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.
E) Add nitrogen to the soil of the offspring of this plant
so the desired traits continue.
Answer: C
The human genome is minimally contained in which of the following?
A) every human cell
B) each human chromosome
C)
the entire DNA of a single human
D) the entire human population
E) each human gene
Answer: A
In the human species, all somatic cells have 46 chromosomes. Which of
the following can also be true?
A) A plant species (privet
shrubs) has 46 chromosomes per cell.
B) Some adult humans have
69 chromosomes per cell.
C) Some adult humans have 23
chromosomes per cell.
D) A certain fungal species has only one
chromosome per cell.
E) A certain bacterial species has 23 chromosomes.
Answer: A
Which of the following is a true statement about sexual vs. 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) Sexual
reproduction requires that parents be diploid.
E) Asexual
reproduction produces only haploid offspring.
Answer: B
Which of the following defines a genome?
A) representation of
a complete set of a cell's polypeptides
B) the complete set of
an organism's polypeptides
C) the complete set of a species'
polypeptides
D) a karyotype
E) the complete set of an
organism's genes
Answer: E
At which stage of mitosis are chromosomes usually photographed in the
preparation of a karyotype?
A) prophase
B) metaphase
C) anaphase
D) telophase
E) interphase
Answer: B
The human X and Y chromosomes
A) are both present in every
somatic cell of males and females alike.
B) are of
approximately equal size and number of genes.
C) are almost
entirely homologous, despite their different names.
D) include
genes that determine an individual's sex.
E) include only genes
that govern sex determination.
Answer: D
Which of the following is true of a species that has a chromosome
number of 2n = 16?
A) The species is diploid with 32
chromosomes per cell.
B) The species has 16 sets of chromosomes
per cell.
C) Each cell has eight homologous pairs.
D)
During the S phase of the cell cycle there will be 32 separate
chromosomes.
E) A gamete from this species has four chromosomes.
Answer: C
Eukaryotic sexual life cycles show tremendous variation. Of the
following elements, which 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
E) I, II, III, IV, and V
Answer: C
Which of these statements is false?
A) In humans, each of the
22 maternal autosomes has a homologous paternal chromosome.
B)
In humans, the 23rd pair, the sex chromosomes, determines whether the
person is female (XX) or male (XY).
C) Single, haploid (n) sets
of chromosomes in ovum and sperm unite during fertilization, forming a
diploid (2n), single-celled zygote.
D) At sexual maturity,
ovaries and testes produce diploid gametes by meiosis.
E)
Sexual life cycles differ with respect to the relative timing of
meiosis and fertilization.
Answer: C
Referring to a plant's sexual life cycle, which of the following
terms describes the process that leads directly to the formation of
gametes?
A) sporophyte meiosis
B) gametophyte mitosis
C) gametophyte meiosis
D) sporophyte mitosis
E)
alternation of generations
Answer: B
Which of the following is an example of alternation of generations?
A) A grandparent and grandchild each have dark hair, but the
parent has blond hair.
B) A diploid plant (sporophyte)
produces, by meiosis, a spore that gives rise to a multicellular,
haploid pollen grain (gametophyte).
C) A diploid animal
produces gametes by meiosis, and the gametes undergo fertilization to
produce a diploid zygote.
D) A haploid mushroom produces
gametes by mitosis, and the gametes undergo fertilization, which is
immediately followed by meiosis.
E) A diploid cell divides by
mitosis to produce two diploid daughter cells, which then fuse to
produce a tetraploid cell.
Answer: B
The karyotype of one species of primate has 48 chromosomes. In a
particular female, cell division goes awry 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) metaphase I of one meiotic event
C)
telophase II of one meiotic event
D) telophase I of one meiotic
event
E) either anaphase I or II
Answer: E
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 a primate.
C) It must be an animal.
D) It must be sexually reproducing.
E) Its gametes must have 23 chromosomes.
Answer: E
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 three chromatids
D) 21
chromosome pairs and 21 unique chromosomes
Answer: B
A karyotype results from which of the following?
