Campbell Biology in Focus, 2e (Urry)
Chapter 10 Meiosis and Sexual Life Cycles
10.1 Multiple-Choice Questions
1) If a horticulturist breeding gardenias succeeds in having a single plant with a particularly
desirable set of traits, which of the following would be her most probable and efficient route to
establishing a line of such plants?
A) Backtrack through her previous experiments to obtain another plant with the same traits.
B) Breed this plant with another plant with much weaker traits.
C) Clone the plant asexually to produce an identical one.
D) Force the plant to self-pollinate to obtain an identical one.
2) Which of the following descriptions correctly defines a genome?
A) representation of a complete set of a cell’s polypeptides
B) the complete set of an organism’s polypeptides
C) a karyotype
D) the complete set of an organism’s genes
3) Which of the following is the smallest unit that would contain a complete copy of the entire
human genome?
A) one human somatic cell
B) one human chromosome
C) all of the DNA of one human
D) one human gene
4) If an organism is diploid and a certain gene found in the organism has 18 known alleles
(variants), then any given organism of that species can/must have which of the following?
A) at most, 2 alleles for that gene
B) up to 18 chromosomes with that gene
C) up to 18 genes for that trait
D) up to, but not more than, 18 different traits
5) Which of the following is a true statement about sexual versus asexual reproduction?
A) Asexual reproduction, but not sexual reproduction, is characteristic of plants and fungi.
B) In sexual reproduction, individuals transmit 50% of their genes to each of their offspring.
C) In asexual reproduction, offspring are produced by fertilization without meiosis.
D) Asexual reproduction produces only haploid offspring.
6) At which stage of mitosis are chromosomes usually photographed in the preparation of a
karyotype?
A) prophase
B) metaphase
C) anaphase
D) telophase
7) Which of the following is true of a species that has a chromosome number of 2n = 16?
A) The species has 16 sets of chromosomes per cell.
B) Each cell has eight homologous pairs.
C) During the S phase of the cell cycle there will be 32 separate chromosomes.
D) A gamete from this species has four chromosomes.
8) Eukaryotic sexual life cycles show tremendous variation. Which of the following elements do
all sexual life cycles have in common?
I. alternation of generations
II. meiosis
III. fertilization
IV. gametes
V. spores
A) I, IV, and V
B) I, II, and IV
C) II, III, and IV
D) II, IV, and V
9) Which of these statements is true?
A) In humans, the 23rd pair, the sex chromosomes, determines whether the person is female
(XX) or male (XY).
B) Single, haploid (n) sets of chromosomes in ovum and sperm unite during fertilization,
forming a haploid (n), single-celled zygote.
C) At sexual maturity, ovaries and testes produce diploid gametes by meiosis.
D) Sexual life cycles among different types of organisms are identical with respect to the relative
timing of meiosis and fertilization.
10) Referring to a plant’s sexual life cycle, which of the following processes leads directly to the
formation of gametes?
A) sporophyte meiosis
B) gametophyte mitosis
C) gametophyte meiosis
D) sporophyte mitosis
11) Which of the following is an example of alternation of generations?
A) A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular,
haploid pollen grain (gametophyte).
B) A diploid animal produces gametes by meiosis, and the gametes undergo fertilization to
produce a diploid zygote.
C) A haploid mushroom produces gametes by mitosis, and the gametes undergo fertilization,
which is immediately followed by meiosis.
D) A diploid cell divides by mitosis to produce two diploid daughter cells, which then fuse to
produce a tetraploid cell.
12) The human X and Y chromosomes
A) are both present in every somatic cell of males and females alike.
B) are about the same size and have approximately the same number of genes.
C) are almost entirely homologous, despite their different names.
D) include genes that determine an individual’s sex.
13) Which of the following describes a karyotype?
A) a natural cellular arrangement of chromosomes in the nucleus
B) a display of all the cell types in an organism
C) organized images of a cell’s chromosomes
D) a display of a cell’s mitotic stages
14) Which of the following types of cells would be produced by meiosis?
A) a haploid animal cell
B) a diploid animal cell
C) a diploid plant cell
D) a diploid unicellular organism
15) Which of these is a way that the sexual life cycle increases genetic variation in a species?
A) by allowing crossing over
B) by allowing an increase in cell number
C) by increasing gene stability
D) by conserving chromosomal gene order
E) by decreasing mutation frequency
16) A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of
the following?
A) It must be human.
B) It must be an animal.
C) It must be sexually reproducing.
D) Its gametes must have 23 chromosomes.
