Chapter 8 Flashcards
Prokaryotic cells can divide through:
a. binary fission.
b. mitosis.
c. meiosis.
d. both mitosis and binary fission.
e. both mitosis and meiosis.
binary fission.
When tumors metastasize, cancer cells separate from the tumor and enter the _____ and _____ systems to spread to different parts of the body.
a. neurological; lymphatic
b. circulatory; lymphatic
c. circulatory; respiratory
d. digestive; circulatory
e. respiratory; neurological
circulatory; lymphatic
Sister chromatids are held together:
a. at the spindle fibers.
b. by complementary base pairing.
c. by the nuclear membrane.
d. at the centromere.
e. at their chiasmata.
at the centromere.
A(n) _____ is an analysis that reveals the number, shapes, and sizes of chromosomes in an individual cell.
a. amniocentesis
b. phenotype
c. genotype
d. chorionic villus sampling
e. karyotype
karyotype
The division of the cytoplasm during cell division is referred to as _____.
a. mitosis
b. synthesis
c. cytokinesis
d. interphase
e. cell-cycle control
cytokinesis
Which statement best describes telophase in mitosis?
a. DNA replication occurs.
b. Sister chromatids line up in the center of the cell.
c. Sister chromatids condense and spindle fibers form.
d. Spindle fibers begin to separate sister chromatids.
e. The nuclear membrane begins to form and cytokinesis occurs.
The nuclear membrane begins to form and cytokinesis occurs.
In which of the following ways can sex determination occur in humans?
a. by an XY chromosome carried by a sperm cell
b. by a Y chromosome within an egg cell
c. by an XY chromosome carried by an egg cell
d. by either an X or a Y chromosome carried by a sperm cell
e. by an X chromosome within an egg cel
by either an X or a Y chromosome carried by a sperm cell
What condition cannot be diagnosed using a karyotype?
a. Down syndrome
b. Trisomy 13
c. Turner syndrome
d. Sickle cell disease
e. Klinefelter syndrome
Sickle cell disease
The phase immediately following Gap 1 in the eukaryotic cell cycle is:
a. cytokinesis.
b. DNA synthesis.
c. mitosis.
d. Gap 2.
e. meiosis.
DNA synthesis.
During the process of _____ reproductive cells merge and create a new individual with the proper human genome of 46 chromosomes.
a. fission
b. meiosis
c. mitosis
d. recombination
e. fertilization
fertilization
The linear strands of DNA in eukaryotes are efficiently packed within the nucleus of the cell. The packing of DNA strands is mediated by proteins called _____.
a. histones
b. chromatins
c. telomeres
d. chromosomes
e. enzymes
histones
Contact inhibition describes the tendency of healthy cells to:
a. keep dividing until they bump into other cells or tissues.
b. break away from the tissue and spread to the circulatory system.
c. keep dividing until their telomeres become too short to continue.
d. spontaneously die in response to severe damage or other signaling.
e. ignore the spindle assembly checkpoint even if spindle fibers have not attached properly.
keep dividing until they bump into other cells or tissues.
Sister chromatids are held together:
a. at the centromere.
b. by the nuclear membrane.
c. by complementary base pairing.
d. at the spindle fibers.
e. at their chiasmata.
at the centromere.
Which method can be used to diagnose chromosomal abnormalities before birth?
a. karyotype
b. x-ray
c. ultrasound
d. gel electrophoresis
e. blood testing
karyotype
The section of noncoding, repetitive DNA that forms a protective cap on linear chromosomes is called a(n) _____.
a. chromatin
b. telomere
c. intron
d. exon
e. histone
telomere
Programmed cell death, or _____, takes place particularly in parts of the body where the cells are likely to accumulate significant genetic damage over time and are therefore at high risk of becoming cancerous.
a. necrosis
b. meiosis
c. mitosis
d. condensation
e. apoptosis
apoptosis
In some species, sex is determined by environmental, rather than genetic, factors. This is true of:
a. kangaroos.
b. humans.
c. bees.
d. turtles.
e. birds.
turtles.
