Unit 5 progress check

A student crosses a pure-breeding line of red-flowered poinsettias with a pure-breeding line of white-flowered poinsettias. The student observes that all the plants in the F1F1 generation have pink flowers. The student then crosses the F1F1 plants with one another and records observations about the plants in the F2F2 generation. The student will use the F2F2 data to perform a chi-square goodness-of-fit test for a model of incomplete dominance. The setup for the student's chi-square goodness-of-fit test is presented in Table 1. The critical value for a chi-square test with a significance level of p=0.05p=0.05 and 2 degrees of freedom is 5.99. Which of the following statements best completes the student's chi-square goodness-of-fit test? A The calculated chi-square value is 1.53, and the null hypothesis cannot be rejected. B The calculated chi-square value is 1.53, and the null hypothesis can be rejected. C The calculated chi-square value is 98, and the null hypothesis cannot be rejected. D The calculated chi-square value is 98, and the null hypothesis can be rejected.

A The calculated chi-square value is 1.53, and the null hypothesis cannot be rejected.

In a strain of tomato plants, short plant height and small fruit size are traits that display autosomal recessive patterns of inheritance. To investigate whether the traits segregate independently, researchers cross a pure-breeding line of tall tomato plants that have large fruits with a pure-breeding line of short tomato plants that have small fruits. The researchers observe that all the plants in the F1F1 generation are tall and have large fruits. The researchers cross the F1F1 plants with one another to generate an F2F2 generation. The researchers record observations for the F2F2 generation and will use the data to perform a chi-square goodness-of-fit test for a model of independent assortment. The setup for the chi-square goodness-of-fit test is shown in Table 1. The researchers choose a significance level of p=0.05p=0.05. Which of the following best completes the chi-square goodness-of-fit test? A The calculated chi-square value is 9.24, and the critical value is 7.82. The null hypothesis of independent assortment can be rejected. B The calculated chi-square value is 9.24, and the critical value is 9.49. The null hypothesis of independent assortment cannot be rejected. C The calculated chi-square value is 13.13, and the critical value is 7.82. The null hypothesis of independent assortment can be rejected. D The calculated chi-square value is 13.13, and the critical value is 9.49. The null hypothesis of independent assortment cannot be rejected.

A The calculated chi-square value is 9.24, and the critical value is 7.82. The null hypothesis of independent assortment can be rejected.

The diagram above illustrates which of the following processes? ACrossing-over B Base pair substitution C Duplication D Deletion E Posttranscriptional processing

ACrossing-over

Figure 1. Model of crossing over between homologous chromosomes, indicating crossing over rate of selected loci. During prophase II replicated homologous chromosomes pair up and undergo synapsis. What testable question is generated regarding synapsis and genetic variability by Figure 1 ? AIs the distance between two gene loci related to crossover rate? BDoes crossing over occur more often in some chromosomes than in others? CIs crossing over inhibited by methylation? DIs crossing over promoted by methylation?

AIs the distance between two gene loci related to crossover rate?

Directions: Each group of questions below concerns an experimental or a laboratory situation. In each case, first study the description of the situation. Then choose the one best answer to each question following it. In dogs, one pair of alleles determines coat color (dark and albino). Another pair of alleles determines hair length (short and long). Thus, each gamete will contain one of the coat-color alleles, C or c and one of the hair-length alleles, B or b. In repeated crosses of a specific dark, short-haired dog with an albino, long-haired dog, all the offspring were dark with short hair, as shown in cross I. However, in subsequent crosses of another dark, short-haired dog with a dark, long-haired dog, the ratios shown in cross II below were obtained. Which of the following correctly describes the relationship of the dark-coat-color allele to the albino condition? AIt is dominant. BIt is recessive. CIt is codominant. DIt is a polygenic inheritance pattern. EThe alleles are linked.

AIt is dominant.

