Week 8-9 Flashcards
Privet shrubs and humans each have a diploid number of 46
chromosomes per cell. Why are the two species so dissimilar?
A. Privet chromosomes undergo only mitosis.
B. Privet chromosomes are shaped differently.
C. Human chromosomes have genes grouped together differently.
D. The two species have appreciably different genes.
E. Privets do not have sex chromosomes.
D. The two species have appreciably different genes.
Why is it more practical to prepare karyotypes by viewing somatic
diploid cells rather than haploid gametes?
A. Only diploid cells have condensed chromosomes.
B. Only diploid cells have all the organism’s chromosomes.
C. Haploid cells are too small.
D. Haploid cells are not easily available.
B. Only diploid cells have all the organism’s chromosomes.
Diploid (2n) cells may undergo either mitosis or meiosis. Can
haploid (n) cells?
A. Haploid cells can undergo both mitosis and meiosis.
B. Haploid cells can undergo mitosis but not meiosis.
C. Haploid cells can undergo meiosis but not mitosis.
D. Haploid cells can undergo neither mitosis nor meiosis.
B. Haploid cells can undergo mitosis but not meiosis.
A haploid set of unreplicated chromosomes (n = 4) of the fruit fly
Drosophila melanogaster has a mass of 0.14 p g. What is the mass of
DNA in a single Drosophila cell at the end of telophase II?
A. 0.14 p g
B. 0.28 p g
C. 0.42 p g
D. 0.56 p g
A. 0.14 p g
A homozygous dominant purple-flowered and homozygous
recessive white-flowered pea plants have the following genetic
makeup:
A. PP and pp
B. pp and PP
C. Pp and Pp
D. Pp and pp
A. PP and pp
Prophase I of meiosis is generally the longest phase of meiosis.
Why might this be?
A. DNA replication
B. synapsis and recombination
C. independent assortment
D. gamete formation
B. synapsis and recombination
Assume there are 50 people in the classroom. Theoretically
speaking, what is the maximum number of different alleles there
could be at a hypothetical autosomal locus?
A. 2
B. 3
C. 50
D. 100
D. 100
Pea plants were particularly well suited for use in Mendel’s breeding
experiments for all of the following reasons except that Fill in the blank .
A. peas show easily observed variations in a number of characters, such
as pea shape and flower color
B. it is possible to control matings between different pea plants
C. it is possible to obtain large numbers of progeny from any given cross
D. peas have an unusually long generation time
E. many of the observable characters that vary in pea plants are
controlled by single genes
D. peas have an unusually long generation time
Imagine crossing a pea heterozygous at the loci for flower color (P
p) and seed color (Y y) with a second pea homozygous for flower
color (p p) and seed color (y y). What genotypes of gametes will the
first pea produce?
A. two gamete types: p p and P p
B. two gamete types: p Y and P y
C. four gamete types: p Y, p y, P Y, and P y
D. four gamete types: P p, Y y, p p, P P
C. four gamete types: p Y, p y, P Y, and P y
A cross between homozygous purple-flowered and homozygous
white-flowered pea plants results in offspring with purple flowers.
This demonstrates Fill in the blank .
A. the blending model of genetics
B. true breeding
C. dominance
D. a dihybrid cross
E. the mistakes made by Mendel
C. dominance
Consider a family in which a man, age 47, has just been diagnosed with
Huntington’s disease, a late-onset disease that is caused by a dominant
autosomal allele (the man is a heterozygote). His daughter, age 25, has a
2-year-old son. No one else in the family has the disease. What is the
probability that the 2-year-old son will contract the disease?
A. 0%
B. 25%
C. 50%
D. 75%
E. 100%
B. 25%
Why did the improvement of microscopy techniques in the late 1800s set
the stage for the emergence of modern genetics?
A. It revealed new and unanticipated features of Mendel’s pea plant
varieties.
B. It allowed the study of meiosis and mitosis, revealing parallels between
behaviors of the Mendelian concept of the gene and the
movement/pairing of chromosomes.