Which term describes the unequal division of chromosomes during anaphase in meiosis I?
a. cytokinesis
b. metastasis
c. haploidy
d. contact inhibition
e. nondisjunction
nondisjunction
Which statement best describes metaphase in mitosis?
a. Sister chromatids line up in the center of the cell.
b. Sister chromatids condense and spindle fibers form.
c. DNA replication occurs.
d. Spindle fibers begin to separate sister chromatids.
e. The nuclear membrane begins to form and cytokinesis occur
Sister chromatids line up in the center of the cell.
Which statement best describes anaphase in mitosis?
a. Sister chromatids line up in the center of the cell.
b. DNA replication occurs.
c. Spindle fibers begin to separate sister chromatids.
d. The nuclear membrane begins to form and cytokinesis occurs.
e. Sister chromatids condense and spindle fibers form.
Spindle fibers begin to separate sister chromatids.
During replication, double-stranded DNA is unwound and separated by _____.
a. lipase
b. chromatin
c. DNA polymerase
d. histones
e. DNA helicase
DNA helicase
Hermaphrodites are organisms such as earthworms and garden snails that produce both male and female _____.
a. offspring
b. behaviors
c. chromosomes
d. hormones
e. gametes
gametes
In multicellular organisms, cells that undergo mitotic division but not meiotic division are called _____ cells.
a. reproductive
b. homologous
c. somatic
d. asexual
e. diploid
somatic
The chromosomes of most bacteria are:
a. linear.
b. capsular.
c. tetrahedral.
d. circular.
e. sickle-shaped.
circular.
During the _____ stage of the mitotic cell cycle, the chromosomes decondense back to strands of chromatin and each set of separated genetic material becomes enclosed in a nuclear envelope to form two daughter nuclei.
a. anaphase
b. telophase
c. Gap 1
d. S-phase
e. metaphase
telophase
For each of these types of organisms but one, every individual produces both male and female gametes. Which group is the exception?
a. most plants
b. earthworms
c. snails
d. hermaphrodites
e. birds
birds
Fetal cells can be collected by which of the following methods?
a. karyotyping
b. amniocentesis
c. swabbing the inside of the mother’s cheek
d. drawing blood from the mother
e. using an ultrasound
amniocentesis
Which disease involves having abnormally short telomeres?
a. cancer
b. Hutchinson-Gilford progeria syndrome
c. dwarfism
d. severe combined immunodeficiency disease (SCID)
e. Tay-Sachs disease
Hutchinson-Gilford progeria syndrome
Cancer cells differ from normal cells in two important aspects. They are:
a. the ability to metastasize and retention of contact inhibition.
b. apoptosis and contact inhibition.
c. loss of contact inhibition and the halting of all cell division.
d. a halting of all cell division and the ability to metastasize.
e. indefinite cell division and the loss of contact inhibition.
indefinite cell division and the loss of contact inhibition.
Nondisjunction:
a. is the division of cytoplasm into daughter cells.
b. is the cause of sex determination in birds and mammals.
c. can result in multiple copies of a chromosome but never zero copies of a chromosome.
d. is the unequal division of the genetic material during cell division.
e. occurs only in prophase I of meiosis
is the unequal division of the genetic material during cell division.
Which statement about sexual reproduction is true?
a. Sexual reproduction produces offspring that are genetically identical to the parents.
b. Sexual reproduction requires less energy than asexual reproduction.
c. Sexual reproduction always produces more offspring than asexual reproduction.
d. Sexual reproduction is less risky to the parents than asexual reproduction.
e. Sexual reproduction produces a greater variation in offspring than asexual reproduction.
Sexual reproduction produces a greater variation in offspring than asexual reproduction.
_____ marks the break in the cell cycle between the end of mitosis and the beginning of the synthesis stage.
a. Cytokinesis
b. DNA synthesis phase
c. Gap 2
d. Gap 1
e. Gap 3
Gap 1
Which statement best describes prophase in mitosis?
a. Spindle fibers begin to separate sister chromatids.
b. Sister chromatids condense and spindle fibers form.
c. The nuclear membrane begins to form and cytokinesis occurs.
d. Sister chromatids line up in the center of the cell.
e. DNA replication occurs.
Sister chromatids condense and spindle fibers form.
