Chapter 13- Meiosis Flashcards
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 half of their nuclear 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.
In sexual reproduction, individuals transmit half of their nuclear genes to each of their offspring
Trichoplax adhaerens (Tp) is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. They move using cilia, and any “edge” can lead. Tp feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the
substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. Tp sperm cells have never been observed, nor have embryos past the 64-cell (blastula) stage.
If Tp sperm are observed by future researchers, how many chromosomes should be
found in a Tp sperm nucleus?
A) 2
B) 3
C) 6
D) 12
6
Which of these statements is correct?
A) In humans, each of the 23 maternal autosomes has a homologous paternal chromosome.
B) In humans, the twenty-second pair, the sex chromosomes, determines whether the person is female (XY) or male (XX).
C) Single, haploid (2n) sets of chromosomes in ovum and sperm unite during fertilization, forming a diploid (4n), single-celled zygote.
D) At sexual maturity, ovaries and testes produce haploid gametes by meiosis.
At sexual maturity, ovaries and testes produce haploid gametes by meiosis
A triploid cell contains sets of 3 homologous 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 pairs
B) 63 chromosomes in 21 sets of 3
C) 63 chromosomes, each with 3 chromatids
D) 21 chromosome pairs and 21 unique chromosomes
63 chromosomes in 21 sets of 3
If a cell has completed meiosis I 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 formed from the same meiosis I event.
It has half the amount of DNA as the cell that began meiosis.
The somatic cells of a privet shrub each contain 46 chromosomes. How do privet chromosomes differ from the chromosomes of humans, who also have 46?
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 from 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.
Genes of privet chromosomes are significantly different from those in humans.
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 pairhave 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) They have nothing in common except that they are X-shaped.
length, centromere position, staining pattern, and traits coded for by their genes
How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I? They have ________.
A) twice the amount of cytoplasm and half the amount of DNA.
B) half the number of chromosomes and half the amount of DNA.
C) the same number of chromosomes and half the amount of DNA.
D) half the number of chromosomes and one-fourth the amount of DNA.
E) half the amount of cytoplasm and twice the amount of DNA
half the number of chromosomes and one-fourth the amount of DNA.
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
haploid, and the chromosomes are each composed of two chromatids
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
late prophase of meiosis I
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 remains the same.
C) Sister chromatids are separated.
D) Four daughter cells are formed.
E) Cohesins are cleaved at the centromeres.
Homologous chromosomes of a pair are separated from each other.
Sister chromatids separate from each other during ________.
A) mitosis only
B) meiosis I only
C) meiosis II only
D) mitosis and meiosis I
E) mitosis and meiosis II
mitosis and meiosis II
Independent assortment of chromosomes occurs during ________.
A) mitosis only
B) meiosis I only
C) meiosis II only
D) mitosis and meiosis I
E) mitosis and meiosis II
meiosis I only
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 chromosomes
synapsis of chromosomes
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
at most, 2 alleles for that gene
Whether during mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesins. Such molecules must ________.
A) persist throughout the cell cycle
B) be removed before meiosis can begin
C) be removed before sister chromatids can separate
D) reattach to chromosomes during G1
E) be intact for nuclear envelope re-formation
be removed before sister chromatids can separate
Somatic cells of roundworms have four individual chromosomes per cell. How many chromosomes would you expect to find in an ovum from a roundworm?
A) four
B) two
C) eight
D) a diploid number
two
Which of the following can occur by the process of meiosis but not mitosis?
A) Haploid cells fuse to form diploid cells.
B) Haploid cells multiply into more haploid cells.
C) Diploid cells form haploid cells.
D) A diploid cell combines with a haploid cell.
Diploid cells form haploid cells.
In meiosis, homologous chromosomes are separated during ________.
A) anaphase II
B) prophase I
C) mitosis
D) anaphase I
anaphase I
What is a major difference between meiosis II and mitosis in a diploid animal?
A) Homologs align on the metaphase plate in meiosis II.
B) Sister chromatids separate in mitosis, and homologs separate in meiosis II.
C) Meiosis II occurs in a haploid cell, and mitosis occurs in diploid cells.
D) Crossover takes place in meiosis II.
Meiosis II occurs in a haploid cell, and mitosis occurs in diploid cells.
What is a major difference between mitosis and meiosis I in a diploid organism?
A) Sister chromatids separate in mitosis; homologous pairs of chromosomes separate in
meiosis I.
B) Sister chromatids separate in mitosis; homologous pairs of chromosomes separate in
meiosis II.
C) DNA replication takes place prior to mitosis, but not before meiosis I.
D) Only meiosis I results in daughter cells that contain identical genetic information.
Sister chromatids separate in mitosis; homologous pairs of chromosomes separate in
meiosis I.
Crossing over normally takes place during which of the following processes?
