ap bio quiz 5.3 mendelian genetics
A researcher is crossing two organisms that are heterozygous for three Mendelian, unlinked traits (XxYyZzXxYyZz). Which of the following is the fraction of offspring that are predicted to have the genotype xxyyzzxxyyzz? A 1/64 B 1/32 C 1/16 D 1/8
A 1/64
In sweet pea plants, purple flower color is dominant over red flower color and long pollen grain shape is dominant over round pollen grain shape. Two sweet pea plants that are heterozygous for both flower color and pollen grain shape are crossed with one another. A geneticist is surprised to observe that there are far fewer round, purple offspring and long, red offspring than were predicted by the 9:3:3:19:3:3:1 expected phenotypic ratio. Which of the following statements provides the most reasonable prediction to account for the deviation from the expected results? A In sweet pea plants, the gene for flower color and the gene for pollen grain shape are genetically linked. B In sweet pea plants, the genes for flower color and for pollen grain shape both exhibit codominance. C Several mutations occurred spontaneously producing a deviation from the expected phenotypic ratios of the offspring. D The genes for flower color and pollen grain shape are inherited independently because of the law of independent assortment.
A In sweet pea plants, the gene for flower color and the gene for pollen grain shape are genetically linked.
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 critical value for a chi-square test with a significance level of p=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 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.
Insulin is a hormone produced by some pancreatic cells. Scientists have isolated the DNA sequence that codes for human insulin production. Which of the following best predicts the effect of inserting this gene into the DNADNA of a bacterial cell? A The recombinant bacterium will produce human insulin using its own transcription and translation machinery. B The recombinant bacterium will not transcribe the human insulin gene because this gene is not normally found in the bacterial genome. C The recombinant bacterium will transcribe the gene but will be unable to translate the mRNAmRNA. D The recombinant bacterium will die because it has been exposed to foreign DNADNA.
A The recombinant bacterium will produce human insulin using its own transcription and translation machinery.
The Russian blue is a rare breed of cat that is susceptible to developing cataracts on the eyes. Scientists hypothesize that this condition is inherited as a result of a mutation. Figure 1 shows a pedigree obtained in a study of cats owned by members of the Russian Blue Club in Sweden. Figure 1. Pedigree of Russian blue cats owned by Russian Blue Club Based on the inheritance pattern shown in Figure 1, which of the following best predicts the nature of the original mutation? A A recessive mutation on the X chromosome B A recessive mutation on a somatic chromosome C A dominant mutation on the X chromosome D A dominant mutation on a somatic chromosome
B A recessive mutation on a somatic chromosome
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 F1F1 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.
Antibiotics can be used to kill the specific pathogenic bacterium, Mycobacterium tuberculosis, that causes tuberculosis. The appearance of antibiotic-resistant strains has made it more difficult to cure M. tuberculosis infections. These antibiotic-resistant bacteria survive and pass on the genes to their offspring, making the resistant phenotype more common in the population. DNA analysis indicates that the genes for antibiotic resistance are not normally present in bacterial chromosomal DNA. Which of the following statements best explains how the genes for antibiotic resistance can be transmitted between bacteria without the exchange of bacterial chromosomal DNA? A The antibiotic-resistant bacteria release a hormone that signals neighboring bacteria to become resistant. B The genes for antibiotic resistance are located on a plasmid that can be passed to neighboring bacteria. C The antibiotic-resistant bacteria are the result of bacteria that specifically modify their own chromosomal DNA to neutralize the antibiotics. D The antibiotic alters the bacterial genome of each bacterium, which results in an antibiotic-resistant population.
B The genes for antibiotic resistance are located on a plasmid that can be passed to neighboring bacteria.
A researcher hypothesizes that, in mice, two autosomal dominant traits, trait Q and trait R, are determined by separate genes found on the same chromosome. The researcher crosses mice that are heterozygous for both traits and counts the number of offspring with each combination of phenotypes. The total number of offspring produced was 6464. The researcher plans to do a chi-square analysis of the data and calculates the expected number of mice with each combination of phenotypes. Which of the following is the expected number of offspring that will display both trait Q and trait R? A 4 B 12 C 36 D 48
C 36
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. 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.
In pea seeds, yellow color (YY) is dominant to green color (yy), and a round shape (RR) is dominant to a wrinkled shape (rr). A dihybrid cross between a true-breeding plant with yellow, round seeds (YYRR)(YYRR) and a true-breeding plant with green, wrinkled seeds (yyrryyrr) results in an F1F1 generation of plants with yellow, round seeds. Crossing two F1F1 plants produces an F2F2 generation with approximately nine times as many plants with yellow, round seeds as plants with green, wrinkled seeds. Which of the following best explains these results? A The allele pairs of each parent stay together, resulting in gametes that are identical to the parents. B Gene segments on sister chromatids cross over. C Alleles that are on nonhomologous chromosomes recombine. D The genes for seed color and seed shape assort independently.
D The genes for seed color and seed shape assort independently.
