Unit 5 MCQ Flashcards
Which of the following statements correctly describes the chromosomes in each daughter cell at the end of meiosis I?
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.
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?
Mitosis produces two identical diploid daughter cells after one round of division. Meiosis produces four haploid daughter cells after two rounds of division.
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?
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.
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?
Is the level of genetic variation in the gametes related to the amount of DNA methylation observed?
During prophase I replicated homologous chromosomes pair up and undergo synapsis. What testable question is generated regarding synapsis and genetic variability by Figure 1 ?
Is the distance between two gene loci related to crossover rate?
Which of the following questions about genetic diversity could most appropriately be answered by analysis of the model in Figure 1 ?
How does the independent assortment of the two sets of homologous chromosomes increase genetic diversity?
How would the extra chromosome affect the male offspring produced by the gamete?
The male offspring would have full-color vision, because of the presence of the extra X chromosome.
If the normal spermatogenesis is disrupted, the gametes can have different chromosomes than expected. Which of the following is the most likely cause of one of the four gametes having two X chromosomes and one having neither an X nor a Y chromosome?
Nondisjunction of the X chromosome during meiosis II
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?
At older maternal ages, the incidence of errors in meiosis during egg production increases, which leads to an increase in nondisjunction.
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?
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 best explains the cause of the phenotypic variation observed in the butterflies?
There was differential gene expression of wing color and body size in response to the colors of light the caterpillars were exposed to.
The researchers calculate a chi-square value of 4.6 and choose a significance level of p=0.05. Which of the following statements best completes the chi-square goodness-of-fit test?
The null hypothesis cannot be rejected because the chi-square value is less than the critical value.
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?
Incubation temperatures above 32°C inhibit the genes on the Z chromosome that produce proteins necessary for male development.
Which of the following best explains how the sweet pea plants in the parental generation produce F1 offspring with 14 chromosomes?
Meiosis I and II lead to the formation of cells with 7 chromosomes. During meiosis I , homologous chromosomes separate. During meiosis II , sister chromatids separate. Two cells combine during fertilization to produce offspring with 14 chromosomes.
Which of the following questions would be most useful to researchers trying to determine the role of meiosis in the F2 phenotypic frequencies?
What is the recombination frequency between the genes for petal shape and pollen shape?
How many degrees of freedom should be used when looking up the critical value for a chi-square analysis of the ratios of phenotypes observed among the F2 offspring versus the expected phenotypic ratio assuming independent assortment?
3
For sexually reproducing diploid parent cells, which of the following statements best explains the production of haploid cells that occurs in meiosis but not in mitosis?
Separation of chromatids occurs once, and there are two rounds of cell division in meiosis.
Which of the following best explains a distinction between metaphase I and metaphase II?
Homologous pairs of chromosomes are aligned during metaphase I , but individual chromosomes are aligned during metaphase II .
A compound that prevents the separation of the homologous chromosomes in anaphase I is being studied. Which of the following questions can be best answered during this study?
Is there a pattern to the movement of homologous chromosomes in the presence of this compound?
Based on Figure 1, which of the following questions could best be addressed?
Does synapsis of homologous chromosomes in the parent cell contribute to an increase in genetic diversity in the daughter cells?
Which of the following is closest to the calculated chi-square (χ2) value for the data presented in Table 1?
72.01
Based on the data in Figure 1, which of the following is the best prediction of the mode of inheritance of red eyes in Japanese koi?
The allele for red eyes is inherited in an autosomal dominant pattern.
Using a significance level of p=0.05, which of the following statements best completes a chi-square goodness-of-fit test for a model of independent assortment
The calculated chi-square value is 3.91, and the critical value is 7.82. The null hypothesis cannot be rejected.
For this condition, which of the following modes of inheritance is most consistent with the observations?
Autosomal dominant