In garden peas, a single gene controls stem length. The recessive allele (t) produces short stems when homozygous. The dominant allele (T) produces long stems. A short-stemmed plant is crossed with a heterozygous long-stemmed plant. Which of the following represents the expected phenotypes of the offspring and the ratio in which they will occur? A 3 long-stemmed plants: 1 short-stemmed plant B 1 long-stemmed plant: 1 short-stemmed plant C 1 long-stemmed plant: 3 short-stemmed plants D Long-stemmed plants only E Short-stemmed plants only

B 1 long-stemmed plant: 1 short-stemmed plant

A couple has 5 children, all sons. If the woman gives birth to a sixth child, what is the probability that the sixth child will be a son? A 5/6 B 1/2 C 1/5 D 1/6 E 1/64

B 1/2

For following group of questions first study the description of the situation and diagram and then choose the one best answer to each question following it and fill in the corresponding oval on the answer sheet. The pedigree of a family with a history of a particular genetic disease is shown below. Squares represent males and circles represent females. Shaded symbols represent those who have the disease. If Individual 2 were to marry a woman with no family history of the disease, which of the following would most likely be true of their children? A All of the children would have the disease. B None of the children would have the disease. C Only the sons would have the disease. D All of the sons would be carriers of the disease. E None of the daughters would be carriers of the disease.

B None of the children would have the disease.

Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. This group of questions refers to the probabilities below. Assume that the alleles referred to all assort independently.(A) 0(B) 1/16(C) 1/4(D) 1/2(E) 3/4 Probability that the genotype ccdd will be produced by the parents CcDd x CcDd A0 B1/16 C1/4 D1/2 E3/4

B1/16

A blue-flowered African violet of unknown ancestry self-pollinated and produced 50 seeds. These seeds germinate and grow into flowering plants. Of these plants, 36 produce blue flowers and 14 produce pink flowers. What is the best explanation for the pink-flowered offspring? ABlue flowers are incompletely dominant to pink flowers. BPink flower color is a trait recessive to blue flower color. CPink flower color is the result of somatic mutations in the flower color gene. DA previous generation of the blue-flowered parent must have included 50 percent pinkflowered plants.

BPink flower color is a trait recessive to blue flower color.

Within a forest ecosystem, there is a large amount of diversity among members of a warbler species. Of the following stages of meiosis illustrated for a typical cell, which contributes most to diversity among the warblers?

C

Gregor Mendel's pioneering genetic experiments with pea plants occurred before the discovery of the structure and function of chromosomes. Which of the following observations about inheritance in pea plants could be explained only after the discovery that genes may be linked on a chromosome? A Pea color and pea shape display independent inheritance patterns. B Offspring of a given cross show all possible combinations of traits in equal proportions. C Most offspring of a given cross have a combination of traits that is identical to that of either one parent or the other. D Recessive phenotypes can skip a generation, showing up only in the parental and F2 generations.

C Most offspring of a given cross have a combination of traits that is identical to that of either one parent or the other.

The relative location of four genes on a chromosome can be mapped from the following data on crossover frequencies Which of the following represents the relative positions of these four genes on the chromosome? A.ABCD BADCB C.CABD DCBAD EDBCA

C.CABD

Directions: Each group of questions below concerns an experimental or a laboratory situation. In each case, first study the description of the situation. Then choose the one best answer to each question following it. In dogs, one pair of alleles determines coat color (dark and albino). Another pair of alleles determines hair length (short and long). Thus, each gamete will contain one of the coat-color alleles, C or c and one of the hair-length alleles, B or b. In repeated crosses of a specific dark, short-haired dog with an albino, long-haired dog, all the offspring were dark with short hair, as shown in cross I. However, in subsequent crosses of another dark, short-haired dog with a dark, long-haired dog, the ratios shown in cross II below were obtained. In cross II, the genotype of the dark, short-haired parent is ACcBb Bccbb C.CCBB DCCbb EccBB

C.CCBB

Red-green color blindness in humans is caused by a recessive allele located on the XX chromosome. Figure 1 shows the potential offspring of a female who is red-green color-blind and a male with full-color vision. All of the possible male offspring would be color-blind, and all of the possible female offspring would have full-color vision. If during the production of male gametes an error in meiosis occurred, sperm containing both an XX and a YY chromosome could be produced.Figure 1. Possible offspring of a female who is red-green color-blind and a male who has full-color vision. How would the extra chromosome affect the male offspring produced by the gamete? ANone of the potential offspring would be male, because the potentially male zygote would have two XX chromosomes, and the YY chromosome would be ignored. B The male offspring would all be red-green color-blind, because of interference from alleles on the YY chromosome. C The male offspring would have full-color vision, because of the presence of the extra XX chromosome. D There would be no change to the phenotypes of the possible offspring, because the extra XX chromosome would not be active.

C.The male offspring would have full-color vision, because of the presence of the extra XX chromosome.