A) a natural
cellular arrangement of chromosomes in the nucleus
B) an
inherited ability of chromosomes to arrange themselves
C) the
ordering of human chromosome images
D) the cutting and pasting
of parts of chromosomes to form the standard array
E) the
separation of homologous chromosomes at metaphase I of meiosis
Answer: C
Which of the following best describes a karyotype?
A) a
pictorial representation of all the genes for a species
B) a
display of each 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
E) a photograph of all the cells with missing or extra chromosomes
Answer: B
If a cell has completed the first meiotic division and is just
beginning meiosis II, which of the following is an appropriate
description of its contents?
A) It has half the amount of DNA
as 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 has one-fourth the DNA
and one-half the chromosomes as the originating cell.
E) It is
identical in content to another cell from the same meiosis.
Answer: A
Which of the following 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 plantlike protist
E) an archaebacterium
Answer: D
Which of the following 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) fertilization of a 23 chromosome human egg by a 22
chromosome sperm of a closely related species
D) an error in
the alignment of chromosomes on the metaphase plate
E) lack of
chiasmata in prophase I
Answer: A
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) Privet sex cells
have chromosomes that can synapse with human chromosomes in the
laboratory.
C) Genes of privet chromosomes are significantly
different than those in humans.
D) Privet shrubs must be
metabolically more like animals than like other shrubs.
E)
Genes on a particular privet chromosome, such as the X, must be on a
different human chromosome, such as number 18.
Answer: C
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.
E) They have nothing in common except they are X-shaped.
Answer: C
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.
E) tetraploid,
and the chromosomes are each composed of two chromatids.
Answer: D
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 twice the amount of cytoplasm and half the amount of DNA.
B) They have half the number of chromosomes and half the amount
of DNA.
C) They have the same number of chromosomes and half
the amount of DNA.
D) They have half the number of chromosomes
and one-fourth the amount of DNA.
E) They have half the amount
of cytoplasm and twice the amount of DNA.
Answer: D
When does the synaptonemal complex disappear?
A) late prophase
of meiosis I
B) during fertilization or fusion of gametes
C) early anaphase of meiosis I
D) mid-prophase of
meiosis II
E) late metaphase of meiosis II
Answer: A
Which of the following happens at the conclusion of meiosis I?
A) Homologous chromosomes are separated.
B) The chromosome
number per cell is conserved.
C) Sister chromatids are
separated.
D) Four daughter cells are formed.
E) The
sperm cells elongate to form a head and a tail end.
Answer: A
A cell divides to produce two daughter cells that are genetically
different.
A) The statement is true for mitosis only.
B)
The statement is true for meiosis I only.
C) The statement is
true for meiosis II only.
D) The statement is true for mitosis
and meiosis I.
E) The statement is true for mitosis and meiosis II.
Answer: B
Chromatids are separated from each other.
A) The statement is
true for mitosis only.
B) The statement is true for meiosis I
only.
C) The statement is true for meiosis II only.
D)
The statement is true for mitosis and meiosis I.
E) The
statement is true for mitosis and meiosis II.
Answer: E
Independent assortment of chromosomes occurs.
A) The statement
is true for mitosis only.
B) The statement is true for meiosis
I only.
C) The statement is true for meiosis II only.
D)
The statement is true for mitosis and meiosis I.
E) The
statement is true for mitosis and meiosis II.
Answer: B
Which of the following occurs in meiosis but not in mitosis?
A) chromosome replication
B) synapsis of chromosomes
C)
production of daughter cells
D) alignment of chromosomes at the
equator
E) condensation of chromatin
Answer: B
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) a haploid number of
9 chromosomes
E) up to, but not more than, 18 different traits
Answer: A
Whether 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 anaphase can
occur.
D) They must reattach to chromosomes during G₁.
E) They must be intact for nuclear envelope reformation.
Answer: C
Experiments with cohesins have found that
A) cohesins are
protected from destruction throughout meiosis I and II.
