AP BIO UNIT 5

(S)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?

B. A recessive mutation on a somatic chromosome

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?

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

(S) Which of the following best explains the cause of the phenotypic variation observed in the butterflies?

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

(S) 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 9:3:3:1 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.

(S) Figure 1. Model of crossing over between homologous chromosomes, indicating crossing over rate of selected loci. During prophase I replicated homologous chromosomes pair up and undergo synapsis. What testable question is generated regarding synapsis and genetic variability by Figure 1 ?

A. Is the distance between two gene loci related to crossover rate?

Scientists have found that DNA methylation suppresses crossing-over in the fungus Ascobolus immersus. Which of the following questions is most appropriately raised by this specific observation?

A. Is the level of genetic variation in the gametes related to the amount of DNADNA methylation observed?

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 ?

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

(S) 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 DNA of a bacterial cell?

A. The recombinant bacterium will produce human insulin using its own transcription and translation machinery.

(S) 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?

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

Which of the following statements correctly describes the chromosomes in each daughter cell at the end of meiosis I?

C. Each daughter cell contains 12 chromosomes, each composed of two chromatids. Each chromosome is one of a pair of homologous chromosomes from the parent cell, with the other homologue found in the other daughter cell.

(S) Table 1. Offspring from three separate crosses of a brown male pigeon and a red female pigeon. Which of the following is the mean number of male offspring produced by the three crosses?

D. 9

(S) Australian dragon lizards have a ZW sex-determination system. The male genotype is homogametic (ZZ), and the female genotype is heterogametic (ZW). However, all eggs incubated at temperatures above 32°C tend to develop into females. Which of the following best explains how the development of phenotypic female Australian dragon lizards with a ZZ genotype occurs when incubation temperatures are above 32°C?

D. Incubation temperatures above 32°C32°C inhibit the genes on the ZZ chromosome that produce proteins necessary for male development.

(S) 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 G2 to undergo meiosis. Which of the following best describes the steps these cells will follow to form gametes?

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.