a) trisomy 22
b) trisomy 21
c) monosomy 21
d) monosomy 22
e)Either the first or third answer choices could lead to Down syndrome.
a) during mitosis and meiosis because the condensed chromosomes are thicker and therefore more prominent.
b) during asexual reproduction.
c) in the mitochondria because they are circular.
d) during interphase when they are concentrated in the nucleus.
e) during interphase because they are uncoiled and have a more linear structure.
a) Four cells are produced from a single parent cell.
b) Mitosis is used.
c) A single circular DNA helix is replicated into two identical circular DNA helices.
d) It is a form of sexual reproduction.
e) The chromosomes wind up into tight packages before cellular division.
a) the two resulting DNA molecules are an unpredictable mixture of old and newly synthesized DNA.
b) the two resulting DNA molecules each contain one original strand and one new strand.
c) the two resulting DNA molecules are completely composed of newly synthesized strands.
d) both A and B are true.
e) None of the above is true about DNA replication.
a) telomere; a cell after 50 cell divisions
b) circular chromosome; linear chromosome
c) binary fission; mitosis
d) asexual reproduction; sexual reproduction
e) DNA replication; cell division
b) daughter cells with twice as much genetic material and a unique collection of alleles.
c) daughter cells with the same number and composition of chromosomes.
d) daughter cells with the same number of chromosomes but different combinations of alleles.
e) eight daughter cells.
a) It takes time and energy to find a mating partner.
b) The transfer of genetic information from generation to generation is not as efficient as it is during asexual reproduction.
c) Organisms can expose themselves to danger during the mating process.
d) Variability among offspring enables parents to produce a range of offspring, any one of which may be suitable to changes in the environment.
e) Sexual reproduction breaks down genotypes that are well-adapted for a stable environment.
a) Down syndrome
c) Turner syndrome
d) Klinefelter syndrome
e) “Super Males”
a) Gap 1
c) DNA Synthesis phase
d) Gap 2
e) None of the above.
a) Males are more brightly colored.
b) Males are more aggressive.
c) Males produce motile gametes.
d) Males are larger.
e) All of the above are correct.
a) asexual reproduction; sexual reproduction
b) DNA replication; cell division
c) circular chromosome; linear chromosome
d) telomere; a cell after 50 cell divisions
e) binary fission; mitosis
a) Sperm production results in four cells from one starting cell; for eggs, only one egg results from one starting cell.
b) The egg is motile, while the sperm is not.
c) Sperm are larger in size than eggs.
d) Women make sperm, while men make eggs.
e) In egg production, the division of cells in meiosis produces cells of equal size.
a) much longer than it is.
b) attached to a large number of stick proteins.
c) found in a greater number of chromosomes.
d) much more tightly coiled.
e) circular, as it is in prokaryotes.
a) dividing into two; genetically different offspring
b) dividing into four; genetically different offspring
c) mitosis; meiosis
d) dividing into two; genetically identical offspring
e) meiosis; mitosis
a) two identical daughter cells are produced.
b) chromosomes line up in the center of the cell during metaphase.
c) genetic variation among the daughter cells is increased.
d) diploid cell occurs in the second division of meiosis, but in the first division of mitosis.
e) haploid gametes are produced that are all identical in their allelic composition.
a) The central area that joins two chromatids
b) One of two identical chromosomes held together by a centromere
c) One of two chromosomes of the same length and type inherited from a father or mother
d) A chromosome that has undergone crossing over
e) The type of chromosome found in prokaryotes
a) Crossing over between tetrads occurs.
b) Spindle is formed.
c) Homologous pairs of chromosomes separate and move toward the poles.
d) A protein structure called a synaptonemal complex forms between the homologues.
e) Chromosomes begin to condense.
a) Variability among offspring enables parents to produce a range of offspring, any one of which may be suitable to changes in the environment.
b) Sexual reproduction breaks down genotypes that are well-adapted for a stable environment.
c) The transfer of genetic information from generation to generation is not as efficient as it is during asexual reproduction.
d) It takes time and energy to find a mating partner.
e) Organisms can expose themselves to danger during the mating process.
a) omeres in the same location.
b) One homologue is of paternal origin, while the other is of maternal origin.
c) Both chromosomes are the same length.
d) One of the two homologous chromosomes is produced by the cell during DNA synthesis phase.
e) Both chromosomes carry information about the same genetic characteristics.
a) It positions alleles next to each other that previously were not together.
b) It causes all the homologous chromosomes to find new partners.
c) It increases the amount of DNA in the nucleus.
d) It causes homologous chromosomes to be grouped differently.
e) It causes eggs and sperm to unite in different ways.
a) Interphase (Gap-1), Prophase, Telophase, Cytokenesis, S phase, Gap-2, Metaphase, Anaphase
b) Interphase (Gap-1), S phase, Gap-2, Metaphase, Prophase, Telophase, Anaphase, Cytokenesis
c) Interphase (Gap-1), Cytokenesis, S phase, Gap-2, Metaphase, Prophase, Telophase, Anaphase
d) Interphase (Gap-1), Prophase, Metaphase, Anaphase, Telophase, Cytokenesis, S phase, Gap-2
e) Interphase (Gap-1), S phase, Gap-2, Prophase, Metaphase, Anaphase, Telophase, Cytokenesis
a) Both chemotherapy and radiation therapy work by disrupting cell division.