C. It allowed scientists to see the nucleotide sequence of D N A.
D. It led to the discovery of mitochondria.
E. It showed genes functioning to direct the formation of enzymes.
B. It allowed the study of meiosis and mitosis, revealing parallels between
behaviors of the Mendelian concept of the gene and the
movement/pairing of chromosomes.
Which statement best describes the relationship between recombination
frequency and the physical distance of genes on chromosomes?
A. There is no relationship. All genes have random recombination
frequencies.
B. There is no relationship. All genes have the same, fixed recombination
frequencies.
C. The farther apart two genes are, the higher the recombination
frequency.
D. The closer together two genes are, the higher the recombination
frequency.
C. The farther apart two genes are, the higher the recombination
frequency.
Chromatids are __________.
a) identical copies of each other if they are part of the same chromosome
b) held together by the centrioles
c) the bacterial equivalent of eukaryotic chromosomes
d) composed of RNA
e) found only in aberrant chromosomes
a) identical copies of each other if they are part of the same chromosome
If a cell contains 60 chromatids at the start of mitosis, how many chromosomes will be found in each daughter cell at the completion of the cell cycle?
a) 15
b) 30
c) 45
d) 60
e) 120
b) 30
During interphase, the genetic material of a typical eukaryotic cell is __________.
a) transported through the nuclear pores
b) condensed and the chromosomes are often visible under the light microscope
c) attached to microtubule spindle fibers
d) dispersed in the nucleus as long strands of chromatin
e) dispersed in the cytoplasm as long strands of chromatin
d) dispersed in the nucleus as long strands of chromatin
Which of the following does not occur during mitosis?
a) alignment of chromosomes along the cell’s equator
b) the movement of chromosomes to opposite poles
c) separation of chromatids
d) replication of chromosomes
e) condensation of chromatin
d) replication of chromosomes
In telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in __________.
a) anaphase
b) interphase
c) prophase
d) metaphase
e) S phase
c) prophase
Which phase of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?
interphase
telophase
S phase
metaphase
anaphase
telophase
Following cytokinesis in an animal cell, how many centrioles does each new daughter cell possess?
a) zero
b) one
c) two
d) four
e) eight
two
One event occurring during prophase is __________.
a) the beginning of the formation of a spindle apparatus
b) cytokinesis
c) division of the centromere
d) the alignment of chromosomes in a single plane
e) the synthesis of a new nuclear envelope
a) the beginning of the formation of a spindle apparatus
In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?
a) the G1 phase
b) cytokinesis
c) prophase
d) metaphase
e) anaphase
b) cytokinesis
At which stage of mitosis are chromosomes lined up in one plane in preparation for their separation to opposite poles of the cell?
a) telophase
b) interphase
c) anaphase
d) prophase
e) metaphase
e) metaphase
Which best describes the kinetochore?
a) a structure composed of several proteins that associate with the centromere region of a chromosome and that can bind to spindle microtubules
b) the centromere region of a metaphase chromosome at which the D N A can bind with spindle proteins
c) the array of vesicles that will form between two dividing nuclei and give rise to the metaphase plate
d) the ring of actin microfilaments that will cause the appearance of the cleavage furrow
e) the core of proteins that forms the cell plate in a dividing plant cell
a) a structure composed of several proteins that associate with the centromere region of a chromosome and that can bind to spindle microtubules
If you were asked to label a model of a chromosome, the central portion (2) of a replicated chromosome would be labeled
a) kinetochore.
b) sister.
c) arm.
d) centromere.
e) Not enough information is provided to decide.
d) centromere.
If you saw a cell with condensed chromosomes lined up in the center of the cell, you would know that the cell was in
a) prophase.
b) prometaphase.
c) metaphase.
d) anaphase.
e) telophase
c) metaphase.
If you saw a cell with chromosomes condensing, you would know that the cell was in
a) prophase.
b) prometaphase.
c) metaphase.
d) anaphase.
e) telophase.
a) prophase.
If you saw a cell with chromosomes separating but not yet at the poles, you would know that the cell was in
a) prophase.
b) prometaphase.
c) metaphase.
d) anaphase.
e) telophase.
d) anaphase.