B)
cohesins are cleaved from chromosomes at the centromere before
anaphase I.
C) cohesins are protected from cleavage at the
centromere during meiosis I.
D) a protein cleaves cohesins
before metaphase I.
E) a protein that cleaves cohesins would
cause cellular death.
Answer: C
A tetrad includes which of the following sets of DNA strands?
A) two single-stranded chromosomes that have synapsed
B) two
sets of sister chromatids that have synapsed
C) four sets of
sister chromatids
D) four sets of unique chromosomes
E)
eight sets of sister chromatids
Answer: B
When we see chiasmata under a microscope, that lets us know which of
the following has occurred?
A) asexual reproduction
B)
meiosis II
C) anaphase II
D) prophase I
E)
separation of homologs
Answer: D
To view and analyze human chromosomes in a dividing cell, which of
the following is/are required?
A) electron microscope
B)
radioactive staining
C) fluorescent staining
D) DNA
stain and a light microscope
E) a stain particular to human cells
Answer: D
To visualize and identify meiotic cells at metaphase with a
microscope, what would you look for?
A) sister chromatids
grouped at the poles
B) individual chromosomes all at the
cell's center
C) an uninterrupted spindle array
D) the
synaptonemal complex
E) tetrads all aligned at the cell's center
Answer: E
For the following question, 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
38) Tetrads
of chromosomes are aligned at the equator of the spindle; alignment
determines independent assortment.
A) I
B) II
C)
IV
D) VI
E) VIII
Answer: B
For the following question, 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
39)
Synaptonemal complexes form or are still present.
A) I only
B) I and IV only
C) I and VIII only
D) II and VI
only
E) I, II, III, and IV only
Answer: A
For the following question, 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
40)
Centromeres of sister chromatids disjoin and chromatids separate.
A) II
B) III
C) IV
D) V
E) VII
Answer: E
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 tetrads 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
41) Which of the steps takes place
in both mitosis and meiosis?
A) 2
B) 3
C) 5
D) 2 and 3 only
E) 2, 3, and 5
Answer: B
How does the sexual life cycle increase the genetic variation in a
species?
A) by allowing crossing over
B) by allowing
fertilization
C) by increasing gene stability
D) by
conserving chromosomal gene order
E) by decreasing mutation frequency
Answer: A
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) 920
E) about 8 million
Answer: E
Independent assortment of chromosomes 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.
E) the random and
independent way in which each pair of homologous chromosomes lines up
at the metaphase plate during meiosis I, the random nature of the
fertilization of ova by sperm, the random distribution of the sister
chromatids to the two daughter cells during anaphase II, and the
relatively small degree of homology shared by the X and Y chromosomes.
Answer: A
Which of the following best describes the frequency of crossing over
in mammals?
A) ~50 per chromosome pair
B) ~2 per meiotic
cell
C) at least 1-2 per chromosome pair
D) ~1 per pair
of sister chromatids
E) a very rare event among hundreds of cells
Answer: C
When homologous chromosomes crossover, what occurs?
A) Two
chromatids get tangled, resulting in one re-sequencing its DNA.
B) Two sister chromatids exchange identical pieces of DNA.
C)
Specific proteins break the two strands and re-join them with their
homologs.
D) Each of the four DNA strands of a tetrad is broken
and the pieces are mixed.
E) Maternal alleles are
"corrected" to be like paternal alleles and vice versa.
Answer: C
Which of the life cycles is typical for animals?
A) I only
B) II only
C) III only
D) I and II
E) I
and III
Answer: A
Which of the life cycles is typical for plants and some algae?
A) I only
B) II only
C) III only
D) I and II
E) I and III
Answer: C
Which of the life cycles is typical for most fungi and some protists?
A) I only
B) II only
C) III only
D) I and
II
E) I and III
Answer: B
In part III of Figure 13.1, 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
E) meiosis, fertilization, zygote,
mitosis, adult, meiosis
Answer: B
In a life cycle such as that shown in part III of Figure 13.1, 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.