What type of chromosomal abnormality leads to the phenotype known as Down syndrome?
a. trisomy 22
b. trisomy 1
c. trisomy 21
d. monosomy 21
e. monosomy 22
trisomy 21
The human genome comprises:
a. 46 pairs of chromosomes.
b. 23 chromosomes.
c. an X and a Y chromosome.
d. 48 chromosomes.
e. 46 chromosomes.
46 chromosomes.
*Nondisjunction can occur at two different points. Either the homologues fail to separate during meiosis I or:
a. the homologues all go into the same gamete during meiosis II.
b. the sister chromatids fail to separate during meiosis I.
c. sister chromatids fail to separate during meiosis II.
d. the sister chromatids separate too soon in meiosis I.
e. the homologues fail to separate during meiosis II.
sister chromatids fail to separate during meiosis II.
What is a way that human female and male gametes differ?
a. Meiosis in females results in one large egg cell and several smaller polar bodies, whereas meiosis in males results in four evenly sized sperm cells.
b. Egg cells contain two copies of each chromosome, whereas sperm cells contain one copy.
c. Meiosis in females produces four egg cells, whereas meiosis in males produces one sperm cell and two or three polar bodies.
d. Egg cells are much smaller and have less cytoplasm than sperm cells.
e. All of a man’s sperm cells begin meiosis around the time he is born, whereas female meiosis begins at puberty.
Meiosis in females results in one large egg cell and several smaller polar bodies, whereas meiosis in males results in four evenly sized sperm cells.
Which condition is the result of too few sex chromosomes?
a. Down syndrome
b. Klinefelter syndrome
c. “super males”
d. Turner syndrome
e. “metafemales
Turner syndrome
Why does trisomy of chromosome 1 never show up in humans?
a. Nondisjunction of chromosome 1 results in the formation of a polar body.
b. The extra copy of chromosome 1 disintegrates early in fetal life so that normal development can occur.
c. Nondisjunction does not occur with larger chromosomes.
d. Trisomy 1 has so few symptoms that it is rarely detected.
e. Chromosome 1 has so many critical genes that a fertilized egg with an extra copy will die before implantation.
Chromosome 1 has so many critical genes that a fertilized egg with an extra copy will die before implantation.
Crossing over refers to:
a. incomplete dominance.
b. the process by which pieces of homologous chromosomes are exchanged.
c. independent assortment.
d. heterozygosity.
e. the peculiar line up of homologous chromosomes.
the process by which pieces of homologous chromosomes are exchanged.
Which statement about Turner syndrome is false?
a. People with Turner syndrome have only 45 chromosomes.
b. Turner syndrome is the only condition in which a human can survive without one pair of chromosomes.
c. People with Turner syndrome develop as females.
d. Turner syndrome may result in learning difficulties.
e. People with Turner syndrome are often taller than average.
People with Turner syndrome are often taller than average.
Turner syndrome is caused by _____ of the _____ chromosomes.
a. duplication; X
b. deletion; 21st
c. nondisjunction; sex
d. nondisjunction; 21st
e. deletion; sex
nondisjunction; sex
Which statement about individuals with Klinefelter syndrome is false?
a. People with Klinefelter syndrome are hermaphrodites.
b. The genotype of someone with Klinefelter syndrome is XXY.
c. People with Klinefelter syndrome have some female features.
d. Klinefelter syndrome usually leads to infertility.
e. People with Klinefelter syndrome develop as a male.
People with Klinefelter syndrome are hermaphrodites.
Which list includes ALL of the components of a DNA nucleotide?
a. a phosphate group, a five-carbon sugar, and a nitrogenous base
b. chromatids and histones
c. centromeres, telomeres, and nitrogenous bases
d. adenine, guanine, cytosine, and uracil
e. adenine, guanine, cytosine, and thymine
a phosphate group, a five-carbon sugar, and a nitrogenous base
Which cell type does not undergo mitosis?
a. stomach cells
b. skin cells
c. muscle cells
d. yeast
e. sperm cells.
sperm cells.
