihybrid cross gives a 3:1 ratio. 33) 34) A man who is a dwarf with achondroplasia and normal vision marries a color-blind woman of normal height. The manʹs father was six feet tall, and both the womanʹs parents were of average height. Dwarfism caused by achondroplasia is autosomal dominant, and red-green color blindness is X-linked recessive. How many of their daughters might be expected to be color-blind with achondroplasia? A) half B) three out of four C) none D) one out of four 34) 35) Which of the following processes might produce a human zygote with 45 chromosomes? A) failure of the egg nucleus to be fertilized by the sperm B) an error in meiotic anaphase occurring in either an egg or sperm C) incomplete cytokinesis during spermatogenesis after meiosis I D) failure of an egg to complete meiosis II 35) 36) A particular organism has 46 chromosomes in its karyotype. Which of the following statements is correct regarding this organism? A) It reproduces sexually. B) It produces gametes with 23 chromosomes. C) It must be an animal. D) It must be human. 36)
37) Which of the following scenarios describes an example of epistasis? A) In rabbits and many other mammals, one genotype ( ee) prevents any fur color from developing. B) In cacti, there are several genes for the type of spines. C) Recessive genotypes for each of two genes (aabb) results in an albino corn snake. D) In Drosophila (fruit flies), white eyes can be due to an X-linked gene or to a combination of other genes. 37) 38) Why did all of the F1 offspring of Mendelʹs classic pea cross always look like one of the two parental varieties? A) One allele was dominant. B) Each allele affected phenotypic expression. C) No genes interacted to produce the parental phenotype. D) The traits blended together during fertilization. 38) 39) One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this type of chromosomal alteration called?
A) duplication B) translocation C) inversion D) deletion
39) 40) Why are males more often affected by sex-linked traits than females? A) X chromosomes in males generally have more mutations than X chromosomes in females. B) Males are hemizygous for the X chromosome. C) Male hormones such as testosterone often alter the effects of mutations on the X chromosome. D) Female hormones such as estrogen often compensate for the effects of mutations on the X chromosome. 40)
41) When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 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 located on the X chromosome. B) The gene involved is located on an autosome, but only in males. C) The gene involved is located on the Y chromosome. D) Other male-specific factors influence eye color in flies. 41) 42) Which of the following statements regarding gene linkage is correct? A) All of the traits that Mendel studiedseed color, pod shape, flower color, and othersare due to genes linked on the same chromosome. B) The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them. C) Linked genes are found on different chromosomes. D) The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%. 42) 43) During which of the following processes do sister chromatids separate from each other? A) during both mitosis and meiosis II B) during meiosis II only C) during both mitosis and meiosis I D) during meiosis I only 43)
44) Which of the following statements correctly describes the meaning of the chromosome theory of inheritance as expressed in the early 20th century? A) Mendelian genes are at specific loci on the chromosome and, in turn, segregate during meiosis. B) Natural selection acts on certain chromosome combinations rather than on genes. C) No more than a single pair of chromosomes can be found in a healthy normal cell. D) Individuals inherit particular chromosomes attached to genes. 44) 45) What is the probability of producing the genotype AABBCC in a cross of individuals who both possess this genotype: AaBbCc? A) 1/16 B) 1/64 C) 1/8 D) 1/4 45)