A) meiosis II
B) meiosis I
C) mitosis
D) mitosis and meiosis II
meiosis I
In the snail Pomacea patula catemacensis, n = 13. What is the diploid number for this organism?
A) 13
B) 26
C) 52
D) 7
26
What phase of meiosis is seen in the accompanying figure?
A) metaphase I
B) metaphase II
C) anaphase I
D) anaphase II
anaphase I
Homologous chromosomes ________.
A) are identical
B) carry information for the same traits
C) carry the same alleles
D) align on the metaphase plate in meiosis II
carry information for the same traits
For the duration of meiosis I, each chromosome ________.
A) is paired with a homologous chromosome
B) consists of two sister chromatids joined by a centromere
C) consists of a single strand of DNA
D) is joined with its homologous pair to form a synaptonemal complex
consists of two sister chromatids joined by a centromere
The egg of a fruit fly has 4 individual chromosomes. How many chromosomes are in a somatic cell of a fruit fly?
A) 4
B) 2
C) 8
D) 16
8
Homologous pairs of chromosomes align opposite to each other at the equator of a
cell during ________.
A) metaphase of mitosis
B) metaphase I of meiosis
C) telophase II of meiosis
D) metaphase II of meiosis
metaphase I of meiosis
Centromeres split and sister chromatids migrate to opposite poles in ________ of
meiosis.
A) anaphase I
B) telophase I
C) anaphase II
D) telophase II
anaphase II
The chromosome number of hexaploid wheat, Triticum aestivum, can be
represented as ________.
A) n
B) 2n
C) 4n
D) 6n
6n
Hexaploid wheat was produced synthetically by He and co-workers. They mated the diploid species, A. tauschii, and the tetraploid species, T. turgidum. Which of the following is an accurate statement about the relative contribution of each parent to the
genome of the hexaploid offspring?
A) Each parent contributed equally to the genome of the offspring.
B) Aegilops tauschii contributed four chromosomes by failing to complete meiosis after chromosome replication, and T. turgidum contributed two chromosomes.
C) Aegilops tauschii contributed two sets of chromosomes, and T. turgidum contributed four sets of chromosomes.
D) The hexaploid number appeared following mitosis with no subsequent cell division.
Aegilops tauschii contributed two sets of chromosomes, and T. turgidum contributed
four sets of chromosomes.
When does DNA replication take place regarding meiosis? DNA replication ________.
A) does not take place in cells destined to undergo meiosis
B) occurs before meiosis I begins
C) occurs between meiosis I and meiosis II
D) occurs during prophase I
occurs before meiosis I begins
Quaking aspen can send out underground stems for asexual reproduction. Sexual reproduction is not as common, but when it does happen, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems?
A) 9
B) 10
C) 19
D) 38
38
The diploid number of a roundworm species is 4. Assuming there is no crossover, and random segregation of homologs during meiosis, how many different possible combinations of chromosomes might there be in the offspring?
A) 4
B) 8
C) 16
D) 64
16
If meiosis produces haploid cells, how is the diploid number restored for those
organisms that spend most of their life cycle in the diploid state?
A) DNA replication
B) reverse transcription
C) synapsis
D) fertilization
fertilization
Which of the following would enable you to detect aneuploidy?
A) autosomy
B) karyotyping
C) syngamy
D) synapsis
karyotyping
When we first see chiasmata under a microscope, we know that ________.
A) asexual reproduction has occurred
B) meiosis II has occurred
C) anaphase II has occurred
D) prophase I is occurring
E) separation of homologs has occurred
prophase I is occurring
What makes sexually reproduced offspring genetically different from their parents?
A) genetic recombination during meiosis
B) genetic recombination during mitosis
C) crossing over during mitosis
D) Sexual reproduction does not produce genetically different offspring.
genetic recombination during meiosis
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) backtracking through her previous experiments to obtain another plant with the same traits
B) breeding this plant with another plant with much weaker traits
C) cloning the plant
D) forcing the plant to self-pollinate to obtain an identical one
E) adding nitrogen to the soil of the offspring of this plant so the desired traits continue
cloning the plant
Independent assortment of chromosomes is a result of ________.
A) the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I
B) the random combinations of eggs and sperm during fertilization
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 diverse combination of alleles that may be found within any given chromosome
the random way each pair of homologous chromosomes lines up at the metaphase
plate during meiosis I
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) about 1000
D) about 8 million
E) about 70 trillion
about 8 million
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 the figure.
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
one chromosome 12 with one blue gene and one chromosome 19 with one long gene
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.
Each egg has a one-fourth chance of having either blue long, blue short, orange
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
one-half blue short and one-half orange short gene eggs
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. 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 fertile males can be found.
No fertile males can be found.
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
16
Which is the smallest unit containing the entire human genome?