Which term describes the process by which cancer cells separate from a tumor and enter the circulatory system and lymphatic pathways?
a. nondisjunction
b. metastasis
c. contact inhibition
d. meiosis
e. metaphase
metastasis
Which process is necessary to prevent the doubling of genome size during sexual reproduction?
a. metastasis
b. mitosis
c. meiosis
d. contact inhibition
e. apoptosis
meiosis
After replication, the region of contact between sister chromatids, which occurs near the center of the two chromosome strands, is called the _____.
a. centriole
b. centromere
c. spindle fiber
d. chromatin
e. telomere
centromere
Binary fission is the only process by which _____ reproduce.
a. single-celled eukaryotes
b. somatic cells
c. prokaryotes
d. plant cells
e. gametes
prokaryotes
Sister chromatids line up at the center of the cell during which phase of mitosis?
a. metaphase
b. interphase
c. telophase
d. anaphase
e. prophase
metaphase
Chromosomes are replicated during which phase of the cell cycle?
a. the mitotic phase
b. Gap 1
c. G0
d. Gap 2
e. interphase
interphase
What is the correct order of events for the chromosomes during mitosis?
a. Chromosomes line up in the middle of the cell, cytokinesis occurs, sister chromatids separate, and chromosomes condense.
b. Cytokinesis occurs, chromosomes condense, chromosomes line up in the middle of the cell, and sister chromatids separate.
c. Chromosomes condense, sister chromatids separate, chromosomes line up in the middle of the cell, and cytokinesis occurs.
d. Sister chromatids separate, chromosomes condense, cytokinesis occurs, and chromosomes line up in the middle of the cell.
e. Chromosomes condense, chromosomes line up in the middle of the cell, sister chromatids separate, and cytokinesis occurs.
Chromosomes condense, chromosomes line up in the middle of the cell, sister chromatids separate, and cytokinesis occurs.
At what stage of meiosis can nondisjunction occur?
a. metaphase I
b. telophase I or telophase II
c. anaphase I
d. anaphase I or anaphase II
e. metaphase II
anaphase I or anaphase II
Put the events of the eukaryotic cell cycle in the correct, chronological order.
a. DNA synthesis, mitosis, cytokinesis, Gap 1, Gap 2
b. mitosis, Gap 1, Gap 2, cytokinesis, DNA synthesis
c. Gap 1, Gap 2, mitosis, DNA synthesis, cytokinesis
d. cytokinesis, mitosis, DNA synthesis, Gap 1, Gap 2
e. Gap 1, DNA synthesis, Gap 2, mitosis, cytokinesis
Gap 1, DNA synthesis, Gap 2, mitosis, cytokinesis
Individuals who inherit two X chromosomes and one Y chromosome develop as _____ with _____ syndrome.
a. females; Klinefelter
b. males; Turner
c. males; Klinefelter
d. males; Down
e. females; Turner
males; Klinefelter
Cells in the G0 phase do not:
a. grow or divide.
b. rest.
c. grow.
d. grow, divide, or rest.
e. divide.
grow or divide.
Human _____ cells are known to divide very rapidly when compared to _____ cells, which divide very slowly or not at all.
a. blood; muscle
b. neuronal; skin
c. muscle; blood
d. blood; skin
e. skin; blood
blood; muscle
Cytokinesis:
a. results in greater genetic diversity among daughter cells.
b. occurs during metaphase.
c. occurs during meiosis but not mitosis.
d. refers to the division of a cell’s cytoplasm.
e. occurs during mitosis but not meiosis.
refers to the division of a cell’s cytoplasm.
What happens when the telomeres of healthy cells become too short to protect the chromosome?
a. Additional cell divisions will damage the DNA and eventually cause cell death.
b. The organism will develop Hutchinson-Gilford progeria syndrome.
c. When telomeres become too short, cells rebuild their telomeres.
d. Cell division becomes unchecked and cancer develops.
e. The unprotected ends will fuse together.
Additional cell divisions will damage the DNA and eventually cause cell death.
Which event does NOT occur during prophase I of meiosis?
a. Crossing over occurs between homologous pairs of sister chromatids.
b. The nuclear membrane disintegrates.
c. Homologous pairs of chromosomes separate and move toward the poles.
d. Replicated chromosomes begin to condense.
e. The spindle is formed.
Homologous pairs of chromosomes separate and move toward the poles.