If you saw a cell reversing the changes to chromosomes seen in prophase, you would know that the cell was in
a) prophase.
b) prometaphase.
c) metaphase.
d) anaphase.
e) telophase.
e) telophase.
If the nuclear envelope has disappeared but the condensed chromosomes are not yet lined up, the cell is in
a) prophase.
b) prometaphase.
c) metaphase.
d) anaphase.
e) telophase.
b) prometaphase.
The law of independent assortment __________.
a) can account for a 9:3:3:1 ratio seen in the F2 generation
b) states that the alleles at different loci segregate independently from one another during a dihybrid cross
c) applies only to genes that are present on different chromosomes (or behave as if they were)
d) The first and second choices are correct.
e) The first, second, and third choices are correct
e) The first, second, and third choices are correct
Homologous pairs of chromosomes often __________.
a) contain different alleles
differ in length
b) carry different genes for different traits
c) are not both present in diploid somatic cells
d) are paired up in the G2 phase of the cell cycle
a) contain different alleles
If a heterozygous plant is allowed to self-pollinate, what proportion of the offspring will also be heterozygous?
1/4
1/3
1/2
2/3
all of them
1/2
A single genetic locus that controls more than one trait is said to be __________.
a) a quantitative character
b) polygenic
c) pleiotropic
d) epistatic
e)somatic
c) pleiotropic
If a plant variety is true-breeding for a dominant trait, then __________.
a) if the plant were allowed to self-pollinate, the dominant and recessive traits would consistently appear in a 3:1 ratio among the progeny
b) the plant is heterozygous for the trait
c) if the plant were crossed with a heterozygote, one-half of the progeny would show the dominant trait, and one-half would show the recessive trait
d) if the plant were allowed to self-pollinate over many generations, all of the progeny would have the dominant trait
e) the variety is unable to mutate
d) if the plant were allowed to self-pollinate over many generations, all of the progeny would have the dominant trait
How many genes are present in the human genome?
23
46
hundreds
tens of thousands
a virtually infinite number
tens of thousands
A karyotype is __________.
a) a method of identifying crossover events
b) all the possible gametes a person could produce
c) a list of all the genes a person carries
d) a display of all of an individual’s chromosomes arranged in pairs
e) the physical traits a person has
d) a display of all of an individual’s chromosomes arranged in pairs
Fertilization produces __________.
a) a diploid zygote
b) a haploid zygote
c) a multicellular haploid organism in a life cycle with an alternation of generations
d) a diploid zygote, except during the gametophyte stage of alternation of generations
e) a haploid zygote in some life cycles and a diploid zygote in others
a) a diploid zygote
In a diploid cell containing 10 chromosomes, meiosis results in the formation of daughter cells containing __________ chromosomes.
0
5
10
20
5
How many pairs of autosomes do humans have?
23
22
2
12
22
Humans have 46 chromosomes. This number of chromosomes will be found in __________.
a) all the egg and sperm cells
b) liver cells
c) all the cells of the body
d) all gamete-producing cells after meiosis I
e) all cells in anaphase of mitosis
b) liver cells
Which of the following is a function of mitosis in humans?
a) increasing genetic variability
b) decreasing the number of chromosomes
c) multiplication of body cells that are genetically identical to the parent cells d) production of sperm
e) production of eggs
c) multiplication of body cells that are genetically identical to the parent cells
Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________.
one … haploid
two … diploid
three … triploid
two … haploid
one … diploid
two … diploid
Which of the following results in cells that contain half the parental chromosome number?
a) mitosis
b) cytokinesis
c) interphase
d) meiosis
e) metaphase
d) meiosis
Synapsis occurs during __________.
a) anaphase I
b) prophase II
c) metaphase I
d) cytokinesis
e) prophase I
e) prophase I
Which of the following occurs during anaphase I?