A) one male somatic cell
B) one human chromosome
C) all of the DNA in all of the cells of one human
D) all of the DNA in all of the cells of the entire human population
E) one human gamete
one male somatic cell
The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. Diversity in this species may be generated by mutations and ________.
A) crossing over
B) independent assortment
C) crossing over and independent assortment
D) nothing else
crossing over and independent assortment
Asexual reproduction occurs during ________.
A) meiosis
B) mitosis
C) fertilization
D) chromosome exchange between organisms of different species
mitosis
The fastest way for organisms to adapt to a changing environment involves ________.
A) mutation
B) asexual reproduction
C) sexual reproduction
sexual reproduction
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) failure of an egg to complete meiosis II
D) incomplete cytokinesis during spermatogenesis after meiosis I
an error in either egg or sperm meiotic anaphase
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
either anaphase I or II
Turner syndrome is characterized by the presence of only one X chromosome in an affected female. Which of the following accurately describes Turner syndrome?
A) monosomy
B) trisomy
C) 2n + 1
D) 47,XXX aneuploidy
monosomy
A triploid individual ________.
A) is unable to undergo normal meiosis
B) is unable to undergo mitosis
C) produces offspring with an even number of chromosome sets (for example,
tetraploid, hexaploid)
D) has an additional stage in meiosis (meiosis I, meiosis II, and meiosis III)
is unable to undergo normal meiosis
What is the most common source of the extra chromosome 21 in an individual with Down syndrome?
A) nondisjunction in the mother
B) nondisjunction in the father
C) duplication of chromosome 21
D) deletion in either parent
nondisjunction in the mother
A couple has a child with Down syndrome. The mother is 39 years old at the time of delivery. Which of the following is the most probable cause of the child’s condition?
A) The woman inherited this tendency from her parents.
B) The mother had a chromosomal duplication.
C) One member of the couple underwent nondisjunction in somatic cell production.
D) The mother most likely underwent nondisjunction during gamete production.
The mother most likely underwent nondisjunction during gamete production.
Which of the following could be considered an evolutionary advantage of asexual reproduction in plants?
A) increased success of progeny in a stable environment
B) increased agricultural productivity in a rapidly changing environment
C) maintenance and expansion of a large genome
D) production of numerous progeny
E) increased ability to adapt to a change in the environment
increased success of progeny in a stable environment
Plants produce more seeds when they reproduce asexually than sexually. Yet most plants reproduce sexually in nature. What is the probable explanation for the prevalence of sexual reproduction? Sexual reproduction ________.
A) is more energy efficient than asexual reproduction
B) ensures genetic continuity from parents to offspring
C) mixes up alleles, contributing to variation in a species
D) is not dependent on other agents of pollination
mixes up alleles, contributing to variation in a species
An advantage of asexual reproduction is that it ________.
A) allows the species to endure long periods of unstable environmental conditions
B) enhances genetic variability in the species
C) enables the species to rapidly colonize habitats that are favorable to that species
D) produces offspring that respond effectively to new pathogens
E) allows a species to easily rid itself of harmful mutations
enables the species to rapidly colonize habitats that are favorable to that species
Genetic mutations in asexually reproducing organisms lead to more evolutionary change than do genetic mutations in sexually reproducing ones because ________.
A) asexually reproducing organisms, but not sexually reproducing organisms, pass all mutations on to their offspring
B) asexually reproducing organisms devote more time and energy to the process of reproduction than do sexually reproducing organisms
C) sexually reproducing organisms can produce more offspring in a given time than can asexually reproducing organisms
D) more genetic variation is present in organisms that reproduce asexually than is present in those that reproduce sexually
E) asexually reproducing organisms have more dominant genes than organisms that reproduce sexually
asexually reproducing organisms, but not sexually reproducing organisms, pass all mutations on to their offspring
Asexual reproduction results in greater reproductive success than does sexual reproduction when ________.
A) pathogens are rapidly diversifying
B) a species has accumulated numerous deleterious mutations
C) there is some potential for rapid overpopulation
D) a species is expanding into diverse geographic settings
E) a species is in stable and favorable environments
a species is in stable and favorable environments
Sexual reproduction ________.
A) allows animals to conserve resources and reproduce only during optimal conditions
B) can produce diverse phenotypes that may enhance survival of a population in a changing environment
C) yields more numerous offspring more rapidly than is possible with asexual reproduction
D) enables males and females to remain isolated from each other while rapidly colonizing habitats
E) guarantees that both parents will provide care for each offspring
can produce diverse phenotypes that may enhance survival of a population in a changing environment
All individuals of a particular species of whiptail lizards are females. Their reproductive efforts depend on ________.
A) fertilization of their eggs by males of other lizard species
B) gonadal structures that only undergo mitosis
C) meiosis followed by a doubling of the chromosomes in eggs
D) budding prior to the development of a sexual phenotype
E) fragmentation via autolysis
meiosis followed by a doubling of the chromosomes in eggs