Match the chromosomal abnormality with its resulting phenotype.
a. trisomy 22; cystic fibrosis
b. trisomy 21; cystic fibrosis
c. trisomy 1; Klinefelter syndrome
d. trisomy 21; Down syndrome.
e. trisomy 22; Down syndrome
trisomy 21; Down syndrome.
During which phase of the cell cycle is DNA replicated?
a. prophase
b. metaphase
c. interphase
d. telophase
e. anaphase
interphase
During which phase of the mitotic cell cycle are two daughter nuclei formed?
a. metaphase
b. telophase
c. cytokinesis
d. anaphase
e. prophase
telophase
What is true about meiosis in men and women?
a. In egg production, the division of cells in meiosis produces cells of equal size.
b. Women make sperm, whereas men make eggs.
c. Sperm are larger in size than eggs.
d. The egg is motile, whereas the sperm is not.
e. Sperm production results in four cells from one starting cell; however, for eggs, only one egg results from one starting cell.
Sperm production results in four cells from one starting cell; however, for eggs, only one egg results from one starting cell.
A cell undergoes mitosis, resulting in two daughter cells with 36 chromosomes each. How many chromosomes did the parent cell normally have?
a. 72
b. 36
c. 24
d. 18
e. 9
36
In ants, bees, and wasps, sex determination for the male sex occurs when an offspring has which of the following conditions?
a. an XY sex chromosome genotype
b. a haploid genome
c. a diploid genome
d. Males are not a distinct sex; these species are hermaphroditic.
e. an XX sex chromosome genotype
a haploid genome
Amniocentesis can be performed in the third or fourth month of pregnancy for the purposes of:
a. testing the mother for anemia.
b. obtaining a karyotype of the fetus.
c. testing the fetus for anemia.
d. obtaining an image of fetal development.
e. analyzing the health of the placenta.
obtaining a karyotype of the fetus.
What type of environment might be conducive to producing offspring by asexual reproduction versus sexual reproduction if the option is available?
a. a habitat with predatory mating partners
b. a variable environment
c. an environment with a population that has a high rate of sexually transmitted diseases
d. a stable environment
e. an environment with a population that already has enough genetic diversity
a stable environment
Which is not a disadvantage of sexual reproduction?
a. It takes time and energy to find a mating partner.
b. Sexual reproduction breaks down genotypes that are well adapted for a stable environment.
c. Organisms can expose themselves to danger during the mating process.
d. The transfer of genetic information from generation to generation is not as efficient as it is during asexual reproduction.
e. Variability among offspring enables parents to produce a range of offspring, any one of which may be suited to potential changes in the environment.
Variability among offspring enables parents to produce a range of offspring, any one of which may be suited to potential changes in the environment.
Which statement about sex determination in humans is true?
a. One would expect babies to have two Y chromosomes about half the time.
b. The father’s sperm determines the gender of a baby.
c. An X chromosome is smaller than a Y chromosome.
d. In the absence of a Y chromosome, the fetal gonads develop into ovaries, not testes.
e. Without a Y chromosome, a fertilized egg usually dies.
The father’s sperm determines the gender of a baby.
What is the only condition in humans in which a person can survive without one of a pair of chromosomes?
a. trisomy 13
b. Turner syndrome
c. Down syndrome
d. Klinefelter syndrome
e. Metafemale condition
Turner syndrome
Part of the cytoskeleton of a cell, formed in prophase (in mitosis) or in prophase I (in meiosis), from which fibers extend that organize and separate the sister chromatids, is called the _____.
a. spindle
b. chromatin
c. centriole
d. histone
e. microtubule
spindle
What is the definition of “female”?
a. producing the smaller, less motile gamete
b. producing more gametes
c. producing the female reproductive system
d. producing the smaller, more motile gamete
e. producing the larger, less motile gamete
producing the larger, less motile gamete
*Which molecule is responsible for proofreading and repairing DNA during replication?
a. DNA helicase
b. DNA polymerase
c. chromatin
d. histones
e. lipase
DNA polymerase
How does crossing over introduce variation in meiosis?
a. It causes eggs and sperm to unite in different ways.
b. It causes all the homologous chromosomes to find new partners.
c. It causes homologous chromosomes to be grouped differently.
d. It increases the amount of DNA in the nucleus.
e. It positions alleles next to each other that previously were not together.