17) A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with
42 chromosomes per cell is triploid, this cell would be expected to have which of the following?
A) 63 chromosomes in 31 1/2 pairs
B) 63 chromosomes in 21 sets of 3
C) 63 chromosomes, each with 3 chromatids
D) 21 chromosome pairs and 21 unique chromosomes
18) Which of the following statements best describes a karyotype?
A) a pictorial representation of all the genes for a species
B) a display of all of the chromosomes of a single cell
C) the combination of all the maternal and paternal chromosomes of a species
D) the collection of all the chromosomes in an individual organism
19) Which of the following cell types or organisms can utilize both mitosis and meiosis in the
correct circumstances?
A) a haploid animal cell
B) a diploid cell from a plant stem
C) any diploid animal cell
D) a unicellular alga
20) The somatic cells of a privet shrub each contain 46 chromosomes. To be as different as they
are from human cells, which have the same number of chromosomes, which of the following
must be true?
A) Privet cells cannot reproduce sexually.
B) Genes of privet chromosomes are significantly different from those in humans.
C) Privet shrubs must be metabolically more like animals than like other shrubs.
D) Genes on a particular privet chromosome, such as the X, must be on a different human
chromosome, such as number 18.
21) In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these
pairs, such as pair 14, which of the following do the two chromosomes of the pair have in
common?
A) length and position of the centromere only
B) length, centromere position, and staining pattern only
C) length, centromere position, staining pattern, and traits coded for by their genes
D) length, centromere position, staining pattern, and DNA sequences
22) The karyotype of one species of primate has 48 chromosomes. In a particular female, cell
division malfunctions, and she produces one of her eggs with an extra chromosome (25). The
most probable source of this error would be a mistake in which of the following?
A) mitosis in her ovary
B) telophase II of one meiotic event
C) telophase I of one meiotic event
D) either anaphase I or II
23) If a cell has completed the first meiotic division and is just beginning meiosis II, which of the
following statements describes the contents of this cell?
A) It has half the amount of DNA of the cell that began meiosis.
B) It has the same number of chromosomes, but each of them has different alleles than another
cell from the same meiosis.
C) It has half the chromosomes but twice the DNA of the originating cell.
D) It is identical in content to another cell from the same meiosis.
24) Which of the following events might result in a human zygote with 45 chromosomes?
A) an error in either egg or sperm meiotic anaphase
B) failure of the egg nucleus to be fertilized by the sperm
C) an error in the alignment of chromosomes on the metaphase plate
D) multiple crossover events during meiosis I
25) After telophase I of meiosis, the chromosomal makeup of each daughter cell is
A) diploid, and the chromosomes are each composed of a single chromatid.
B) diploid, and the chromosomes are each composed of two chromatids.
C) haploid, and the chromosomes are each composed of a single chromatid.
D) haploid, and the chromosomes are each composed of two chromatids.
26) How do cells at the completion of meiosis compare with cells that have replicated their DNA
and are just about to begin meiosis?
A) They have half the number of chromosomes and half the amount of DNA.
B) They have the same number of chromosomes and half the amount of DNA.
C) They have half the number of chromosomes and one-fourth the amount of DNA.
D) They have half the amount of cytoplasm and twice the amount of DNA.
27) When does the synaptonemal complex disappear?
A) late prophase of meiosis I
B) early anaphase of meiosis I
C) mid-prophase of meiosis II
D) late metaphase of meiosis II
28) Which of the following happens during meiosis I?
A) Homologous chromosomes of a pair are separated from each other.
B) The chromosome number per cell is conserved.
C) Sister chromatids are separated.
D) Four daughter cells are formed.
29) Chromatids are separated from each other during which of the following processes?
A) only during mitosis
B) only during meiosis I
C) only during meiosis II
D) during both mitosis and meiosis II
30) Which of the following events occurs in meiosis but not in mitosis?
A) chromosome replication
B) synapsis of chromosomes
C) production of daughter cells
D) condensation of chromatin
31) During mitosis or meiosis, sister chromatids are held together by proteins referred to as
cohesins. Such molecules must have which of the following properties?
A) They must persist throughout the cell cycle.
B) They must be removed before meiosis can begin.
C) They must be removed before sister chromatids or homologous chromosomes can separate.
D) They must be intact for nuclear envelope re-formation.
32) Which of the following structures is found in a pair of homologous chromosomes?
A) two single-stranded chromosomes that have synapsed
B) two sister chromatids that have synapsed
C) four sister chromatids
D) four unique chromosomes
33) When we see chiasmata under a microscope, that lets us know that which of the following
processes has occurred?
