Meiosis and Sexual Reproduction
MULTIPLE CHOICE
1. A human cell containing 22 autosomes and a Y chromosome is:
(a) a somatic cell of a male.
(b) a zygote.
(c) a somatic cell of a female.
(d) a sperm cell.
(e) an ovum.
2. Homologous chromosomes move to opposite poles of a dividing cell during:
(a) mitosis.
(b) meiosis I.
(c) meiosis II.
(d) fertilization.
(e) binary fission.
3. Meiosis II is similar to mitosis in that:
(a) homologous chromosomes synapse.
(b) DNA replicates before the division.
(c) the daughter cells are diploid.
(d) sister chromatids separated during anaphase.
(e) the chromosome number is reduced.
4. The DNA content of a diploid cell in the G1 phase of the cell cycle is measured. If this DNA content is x, then the DNA content of the same cell at metaphase I would be:
(a) 0.25x.
(b) 0.5x.
(c) 1x.
(d) 2x.
(e) 4x.
5. If we continue to follow the cell lineage from question 4, then the DNA content of metaphase of meiosis II would be:
(a) 0.25x.
(b) 0.5x.
(c) 1x.
(d) 2x.
(e) 4x.
6. If we continue to follow the cell lineage from question 4, then the DNA content of one of the cells in telophase of meiosis II would be:
(a) 0.25x.
(b) 0.5x.
(c) 1x.
(d) 2x.
(e) 4x.
7. How many different combinations of maternal and paternal chromosomes can be packaged into gametes made by an organism with a diploid number of 8 (2n = 8)? HINT: Remember independent assortment!
(a) 2
(b) 4
(c) 8
(d) 16
(e) 32
8. Crossing over usually contributes to genetic variation by exchanging chromosomal segments between:
(a) sister chromatids of a chromosome.
(b) chromatids of nonhomologues.
(c) nonsister chromatids of homologues.
(d) nonhomologous loci of the genome.
(e) autosomes and sex chromosomes.
9. A chiasma links a pair of:
(a) homologous chromosomes at meiotic prophase II.
(b) homologous chromosomes at meiotic prophase I.
(c) sister chromatids at meiotic prophase II.
(d) nonsister chromatids at mitotic prophase.
(e) sister chromatids at meiotic prophase I.
10. Meiotic and mitotic cell cycles differ in:
(a) the stage when DNA is synthesized.
(b) the number of chromatids per chromosome in prophase.
(c) whether or not synapsis takes place.
(d) the number of times DNA replicates per cycle.
(e) whether or not chromosomes become oriented on a spindle.
11. Which is not a difference between mitosis and meiosis I?
(a) separation of sister chromatids.
(b) number of chromatids per chromosome in prophase.
(c) formation of chiasmata.
(d) division of centromeres.
(e) formation of tetrads.
12. Genetic variation arises during oogenesis as a direct result of:
(a) chiasmata formation and crossing over during meiosis.
(b) the number of patterns (= ways) in which tetrads can align on the meiotic spindle.
(c) the formation of only one ovum from each oocyte.
(d) a and b, but not c.
(e) a, b, and c.
13. In sexual reproduction:
(a) gametes are usually haploid.
(b) gametes are usually diploid.
(c) the zygote is usually haploid.
(d) the chromosome number is reduced during mitosis.
(e) spores are formed during fertilization.
14. In meiosis:
(a) meiosis II reduces the chromosome number from diploid to haploid.
(b) DNA replicates between meiosis I and II.
(c) the chromatids making up a chromosome in meiosis II are identical.
(d) each chromosome in prophase I consists of four chromatids.
(e) homologous chromosomes are separated from one another in anaphase I.
15. Which of the following aspects of reproduction enhances genetic diversity?
(a) random fertilization.
(b) independent sorting of homologous chromosomes to daughter cells during meiosis.
(c) mitosis.
(d) all of the above (a-c).
(e) a and b, but not c.
TRUE or FALSE
16. If the diploid number of an organism is X (2n = X), then the number of homologous pairs of chromosomes is X/2.
17. Gametes contain one of each kind of chromosome because homologous chromosomes separate during meiosis.
18. Chromosomes that are similar in size, shape, and genetic content, but were received from different parents, are referred to as chromatids.
19. Cells produced by mitosis are diploid; cells produced by meiosis are haploid.
20. In mitosis four daughter cells are produced, whereas in meiosis two daughter cells are produced.
ANSWERS: 1. d
2. b
3. d
4. d
5. c
6. b
7. d
8. c
9. b
10. c
11. b
12. d
13. a
14. e
15. e
16. True
17. True
18. False (Chromosomes that are similar in size, shape, and genetic content, but were received from different parents, are referred to as homologous chromosomes.)
19. True
20. False (In mitosis two daughter cells are produced, whereas in meiosis four daughter cells are produced.)
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