This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. This group of questions refers to the probabilities below. Assume that the alleles referred to all assort independently.(A) 0(B) 1/16(C) 1/4(D) 1/2(E) 3/4 Probability that the genotype TTSs will be produced by the parents TTSs x TtSS A0 B1/16 C1/4 D1/2 E3/4

C1/4

If 2n = 48 for a particular cell, then the chromosome number in each cell after meiosis would be A96 B48 C24 D12 E6

C24

Directions: Each group of questions below concerns an experimental or laboratory situation or data. In each case, first study the description of the situation or data. Then choose the one best answer to each question following it. Achondroplastic dwarfism is a dominant genetic trait that causes severe malformation of the skeleton. Homozygotes for this condition are spontaneously aborted (hence, the homozygous condition is lethal) but heterozygotes will develop to be dwarfed. Matthew has a family history of the condition, although he does not express the trait. Jane is an achondroplastic dwarf. Matthew and Jane are planning a family of several children and want to know the chances of producing a child with achondroplastic dwarfism. The probability that Matthew and Jane's first child will be an achondroplastic dwarf is A0% B25% C50% D75% E100%

C50%

The events listed below generally take place during meiosis. I. Synapsis occurs.II. Crossing-over is completed.III. Condensation of chromosomes begins.IV. Separation of homologous chromosomes begins. Which of the following is the correct sequence of these events? AI, II, III, IV BII, I, III, IV CIII, I, II, IV DIII, IV, II, I EIV, II, III, I

CIII, I, II, IV

The diagram above depicts a karyotype of an individual human. Which of the following statements concerning the karyotype in the diagram is true? AThe diagram illustrates a genetic condition found in females. BThe diagram indicates a mechanism for increasing genetic diversity in subsequent generations. CThe diagram illustrates the results of nondisjunction during gamete formation. DThe diagram indicates Down syndrome, a genetic condition.

CThe diagram illustrates the results of nondisjunction during gamete formation.

Which of the following best describes the cells that result from the process of meiosis in mammals? AThey are diploid. BThey can be used to repair injuries. CThey are genetically different from the parent cell. DThey are genetically identical to all the other cells in the body. EThey are identical to each other.

CThey are genetically different from the parent cell.

Both mitosis and meiosis begin with a parent cell that is diploid. Which of the following best describes how mitosis and meiosis result in daughter cells with different numbers of chromosomes? A In mitosis, the chromosomes consist of a single chromatid, which is passed to two haploid daughter cells. In meiosis, the chromosomes consist of two chromatids during the first round of division and one chromatid during the second round of division, resulting in two haploid daughter cells. B In mitosis, synapsis of homologous chromosomes results in four haploid daughter cells after one division. In meiosis, synapsis of homologous chromosomes occurs during the second division and results in four diploid daughter cells. C Mitosis produces one identical daughter cell after one round of division. Meiosis has two rounds of division and doubles the number of chromosomes in the second round of division, producing four diploid cells. D Mitosis produces two identical diploid daughter cells after one round of division. Meiosis produces four haploid daughter cells after two rounds of division.

D Mitosis produces two identical diploid daughter cells after one round of division. Meiosis produces four haploid daughter cells after two rounds of division.

In fruit flies, purple eyes and ebony body are traits that display autosomal recessive patterns of inheritance. In a genetics experiment, students cross wild-type flies with flies that have purple eyes and ebony bodies. The students observe that all the flies in the F1F1 generation have normal eyes and a normal body color. The students then allow the F1F1 flies to mate and produce an F2F2 generation. The students record observations about the flies in the F2F2 generation and use the data to perform a chi-square goodness-of-fit test for a model of independent assortment. The setup for the students' chi-square goodness-of-fit test is presented in Table 1. The students choose a significance level of p=0.01p=0.01. Which of the following statements best completes the next step of the chi-square goodness-of-fit test? A The calculated chi-square value is 2.11, and the critical value is 7.82. B The calculated chi-square value is 2.11, and the critical value is 11.35. C The calculated chi-square value is 10.48, and the critical value is 7.82. D The calculated chi-square value is 10.48, and the critical value is 11.35.

D The calculated chi-square value is 10.48, and the critical value is 11.35.