A) meiosis II
B) anaphase II
C) prophase I
D) separation of homologs
34) To visualize and identify meiotic cells at metaphase I with a microscope, what would you
look for?
A) sister chromatids of a replicated chromosome grouped at the poles
B) individual chromosomes all at the cell’s center
C) an uninterrupted spindle array
D) pairs of homologous chromosomes all aligned at the cell’s center
For the following question(s), match the key event of meiosis with the stages listed below.
I. prophase I V. prophase II
II. metaphase I VI. metaphase II
III. anaphase I VII. anaphase II
IV. telophase I VIII. telophase II
35) Homologous chromosomes are aligned at the equator of the spindle.
A) I
B) II
C) IV
D) VI
36) Synaptonemal complexes form or are still present.
A) I only
B) I and IV only
C) I and VIII only
D) I, II, III, and IV only
37) Centromeres of sister chromatids disjoin and chromatids separate.
A) III
B) IV
C) V
D) VII
38) The following question refers to the essential steps in meiosis described below.
1. formation of four new nuclei, each with half the chromosomes present in the parental nucleus
2. alignment of homologous chromosomes at the metaphase plate
3. separation of sister chromatids
4. separation of the homologs; no uncoupling of the centromere
5. synapsis; chromosomes moving to the middle of the cell in pairs
Which of the steps take(s) place in both mitosis and meiosis?
A) 3
B) 5
C) 2 and 3 only
D) 2, 3, and 5
39) For a species with a haploid number of 23 chromosomes, how many different combinations
of maternal and paternal chromosomes are possible for the gametes?
A) 23
B) 46
C) 460
D) approximately 8.4 million
40) Independent assortment of chromosomes during meiosis is a result of
A) the random and independent way in which each pair of homologous chromosomes lines up at
the metaphase plate during meiosis I.
B) the random nature of the fertilization of ova by sperm.
C) the random distribution of the sister chromatids to the two daughter cells during anaphase II.
D) the relatively small degree of homology shared by the X and Y chromosomes.
41) During which process does independent assortment of chromosomes occur?
A) during mitosis only
B) during meiosis I only
C) during meiosis II only
D) during mitosis and meiosis I
42) Which of the following statements best describes how often crossing over occurs in humans?
A) ~50 times per chromosome pair
B) ~2 times per meiotic cell
C) at least 1-3 times per chromosome pair
D) ~1 time per pair of sister chromatids
43) When homologous chromosomes cross over, what is the result?
A) Two sister chromatids get tangled, resulting in one altering the sequence of its DNA.
B) Two sister chromatids exchange identical pieces of DNA.
C) Specific proteins break the two strands of nonsister chromatids and re-join them.
D) Each of the four DNA strands of a homologous pair is broken, and the pieces are mixed.
10.2 Art Questions
Figure 10.1
1) Refer to the life cycles illustrated in Figure 10.1. Which of the life cycles is (are) typical for
animals?
A) I only
B) II only
C) III only
D) I and II
2) Refer to the life cycles illustrated in Figure 10.1. Which of the life cycles is (are) typical for
plants and some algae?
A) I only
B) II only
C) III only
D) I and II
3) Refer to the life cycles illustrated in Figure 10.1. Which of the life cycles is (are) typical for
most fungi and some protists?
A) I only
B) II only
C) III only
D) I and III
4) In part III of Figure 10.1, the progression of events corresponds to which of the following
series?
A) zygote, mitosis, gametophyte, mitosis, fertilization, zygote, mitosis
B) sporophyte, meiosis, spore, mitosis, gametophyte, mitosis, gametes, fertilization
C) fertilization, mitosis, multicellular haploid, mitosis, spores, sporophyte
D) gametophyte, meiosis, zygote, spores, sporophyte, zygote
5) In a life cycle such as that shown in part III of Figure 10.1, if the zygote’s chromosome
number is 10, which of the following will be true?
A) The sporophyte’s chromosome number per cell is 10 and the gametophyte’s is 5.
B) The sporophyte’s chromosome number per cell is 5 and the gametophyte’s is 10.
C) The sporophyte and gametophyte each have 10 chromosomes per cell.
D) The sporophyte and gametophyte each have 5 chromosomes per cell.
Figure 10.2
6) Refer to the drawings in Figure 10.2 of a single pair of homologous chromosomes as they
might appear during various stages of either mitosis or meiosis. Which diagram represents
anaphase I of meiosis?
A) I
B) II
C) IV
D) V
7) Refer to the drawings in Figure 10.2 of a single pair of homologous chromosomes as they
might appear during various stages of either mitosis or meiosis. Which diagram(s) represent(s)
anaphase II of meiosis?
