Chapter 10 MCQS Flashcards

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.

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

Which is the smallest unit containing the entire human genome?
A) one human somatic cell
B) one human chromosome
C) all of the DNA of one human
D) the entire human population
E) one human gene

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

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.

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

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.

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

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.

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

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.

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

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

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

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.

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

Mitosis is commonly found in all of the following except
A) a haploid animal cell.
B) a diploid animal cell.
C) a haploid plant cell.
D) a diploid plant cell.

Which of these is 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) the appearance of an organism
E) a display of a cell’s mitotic stages

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.
E) are called autosomes.

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.

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.

To view and analyze human chromosomes in a dividing cell, which of the following is (are)
required?
A) a scanning electron microscope
B) radioactive staining
C) fluorescent staining and a transmission electron microscope
D) DNA staining and a light microscope
E) a stain particular to human cells

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

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.

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

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.

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.

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

Which of the following happens at the conclusion of 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.
E) Cohesins are cleaved at the centromeres.

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.

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

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 sister chromatids or homologous chromosomes can separate.
D) They must reattach to chromosomes during G1.
E) They must be intact for nuclear envelope re-formation.

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.

34) A pair of homologous chromosomes includes which of the following sets of DNA strands?
A) two single-stranded chromosomes that have synapsed
B) two sister chromatids that have synapsed
C) four sister chromatids
D) four unique chromosomes
E) eight sister chromatids

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

To visualize and identify meiotic cells at metaphase 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) the synaptonemal complex
E) pairs of homologous chromosomes all aligned at the cell's center

For the following questions, 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
37) Homologous chromosomes are aligned at the equator of the spindle.
A) I
B) II
C) IV
D) VI
E) VIII

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

Centromeres of sister chromatids disjoin and chromatids separate.
A) II
B) III
C) IV
D) V
E) VII