Bio Chap 13, 14, 15 AP Classroom Questions

Butterflies of the genus Colias live in the Rocky Mountains, where they experience a wide range of temperatures. Different variants of a particular glycolytic enzyme in the flight muscles are optimally active at different temperatures. Within the same population, some individual butterflies fly most effectively at 29°C , while others fly most effectively at 40°C. Still others can be equally active at both temperatures. Which of the following claims is most consistent with the observed butterfly behavior? A Butterflies that express two variants of the enzyme are active over a greater range of temperature. B Butterflies that are active over a wide range of temperatures produce greater amounts of the enzyme. C Temperature has little effect on the activity of butterflies. D Butterflies that are active at warmer temperatures produce more offspring.

A) Butterflies that express two variants of the enzyme are active over a greater range of temperature.

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

A) Crossing-over

In the spring and summer, the fur of an arctic fox contains a pigment called melanin that gives the fox's fur a dark color. In the fall and winter, the fur of the arctic fox is white. Which of the following most likely explains how the changing seasons result in changing fur color in an arctic fox? A Environmental factors cause changes in gene expression, resulting in seasonal variations in pigment production. B Environmental factors cause different mutations in DNADNA during different seasons, resulting in seasonal changes in fur phenotype. C Environmental factors cause proteins to be translated using different genetic codes during different seasons, resulting in variations in pigment production. D Environmental factors cause enzymes to react with different substrates, resulting in the accumulation of different pigments.

A) Environmental factors cause changes in gene expression, resulting in seasonal variations in pigment production.

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? A It is dominant. B It is recessive. C It is codominant. D It is a polygenic inheritance pattern. E The alleles are linked.

A) It is dominant

Which of the following occurs in all species of living organisms and may lead to an increase in genetic variation? A Mutations in the genome B Crossing-over in meiosis C Random assortment of chromosomes D Alternative splicing of mRNA

A) Mutations in the genome

A researcher observes that when two heterozygous plants with red flowers are crossed, the resulting offspring include plants with red, white, or pink flowers. The researcher proposes the null hypothesis that flower color is the result of independent assortment and incomplete dominance. The researcher calculates a chi-square value of 7.37.3. Assuming two degrees of freedom, which of the following is the correct interpretation of the chi-square analysis, using a p-value of 0.05? A The null hypothesis should be rejected because the critical value is less than the calculated value. B The null hypothesis should not be rejected because the critical value is less than the calculated value. C The null hypothesis should not be rejected because the critical value is greater than the calculated value. D The null hypothesis should be rejected because the critical value is greater than the calculated value.

A) The null hypothesis should be rejected because the critical value is less than the calculated value.

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 A 0 B 1/16 C 1/4 D 1/2 E 3/4

B) 1/16

In sheep, eye color is controlled by a single gene with two alleles. When a homozygous brown-eyed sheep is crossed with a homozygous green-eyed sheep, blue-eyed offspring are produced. If the blue-eyed sheep are mated with each other, what percent of their offspring will most likely have brown eyes? A 0% B 25% C 50% D 75% E 100%

B) 25%

The diploid number of chromosomes in the cell of a domesticated dog is 7878. Which of the following options includes the correct number of chromosomes in a cell after each cellular process (G2G2 checkpoint, meiosis, and fertilization, respectively)? A After G2G2CheckpointAfterMeiosisAfterFertilization15615678783939 B After G2G2CheckpointAfterMeiosisAfterFertilization787839397878 C After G2G2CheckpointAfterMeiosisAfterFertilization15615639397878 D After G2G2CheckpointAfterMeiosisAfterFertilization787878783939

B) After G2G2CheckpointAfterMeiosisAfterFertilization787839397878

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? A Blue flowers are incompletely dominant to pink flowers. B Pink flower color is a trait recessive to blue flower color. C Pink flower color is the result of somatic mutations in the flower color gene. D A previous generation of the blue-flowered parent must have included 50 percent pinkflowered plants.

B) Pink flower color is a trait recessive to blue flower color.

In pea plants, flower color and the length of the flower's pollen grains are genetically determined. Researchers studying pea plants crossed homozygous dominant pea plants with homozygous recessive pea plants. The F1�1 plants were then crossed, and the number of offspring with each phenotype was recorded. The researchers' observed data, however, differed from the expected data. The researchers did a chi-square analysis and calculated the chi-square value to be 5.55.5. Based on their calculation, the researchers would most likely conclude which of the following? A The genes that determine these two traits are likely on the same chromosome. B The differences between observed data and expected data are due to chance. C The genes mutated since the researchers began the experiment and now have a different inheritance pattern. D The allele frequencies of the offspring have changed, suggesting the population is evolving.

B) The differences between observed data and expected data are due to chance.