A) II only
B) III only
C) V only
D) either II or V
Figure 10.3
8) You have isolated DNA from three different cell types of an organism, determined the relative
DNA content for each type, and plotted the results on the graph shown in Figure 10.3. Which
sample(s) of DNA might be from a skin cell arrested in G0 of the cell cycle?
A) I
B) II
C) either I or II
D) either I or III
9) You have isolated DNA from three different cell types of an organism, determined the relative
DNA content for each type, and plotted the results on the graph shown in Figure 10.3. Which
sample(s) might represent an animal cell in the G2 phase of the cell cycle?
A) I
B) II
C) III
D) both I and II
10) You have isolated DNA from three different cell types of an organism, determined the
relative DNA content for each type, and plotted the results on the graph shown in Figure 10.3.
Which sample(s) might represent a zygote?
A) I
B) II
C) III
D) either I or II
Figure 10.4
11) A certain (hypothetical) organism is diploid, has either blue or orange wings as the
consequence of one of its genes on chromosome 12, and has either long or short antennae as the
result of a second gene on chromosome 19, as shown in Figure 10.4. A certain female‘s number
12 chromosomes both have the blue gene and number 19 chromosomes both have the long gene.
As cells in her ovaries undergo meiosis, her resulting eggs (ova) may have which of the
following?
A) either two number 12 chromosomes with blue genes or two with orange genes
B) either two number 19 chromosomes with long genes or two with short genes
C) either one blue or one orange gene in addition to either one long or one short gene
D) one chromosome 12 with one blue gene and one chromosome 19 with one long gene
12) A certain (hypothetical) organism is diploid, has either blue or orange wings as the
consequence of one of its genes on chromosome 12, and has either long or short antennae as the
result of a second gene on chromosome 19, as shown in Figure 10.4. If a female of this species
has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene, and
has both number 19 chromosomes with short genes, she will produce which of the following egg
types?
A) only blue short gene eggs
B) only orange short gene eggs
C) one-half blue short and one-half orange short gene eggs
D) three-fourths blue short and one-fourth orange short gene eggs
13) A certain (hypothetical) organism is diploid, has either blue or orange wings as the
consequence of one of its genes on chromosome 12, and has either long or short antennae as the
result of a second gene on chromosome 19, as shown in Figure 10.4. A female with a paternal set
of one orange and one long gene chromosome and a maternal set composed of one blue and one
short gene chromosome is expected to produce which of the following types of eggs after
meiosis?
A) All eggs will have paternal types of gene combinations.
B) Half the eggs will have maternal and half will have paternal combinations.
C) Each egg has a one-fourth chance of having blue long, blue short, orange long, or orange
short combinations.
D) Each egg has a three-fourths chance of having blue long, one-fourth blue short, three-fourths
orange long, or one-fourth orange short combinations.
10.3 Scenario Questions
Please use the following information to answer the question(s) below.
There is a group of invertebrate animals called rotifers, among which a particular group of
species reproduces, as far as is known, only asexually. These rotifers, however, have survived a
long evolutionary history without evidence of having been overcome by excessive mutations.
1) Because the rotifers develop from eggs, but asexually, what can you predict?
A) The eggs and the zygotes are all haploid.
B) The animals are all males.
C) Although asexual, both males and females are found in nature.
D) No males can be found.
2) How is natural selection related to sexual reproduction as opposed to asexual reproduction?
A) Sexual reproduction results in many new gene combinations, some of which will lead to
differential reproduction.
B) Sexual reproduction results in the most appropriate and healthiest balance of two sexes in a
population.
C) Sexual reproduction results in the greatest number of new mutations.
D) Sexual reproduction allows the greatest number of offspring to be produced.
10.4 End-of-Chapter Questions
1) A human cell containing 22 autosomes and a Y chromosome is
A) a sperm.
B) an egg.
C) a zygote.
D) a somatic cell of a male.
2) Homologous chromosomes move toward opposite poles of a dividing cell during
A) mitosis.
B) meiosis I.
C) meiosis II.
D) fertilization.
3) If the DNA content of a diploid cell in the G1 phase of the cell cycle is represented by x, then
the DNA content of the same cell at metaphase of meiosis I would be
A) 0.25x.
B) 0.5x.
C) x.
D) 2x.
4) If we continued to follow the cell lineage from question 3, the DNA content of a cell at
metaphase of meiosis II would be
A) 0.25x.
B) 0.5x.
C) x.
D) 2x.