It positions alleles next to each other that previously were not together.
What maintains a stable genome size in a species?
a. DNA helicase
b. telomeres
c. meiosis
d. gametes
e. DNA polymerase
meiosis
*Which statement about homologous chromosomes is false?
a. One of the two homologous chromosomes is produced by the cell during the DNA replication.
b. Both chromosomes carry information about the same genetic characteristics.
c. Both chromosomes have centromeres in the same location.
d. Both chromosomes are the same length.
e. One homologue is of paternal origin, whereas the other is of maternal origin.
One of the two homologous chromosomes is produced by the cell during the DNA replication.
Which statement about crossing over is true?
a. New versions of genes arise through crossing over.
b. The combination of physically linked alleles on a chromosome is different after crossing over.
c. Different numbers of genes can be exchanged between homologous chromosomes during crossing over.
d. During crossing over, genetic material is exchanged between sister chromatids.
e. Genetic variation can increase substantially when crossing over occurs between nonhomologous chromosomes.
The combination of physically linked alleles on a chromosome is different after crossing over.
How many sex chromosomes does the normal human female inherit from her mother?
a. 1
b. 2
c. 23
d. 46
e. 2 pairs
1
What is the best definition of a homologous chromosome?
a. one of two identical chromosomes held together by a centromere
b. a chromosome that has undergone genetic recombination
c. one of two chromosomes of the same length and type inherited from a father or mother
d. the type of chromosome found in prokaryotes
e. the central area that joins two chromatids
one of two chromosomes of the same length and type inherited from a father or mother
In eukaryotes, _____ binds to and winds around _____ proteins, enabling efficient packing of DNA.
a. DNA; chromatin
b. chromatin; DNA
c. histone; chromatin
d. chromatin; histone
e. spindle fiber; centromere
chromatin; histone
Hermaphrodites are organisms such as earthworms and garden snails that produce both male and female _____.
a. offspring
b. behaviors
c. chromosomes
d. hormones
e. gametes
gametes
Which statement about DNA replication in eukaryotes is true?
a. Nucleotides are added to the 5’ end of the growing DNA strand.
b. DNA replication only occurs in somatic cells.
c. DNA helicase adds nucleotides with complementary bases to the strand of DNA that is being synthesized.
d. Errors that occur during DNA replication are repaired by DNA polymerase.
e. Nucleotides are added from beginning to end of one strand, from 5’ to 3’, and then to the other strand.
Errors that occur during DNA replication are repaired by DNA polymerase.
Choose the answer that best explains the specific functionality of the Y chromosome.
a. The Y chromosome contains genes for male sexual development and for other essential non-sex-related functions.
b. The Y chromosome initiates fetal male development and then changes into an X chromosome.
c. The Y chromosome has a large number of genes that direct the development of masculine features throughout a male’s lifetime.
d. The Y chromosome contains a small number of genes needed to set off a cascade of gene activity, instructing the fetal gonads to develop into testes, which then produce hormones that direct the rest of male development.
e. The Y chromosome initiates male gonad development and then disintegrates into a polar body.
The Y chromosome contains a small number of genes needed to set off a cascade of gene activity, instructing the fetal gonads to develop into testes, which then produce hormones that direct the rest of male development.
Telomeres have been directly linked to aging in humans. If scientists were able to develop treatments that could reverse the shortening of telomeres, would they be able to reverse the aging of humans?
a. No, organisms that have lost normal telomere function are sterile.
b. No, with the exception of the cells that produce sperm, most cells that can rebuild their telomeres are cancerous.
c. No, aging in humans has more to do with gene mutation than telomeres.
d. Yes, this is the subject of intense research.
e. Yes, scientists have succeeded in creating immortal rats through telomere treatments.
No, with the exception of the cells that produce sperm, most cells that can rebuild their telomeres are cancerous.
*Which cell type lacks telomeres?
a. bacterial cell
b. skin cell
c. plant cell
d. neuron
e. muscle cell
bacterial cell
If DNA replication occurs by unwinding and rebuilding, then:
a. the three resulting DNA molecules will contain two new strands and one original strand.
b. the three resulting DNA molecules will contain one new strand and two original strands.
c. the two resulting DNA molecules are completely composed of newly synthesized strands.
d. the two resulting DNA molecules each contain one original strand and one new strand.
e. the two resulting DNA molecules are an unpredictable mixture of old and newly synthesized DNA.
the two resulting DNA molecules each contain one original strand and one new strand.