Figure 1. Pedigree of an inherited trait Based on the pedigree in Figure 1, which of the following best explains the observed pattern of inheritance? A The trait is autosomal dominant, because the cross between individuals I-3I-3 and I-4I-4 produced an affected offspring. B The trait is autosomal recessive, because the cross between individuals I-1I-1 and I-2I-2 produced an affected offspring. C The trait is sex-linked dominant, because the cross between individuals II-5II-5 and II-6II-6 produced an affected male. D The trait is sex-linked recessive, because the cross between individuals II-2II-2 and II-3II-3 produced an affected female.

B) The trait is autosomal recessive, because the cross between individuals I-1I-1 and I-2I-2 produced an affected offspring.

A genetic counselor is consulted by a young man who is worried about developing Huntington's disease, an inherited disorder caused by a dominant allele of a single gene. The young man explains that his cousin was recently diagnosed with Huntington's disease, and the news has caused him to consider his own risk of developing the disorder. Which of the following questions will best help the genetic counselor to evaluate the risk of the young man developing Huntington's disease and transmitting it to his children? A Were you and your cousin born in the same geographical area? B Were your parents or grandparents ever diagnosed with Huntington's disease? C Were you in physical contact with a person diagnosed with Huntington's disease? D Were you ever exposed to substances that are suspected of being mutagens?

B) Were your parents or grandparents ever diagnosed with Huntington's disease?

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 A 0 B 1/16 C 1/4 D 1/2 E 3/4

C) 1/4

If 2n = 48 for a particular cell, then the chromosome number in each cell after meiosis would be A 96 B 48 C 24 D 12 E 6

C) 24

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 A 0% B 25% C 50% D 75% E 100%

C) 50%

A scientist is investigating the possibility that two traits in a particular plant are determined by genes that are on the same chromosome. The scientist crossed a plant that is homozygous dominant for both traits with a plant that is homozygous recessive for both traits. The heterozygous offspring in the F1F1 generation were then crossed with a plant that is homozygous recessive for both traits. The results expected if the genes independently assort and the observed results are presented in the table. PhenotypeExpected Number in F2�2Observed Number in F2�2Long stems, white flowers25251717Short stems, red flowers25251919Long stems, red flowers25253131Short stems, white flowers25253333Total number of plants100100100100 Which of the following critical values should the scientist use for the chi-square analysis of the data? A 3.00 B 3.84 C 7.81 D 8.00

C) 7.81

In most vertebrates, the sperm cell normally contributes which of the following to the new organism? A Many mitochondria B Significant amounts of RNA C A haploid complement of chromosomes D Most of the cytoplasm of the zygote E Two sex chromosomes

C) A haploid complement of chromosomes

An African violet grower observes that genetically identical African violet plants growing near the walls of the greenhouse have white flowers, that plants growing farther away from the walls have pale blue flowers, and that plants growing nearest the center of the greenhouse have dark blue flowers. Which of the following best explains the differences in flower color of the African violets in the greenhouse? A Warmer temperatures result in genotypic alterations, which result in flower color differences. B The plants along the walls of the greenhouse are homozygous recessive and therefore have white flowers. C An enzyme responsible for flower color does not fold correctly in cooler temperatures, and the greenhouse is warmest in the center. D More light is available along the walls of the greenhouse, so the flowers need less pigment to absorb sunlight for photosynthesis.

C) An enzyme responsible for flower color does not fold correctly in cooler temperatures, and the greenhouse is warmest in the center.

Trisomy 21 is a condition in which a child is born with an extra chromosome in pair 21. Researchers assessed the frequency of children born with trisomy 21 by age of the mothers at birth (maternal age) and primary cause of the error leading to trisomy 21. The findings are presented in Figure 1. Figure 1. Incidence and primary cause of trisomy 21 by maternal age-group Based on the data in Figure 1, which of the following is most likely the primary cause of the pattern of frequency of trisomy 21 births in the selected maternal age-groups? A At older maternal ages, there is an increase in the number of errors during mitosis, which leads to an increase in nondisjunction during egg production. B The incidence of nondisjunction errors in meiosis during sperm production is positively correlated with increasing maternal age. C At older maternal ages, the incidence of errors in meiosis during egg production increases, which leads to an increase in nondisjunction. D Errors in meiosis leading to nondisjunction are more likely to occur during meiosis II than during meiosis IIII.

C) At older maternal ages, the incidence of errors in meiosis during egg production increases, which leads to an increase in nondisjunction.

A model showing two possible arrangements of chromosomes during meiosis is shown in Figure 1. Figure 1. Two possible arrangements of chromosomes during meiosis Which of the following questions about genetic diversity could most appropriately be answered by analysis of the model in Figure 1 ? A Does crossing-over generate more genetic diversity than the fusion of gametes does? B Does DNADNA methylation prevent independent assortment during metaphase IIII? C How does the independent assortment of the two sets of homologous chromosomes increase genetic diversity? D Do daughter cells that are not genetically identical to parent cells produce viable zygotes?