Saccharomyces cerevisiae is a diploid yeast species that can reproduce either sexually or asexually. An experiment was performed to induce mitotically dividing S. cerevisiae cells in G2G2 to undergo meiosis. Which of the following best describes the steps these cells will follow to form gametes? A The first division will result in crossing over between homologous chromosomes, and the second division will reduce the original number of chromosomes by half in the daughter cells. B The first division will reduce the number of chromosomes by half for each daughter cell, and the second division will result in each daughter cell having one-fourth of the original number of chromosomes. C The first division will move single chromatids to each daughter cell, and the second division will double the number of chromosomes in each daughter cell. D The first division will reduce the number of chromosomes by half for each daughter cell, and the second division will move single chromatids to each daughter cell.

D The first division will reduce the number of chromosomes by half for each daughter cell, and the second division will move single chromatids to each daughter cell.

Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. This group of questions refers to the probabilities below. Assume that the alleles referred to all assort independently.(A) 0(B) 1/16(C) 1/4(D) 1/2(E) 3/4 Probability that the genotype Rr will be produced by the parents Rr x rr A0 B1/16 C1/4 D1/2 E3/4

D1/2

This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. This group of questions refers to the probabilities below. Assume that the alleles referred to all assort independently.(A) 0(B) 1/16(C) 1/4(D) 1/2(E) 3/4 Probability that the genotype Aa will be produced by the parents Aa x Aa A0 B1/16 C1/4 D1/2 E3/4

D1/2

In the pedigree above, circles represent females, squares represent males, and shaded figures represent individuals expressing a specific trait. The expression of this trait is most likely due to which of the following? ASex-linked dominant inheritance BSex-linked recessive inheritance CAutosomal dominant inheritance DAutosomal recessive inheritance EA codominant relationship of a single pair of alleles

DAutosomal recessive inheritance

Directions: Each group of questions below concerns an experimental or laboratory situation or data. In each case, first study the description of the situation or data. Then choose the one best answer to each question following it. Achondroplastic dwarfism is a dominant genetic trait that causes severe malformation of the skeleton. Homozygotes for this condition are spontaneously aborted (hence, the homozygous condition is lethal) but heterozygotes will develop to be dwarfed. Matthew has a family history of the condition, although he does not express the trait. Jane is an achondroplastic dwarf. Matthew and Jane are planning a family of several children and want to know the chances of producing a child with achondroplastic dwarfism. The genotypes of Matthew and Jane are best represented as A MatthewJane AA Aa B MatthewJane Aa aa C MatthewJane aa aa DMatthewJane aa Aa EMatthewJane Aa Aa

DMatthewJane aa Aa

A series of crosses is performed with fruit flies (Drosophila melanogaster) to examine inheritance of the genes vestigial (vg) and cinnabar (cn). The recessive vg allele causes small, malformed wings called vestigial wings. The recessive cn allele causes bright-red eyes called cinnabar eyes. In the first cross, a female with wild-type wings and eyes is mated with a male with vestigial wings and cinnabar eyes. All the F1 individuals have wild-type wings and eyes. In the second cross, female F1 flies are mated with males with vestigial wings and cinnabar eyes. The phenotypes of 500 F2 individuals are shown in the table Which of the following is the most likely explanation of the results? AThe two genes are located on two different chromosomes. BThe two genes are sex-linked. CThe two genes are located on mitochondrial DNA. DThe two genes are linked on an autosome.

DThe two genes are linked on an autosome.

A scientist studying phenotypic variation in a species of butterfly observed that genetically identical caterpillars grown in similar cages but exposed to different colored lights developed into butterflies with differences in wing color and body size, as shown in Table 1. Which of the following best explains the cause of the phenotypic variation observed in the butterflies? ADifferent mutations occurred in the caterpillars that were exposed to different colors of light. BThe energy used to grow a larger body results in butterflies with lighter colored wings. CIndividual caterpillars evolved adaptations to survive in each of the light conditions they were exposed to. DThere was differential gene expression of wing color and body size in response to the colors of light the caterpillars were exposed to.

DThere was differential gene expression of wing color and body size in response to the colors of light the caterpillars were exposed to.

In humans, red-green color blindness is a sex-linked recessive trait. If a man and a woman produce a color-blind son, which of the following must be true? A The father is color-blind. B Both parents carry the allele for color blindness. C Neither parent carries the allele for color blindness. D The father carries the allele for color blindness. E The mother carries the allele for color blindness.

E The mother carries the allele for color blindness.

All of the following are true statements about meiosis in mammals EXCEPT: AIt serves as a factor in bringing about variation among offspring. BIt follows DNA replication. CIt occurs only in reproductive structures. DIt produces cells with the haploid number of chromosomes. EIt produces four genetically identical gametes.

EIt produces four genetically identical gametes.