Which statement about prokaryotic reproduction is true?
a. A single circular DNA helix is replicated into two identical circular DNA helices.
b. It is a form of sexual reproduction.
c. Mitosis is used.
d. The chromosomes wind up into tight packages before cellular division.
e. Four cells are produced from a single parent cell.
A single circular DNA helix is replicated into two identical circular DNA helices.
Which does not contribute to variability of the offspring in sexual reproduction?
a. replication of the chromosomes during interphase
b. crossing over in prophase I of meiosis
c. combining genes from two unrelated parents during fertilization
d. the swapping of genetic information between homologues during meiosis
e. the variety of ways homologues can separate in metaphase I
replication of the chromosomes during interphase
Which cell type must rebuild its telomeres?
a. red blood cells
b. somatic cells
c. muscle cells
d. reproductive cells
e. neurons
reproductive cells
The spindle begins to assemble at which phase of the mitotic cell cycle?
a. interphase
b. prophase
c. metaphase
d. anaphase
e. telophase
prophase
*What is not a known mechanism of sex determination?
a. Sex is determined by the temperature at which eggs are incubated.
b. Males develop from eggs with no chromosomes, whereas females develop from diploid eggs.
c. Females have two different chromosomes (WZ), whereas males have two of the same chromosome (ZZ).
d. An individual is both male and female at the same time, having gonads for each sex.
e. Females develop from diploid (fertilized) eggs, whereas males develop from haploid (unfertilized) eggs.
Males develop from eggs with no chromosomes, whereas females develop from diploid eggs.
*During DNA replication, each strand serves as a _____ for the new _____ strand.
a. blueprint; identical
b. proofreader; complementary
c. blueprint; template
d. proofreader; supplementary
e. template; complementary
template; complementary
Which statement is true?
a. Individuals with trisomy in chromosomes 1, 13, or 21 can live long lives.
b. The gametes of a male at age 80 will have as many errors as the gametes of a female half that age.
c. Some chromosomes are more likely than others to not separate during cell divisions, which is why trisomy 21 is more common than other trisomies.
d. Nondisjunction can occur when sister chromatids fail to separate during meiosis I or when homologues fail to separate during meiosis II.
e. The survival rate of developing embryos with trisomy is related to chromosome size.
The survival rate of developing embryos with trisomy is related to chromosome size.
*Before cytokinesis can occur, a cell must successfully pass which important checkpoint?
a. the G2/M checkpoint
b. the spindle assembly checkpoint
c. the G1/S checkpoint
d. the G1/G0 checkpoint
e. the DNA repair checkpoint
the spindle assembly checkpoint
What is the most likely reason that relatively few XXX individuals have been studied?
a. XXX individuals are sterile, and cannot pass their condition on to offspring.
b. XXX individuals generally exhibit no physical or cognitive abnormalities, and may live their entire lives unaware of their condition.
c. Due to the importance of the X chromosome, very few XXX fetuses survive to term.
d. XXX individuals only occur at about a rate of 1 in 100,000 women.
e. The XXX condition is impossible to observe in humans.
XXX individuals generally exhibit no physical or cognitive abnormalities, and may live their entire lives unaware of their condition.
*The rate at which mitosis occurs varies dramatically for different types of cells. The most rapid cell division occurs:
a. in the gametes.
b. on the skin.
c. in the liver and the brain.
d. in the blood and the cells lining the various tissues of organs.
e. in the blood and the heart.
in the blood and the cells lining the various tissues of organs.
A diploid organism is produced from haploid cells through the process of:
a. fertilization.
b. meiosis.
c. DNA synthesis.
d. mitosis.
e. cytokinesis.
fertilization.