C) How does the independent assortment of the two sets of homologous chromosomes increase genetic diversity?

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? A I, II, III, IV B II, I, III, IV C III, I, II, IV D III, IV, II, I E IV, II, III, I

C) III, I, II, IV

Figure 1. A cellular process Which of the following best describes the cellular process illustrated in Figure 1 ? A Sister chromatids separating during anaphase of mitosis B Chromosomes lining up along the midline of the cell during mitosis C Reducing the chromosome number during anaphase II of meiosis D Chromatids failing to separate during meiosis

C) Reducing the chromosome number during anaphase II of meiosis

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

C) The diagram illustrates the results of nondisjunction during gamete formation.

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. Potential Offspring With No Error in MeiosisPotential Offspring With Error in MeiosisXBX�YYXBYX�YXbX�XBXbX�X�XbYX�YXB=Full color visionXb=Red-green colorblindX�=Full color visionX�=Red-green colorblindXbX�XbX�XbXBYX�X�YXbX�XBXbX�X�XbYX�YXbX�XbX�XbXBYX�X�Y 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? A None 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 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 A 0 B 1/16 C 1/4 D 1/2 E 3/4

D) 1/2

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 A 0 B 1/16 C 1/4 D 1/2 E 3/4

D) 1/2

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. If three children are born to Matthew and Jane, what are the chances that the first two children will not express the trait but that the third child will be an achondroplastic dwarf? A 5/8 B 4/8 C 3/8 D 1/8 E 1/16

D) 1/8

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 MatthewJaneAAAa B MatthewJaneAaaa C MatthewJaneaaaa D MatthewJaneaaAa E MatthewJaneAaAa

D) MatthewJaneaaAa

In fruit flies of the genus Drosophila, the allele for vestigial wings is recessive to the allele for round wings, and the allele for brown eye color is recessive to the allele for red eye color. A scientist crossed flies that are heterozygous for both traits and determined the number of offspring with each combination of phenotypes. The scientist performed a chi-square analysis to determine if the data are consistent with the expectations for independent assortment. The chi-square calculated value for the experiment was 6.036.03. Based on the chi-square calculated value, which of the following statements is most accurate? A The chi-square calculated value is greater than the chi-square critical value; therefore the null hypothesis should be rejected. B The chi-square calculated value is greater than the chi-square critical value; therefore the null hypothesis should not be rejected. C The chi-square calculated value is less than the chi-square critical value; therefore the null hypothesis should be rejected. D The chi-square calculated value is less than the chi-square critical value; therefore the null hypothesis should not be rejected.

D) The chi-square calculated value is less than the chi-square critical value; therefore the null hypothesis should not be rejected.

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. Table 1. Effect of Exposing Identical Caterpillars to Specific Colors of Light Phenotype of Adult ButterflyCaterpillars Exposed to Red LightCaterpillars Exposed to Blue LightWing colorDarkerLighterBody sizeSmallerLarger Which of the following best explains the cause of the phenotypic variation observed in the butterflies? A Different mutations occurred in the caterpillars that were exposed to different colors of light. B The energy used to grow a larger body results in butterflies with lighter colored wings. C Individual caterpillars evolved adaptations to survive in each of the light conditions they were exposed to. D There was differential gene expression of wing color and body size in response to the colors of light the caterpillars were exposed to.

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

In peas the trait for tall plants is dominant (T) and the trait for short plants is recessive (t). The trait for yellow seed color is dominant (Y) and the trait for green seed color is recessive (y). A cross between two plants results in 296 tall yellow plants and 104 tall green plants. Which of the following are most likely to be the genotypes of the parents? A TTYY x TTYY B TTyy x TTYy C TtYy x TtYy D TtYy x TTYy E TtYY x Ttyy

D) TtYy x TTYy

Hydrangea flowers differ in color based on interactions between a pigment in the flower cells and aluminum ions dissolved in water absorbed from the soil. When aluminum ions are present, the pigment is blue; when aluminum ions are absent, the pigment is pink. The amount of aluminum ions the plant can absorb is dependent on the pHpH of the soil. Which of the following questions will best help a researcher design an experiment to learn about the relationship between hydrangea flower color, aluminum, and pHpH? A How do aluminum-pigment interactions change the structure of the pigment and flower color? B Can the pigment be used as an indicator of pHpH, because flower color depends on pHpH and aluminum? C Does an increase in hydrogen ion concentration affect the ability of the pigment to dissolve in water? D What will be the flower color of hydrangeas grown in soils of varying pHpH with or without aluminum?

D) What will be the flower color of hydrangeas grown in soils of varying pH with or without aluminum?