E)
The sporophyte and gametophyte each have 20 chromosomes per cell.
Answer: A
Which diagram represents anaphase I of meiosis?
A) I
B)
II
C) IV
D) V
E) VI
Answer: A
Which diagram(s) represent anaphase II of meiosis?
A) II only
B) III only
C) IV only
D) V only
E) either
II or V
Answer: D
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 13.3. Refer to the graph to answer the following questions.
Which sample of DNA might be from a nerve cell arrested in G0 of
the cell cycle?
A) I
B) II
C) III
D)
either I or II
E) either I or III
Answer: A
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 13.3. Refer to the graph to answer the following questions.
Which sample might represent an animal cell in the G2 phase of the
cell cycle?
A) I
B) II
C) III
D) both I
and II
E) either II or III
Answer: B
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 13.3. Refer to the graph to answer the following questions.
Which sample might represent a zygote?
A) I
B) II
C) III
D) either I or II
E) either II or III
Answer: A
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 13.4.
57) 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
Answer: D
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 13.4.
58) 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 long and one-fourth orange
short gene eggs
E) three-fourths blue short and one-fourth
orange short gene eggs
Answer: C
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 13.4.
59) A female
with a paternal set of one orange and one long gene chromosome and a
maternal set comprised 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 maternal types of gene
combinations.
B) All eggs will have paternal types of gene
combinations.
C) Half the eggs will have maternal and half will
have paternal combinations.
D) Each egg has a one-fourth chance
of having either blue long, blue short, orange long, or orange short
combinations.
E) 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.
Answer: D
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.
60) Since 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 hermaphrodites.
C) While asexual, both males and females are found in nature.
D) All males can produce eggs.
E) No males can be found.
Answer: E
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.
61) Assuming that the eggs are diploid,
tetraploid, or partially tetraploid, what mechanism may still occur
without fertilization?
A) meiosis in each generation
B)
meiosis in every second generation
C) independent assortment of
maternal and paternal chromosomes
D) meiosis in times of
adverse environmental conditions
E) crossing over of homologs
Answer: E
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.
62) In these asexual rotifers, how does
variation occur without meiosis and fertilization?
A) The
rotifers have evolved a different mechanism to exchange DNA.
B)
Rotifers must produce haploid spores.
C) Variation is caused by
mutation and maintained by selection.
D) Some rotifers must
selectively lose chromosomes.
E) Rotifers must live only in
specialized environments.
Answer: C
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 the population.
C) Sexual reproduction results in the greatest number of new
mutations.
D) Sexual reproduction allows the greatest number of
offspring to be produced.
E) Sexual reproduction utilizes far
less energy than asexual reproduction.
Answer: D
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.
E) a somatic cell of a female.
Answer: A
Which life cycle stage is found in plants but not animals?
A)
gamete
B) zygote
C) multicellular diploid
D)
multicellular haploid
E) unicellular diploid
Answer: D
Homologous chromosomes move toward opposite poles of a dividing cell
during
A) mitosis.
B) meiosis I.
C) meiosis II.
D) fertilization.
E) binary fission.
Answer: B
Meiosis II is similar to mitosis in that
A) sister chromatids
separate during anaphase.
B) DNA replicates before the
division.
C) the daughter cells are diploid.
D)
homologous chromosomes synapse.
E) the chromosome number is reduced.
Answer: A
If the DNA content of a diploid cell in the G₁ phase of the cell
cycle is 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.
E) 4x.
Answer: D
If the DNA content of a diploid cell in the G₁ phase of the cell
cycle is x, then the DNA content of a single cell at metaphase of
meiosis II would be
A) 0.25x.
B) 0.5x.
C) x.
D) 2x.
E) 4x.
Answer: C
How many different combinations of maternal and paternal chromosomes
can be packaged in gametes made by an organism with a diploid number
of 8(2n = 8)?
A) 2
B) 4
C) 8
D) 16
E) 32
Answer: D