A) Homologs separate and migrate toward opposite poles, guided by the spindle apparatus.
b) The cell is haploid.
c) Sister chromatids separate and migrate toward opposite poles.
d) Chromosomes line up in one plane.
e) Nuclei re-form
A) Homologs separate and migrate toward opposite poles, guided by the spindle apparatus.
What is the function of meiosis?
a) to make one cell with twice the number of chromosomes as the parent pairs
b) to make four cells with the same chromosome number as the parent
c) to make exact copies of the parent cell
d) to make cells with a haploid (half that of the parents) number of chromosomes
e) to make diploid spores
d) to make cells with a haploid (half that of the parents) number of chromosomes
Crossing over occurs during __________.
a) prophase II
b) metaphase II
c) metaphase I
d) cytokinesis
e) prophase I
e) prophase I
In a male mammal, every cell that undergoes meiosis gives rise to __________ sperm.
a) one
b) two
c) four
d) no set number
e) zero
four
Which of the following contributes to genetic variation in sexually reproducing species?
a) independent assortment, spindle formation, random fertilization
b) crossing over, internal fertilization, independent assortment
c) random fertilization, independent assortment, crossing over
d) internal fertilization, spindle formation, crossing over
e) random fertilization, DNA synthesis, independent assortment
c) random fertilization, independent assortment, crossing over
The major contribution of sex to evolution is that __________.
a) it is the only mechanism for species to reproduce
b) it increases genetic variation
c) it provides a way in which somatic mutations can be inherited
d) The first and second listed responses are correct.
e) The second and third listed responses are correct.
d) The first and second listed responses are correct.
Which of the following statements reflects an advantage that sexual reproduction likely provides over asexual reproduction?
a) In terms of energetic costs, sexual reproduction is a cheaper strategy than asexual reproduction for generating genetic variation in a population.
b) Although both reproductive strategies perpetuate the same combination of alleles within individuals in a population, sexual reproduction is energetically less costly than asexual reproduction.
c) Sexual reproduction maintains the same combination of alleles and does not run the risk of losing successful combination of alleles as is observed to occur in asexually reproducing organisms.
d) Although energetically more costly than asexual reproduction, sexual reproduction leads to different combinations of alleles that could provide adaptability in a changing environment.
e) Although sexual and asexual reproduction both offer opportunities for increasing genetic variation, sexual reproduction is comparatively lower in its energetic costs to the organism.
d) Although energetically more costly than asexual reproduction, sexual reproduction leads to different combinations of alleles that could provide adaptability in a changing environment.
Which of the following are ways in which gametes from one individual diploid cell can be different from one another?
a) mutation
b) crossing over
c) independent assortment
d) All of the listed choices are correct
e) None of the listed choices are correct
d) All of the listed choices are correct
Which of the following is not involved in the transmission of genes from parent organism to child?
a) DNA
b) gametes
c) somatic cells
d) mitosis
e) nucleotides
c) somatic cells
What allows sister chromatids to separate in which phase of meiosis?
a) release of cohesin along sister chromatid arms in anaphase I
b) crossing over of chromatids in prophase I
c) release of cohesin at centromeres in anaphase I
d) release of cohesin at centromeres in anaphase II
e) crossing over of homologs in prophase I
d) release of cohesin at centromeres in anaphase II
What is the main advantage of sexual reproduction over asexual reproduction?
a) It is more efficient at producing offspring.
b) Two parents can invest resources in offspring.
c) It allows for more competition.
d) It increases genetic variation among offspring.
e) None of the listed choices are correct
d) It increases genetic variation among offspring.
If you wished to observe chiasmata forming during meiosis, what stage of meiosis would have the best cells to use?
a) prophase I
b) anaphase I
c) prophase II
d) anaphase II
e) telophase II
a) prophase I
Physically, what are different alleles?
a) Different alleles are different particles found in gametes.
b) Different alleles are different DNA sequences found at the same locus on homologous chromosomes.
c) Different alleles are different DNA sequences found at the same locus on sister chromatids.
d) Different alleles are different phenotypes for a particular character.
e) None of the listed choices are correct.
b) Different alleles are different DNA sequences found at the same locus on homologous chromosomes.