Which arrangement of sex chromosomes is least likely to develop into a viable fetus?
a. X_
b. XXX
c. XXY
d. _Y
e. XYY
_Y
*The _____ is a disk-like group of proteins to which the spindle fibers attach during metaphase of mitosis.
a. centromere
b. nuclear envelope
c. microtubule
d. metaphase plate
e. kinetochore
kinetochore
If a cell containing 10 chromosomes divides by mitosis, how many daughter cells will be produced?
a. 10
b. 20
c. 2
d. 15
e. 5
2
Which arrangement of sex chromosomes can result only from nondisjunction in the father’s gametes?
a. YYY
b. XXX
c. XYY
d. XXY
e. X_
XYY
Healthy individuals may have just one sex chromosome, as long as it is an X chromosome. Why can’t a person survive with a Y chromosome and no X chromosome?
a. The Y chromosome has a full complement of genetic material, much of which is vital to life; the X chromosome is missing the vast majority of these genes.
b. A person with just an X chromosome would be a female, whereas a person with just a Y chromosome would not have a sexual identity.
c. The X chromosome has a full complement of genetic material, much of which is vital to life; the Y chromosome does not carry individually vital genes.
d. The X chromosome is capable of duplicating itself, meaning an affected individual will eventually have two X chromosomes; however, the Y chromosome is incapable of duplicating itself.
e. It actually is possible to survive with just a Y chromosome; it’s just very rare.
The X chromosome has a full complement of genetic material, much of which is vital to life; the Y chromosome does not carry individually vital genes.
What is one reason why genetic disorders involving trisomy are more common in babies born to older mothers?
a. Aging egg cells can develop problems that interfere with normal cell division.
b. Spindle fibers increase in size as egg cells age.
c. Older egg cells can only be fertilized by older sperm cells, which are prone to nondisjunction.
d. Older egg cells allow for fertilization by more than one sperm as often as a single sperm, resulting in trisomy.
e. There is increased cohesion between sister chromatids in older cells.
Aging egg cells can develop problems that interfere with normal cell division.
Which statement about sex determination in humans is true?
a. Each normal egg cell has one X chromosome.
b. Egg cells can receive either an X or a Y chromosome during meiosis due to independent assortment.
c. Males are produced when a sperm carrying a Y chromosome fertilizes an egg carrying a Y chromosome.
d. Sperm transfer either XX or XY chromosomes to the egg cell during fertilization.
e. Females are produced when a sperm carrying an X chromosome fertilizes a polar body.
Each normal egg cell has one X chromosome.
Which statement about the human karyotype is false?
a. It can reveal whether the fetus has an abnormal number of chromosomes.
b. It can be made from cells gathered by amniocentesis.
c. It reveals the gender of the individual.
d. It can be made from placental tissue.
e. It can be used to diagnose genetic diseases like cystic fibrosis.
It can be used to diagnose genetic diseases like cystic fibrosis.
*What defects in egg cells lead to increased rates of nondisjunction as females age?
a. increased viscosity of cytoplasm
b. breakdown in the nuclear envelope
c. increased rates of crossing over
d. reduction in the stability of spindle fibers
e. degradation of chromosome 21
reduction in the stability of spindle fibers
What is the direct product of DNA replication?
a. the lining up of chromosomes in mitosis metaphase
b. cytokinesis
c. two sister chromatids
d. the two strands in a DNA helix
e. the production of two spindle fibers
two sister chromatids
The float in a toilet tank stops the filling of the tank when the water reaches a certain level. If the float is damaged so that it sinks instead, the water will overflow the tank after each flush. This scenario is similar to which of the following cellular concepts?
a. loss of contact inhibition
b. failure of cancer cells to metastasize
c. increase in cell suicides
d. loss of the ability to perform mitosis
e. the lengthening of telomeres
loss of contact inhibition
Joseph went to a copy center and used a copy machine to make a duplicate set of 46 pages. He then stapled every copied sheet to its original. This is similar to how a cell replicates its chromosomes in mitosis. Why would a cell do something similar during mitosis?
a. to introduce helpful mutations that make mitosis more successful
b. to keep the cell from dividing too early
c. to keep the copies and originals organized for later separation
d. to keep the cell from making too many copies of a particular chromosome
e. to allow the cell to move onward into the Gap 1 phase
to keep the copies and originals organized for later separation
What cells types remain in G0 phase for years at a time?
a. neurons
b. reproductive cells
c. skin cells
d. blood cells
e. cells lining the intestinal wall
neurons