b) Radiation therapy has a significantly higher success rate than does chemotherapy.
c) The drugs used in chemotherapy circulate throughout the entire body, while radiation therapy directs high energy radiation only at the part of the body where the tumor is located.
d) In radiation therapy, the nearby tissue may be harmed, while in chemotherapy, the rate at which healthy cells divide may be reduced.
e) Both chemotherapy and radiation therapy have side-effects.
a) segregation only.
b) replication only.
c) mitosis only.
d) meiosis only.
e) both mitosis and meiosis.
a) Gap, Synthesis, and Condensing.
b) Gap 1, Synthesis 1 and Synthesis 2
c) Gap 1, DNA Synthesis, and Gap 2.
d) Gap 1, Gap 2, and Gap 3.
e) Synthesis 1, Synthesis 2, and Synthesis 3
a) A man who inherits two or three Y chromosomes as a result of an error in meiosis is fully normal.
b) Women don’t have a Y chromosome and are not genetically disadvantaged.
c) Sperm contribute no genetic information to the egg in fertilization.
d) Eggs that are not fertilized can still develop into normal human beings.
e) Males are not needed in sexually reproducing species.
a) can be used to diagnose Down syndrome in humans.
b) reveals the autosomes but not the sex chromosomes.
c) can be used to determine the sex of a fetus in humans.
d) can be produced only from cells in telophase of mitosis.
e) Both a) and c) are correct.
a) somatic cells.
b) somosis cells.
c) interphase cells.
d) germ cells.
e) skin cells.
a) a halting of all cell division and the ability to metastasize.
b) the ability to metastasize and contact inhibition.
c) apoptosis and contact inhibition.
d) loss of contact inhibition and the halting of all cell division.
e) indefinite cell division and the loss of contact inhibition.
a) Gap-1, S-phase and Gap-2
b) Gap-1 and Gap-2
c) prophase and metaphase
d) Gap 1, Gap-2 and prophase
e) S-phase and prophase
a) two haploid cells
c) two daughter cells
d) spindle fibers
e) nuclear membranes
a) unwinds to allow tetrads to form.
b) binds to the metaphase plate, enabling chromosome division.
c) is the final DNA structure after replication.
d) condenses, becoming more tightly coiled.
e) unwinds to allow synapsis between homologous pairs of chromatids.
e) X_ (also written as XO)
a) Asexual reproduction, because there are more bacteria than plants and animals.
b) Asexual reproduction, because binary fission is more efficient.
c) Sexual reproduction, insures more offspring.
d) Sexual reproduction, because there are more plants and animals than bacteria.
e) Neither method is better—each is effective in different environments for different kinds of organisms
b) sex determination.
e) crossing over.
a) is the unequal division of the genetic material during cell division.
b) occurs only in prophase I of meiosis.
c) is the cause of sex determination in birds and mammals.
d) is the division of cytoplasmic constituents.
e) occurs during mitosis but not meiosis.
a) results in greater genetic diversity among daughter cells.
b) occurs during mitosis but not meiosis.
c) refers to the division of a cell’s cytoplasm.
d) occurs during metaphase.
e) All of the above are true.
a) dormant phase.
c) static phase.
d) S phase.
a) In the absence of a Y chromosome, the fetal gonads develop into testes, not ovaries.
b) An X chromosome is smaller than a Y chromosome.
c) Without a Y chromosome, a fertilized egg usually dies.
d) The father’s sperm determines the gender of a baby.
e) One would expect babies to have two Y chromosomes about half the time.
a) It can be made from placental tissue.
b) It reveals the gender of the individual.
c) It can be made from cells gathered by amniocentesis.
d) It can reveal whether non-disjunction occurred in an egg or sperm.
e) It can be used to diagnose genetic diseases like cystic fibrosis.
a) blueprint; template
b) master model; transcribed
c) template; complementary
d) template; supplementary
e) proofreader; complementary
c) four times as much
d) twice as much
e) the same amount
b) DNA Synthesis
d) Gap 1
e) Gap 2
a) kidney cells.
b) brain cells.
c) sperm cells.
d) All of the above are correct.
e) Both a) and b) are correct.
a) DNA replication in most cells stops when the double helix comes in contact with particular enzymes.
b) Genes in the DNA are inhibited from expressing themselves.
c) most cells don’t begin to divide until they bump up against other cells or collections of cells.
d) most cells stop dividing when they have reached 50 cell divisions.
e) most cells stop dividing when they bump up against other cells or collections of cells.
a) the chromatids begin to separate from the metaphase plate.
b) the sister chromatids from the homologous pairs of chromosomes come together as a tetrad.
c) crossing over begins.
d) the nuclear envelope re-forms.
e) the chromatin coils into thicker, visible chromatids.
a) nondisjunction (chromosomes don’t separate).
b) prophase I (replicated chromosomes condense).
c) metaphase I (paired homologs align down equator).
d) anaphase II (centromeres part).
e) crossing-over (swapping genetic material between chromosome homologs).
a) A woman with three X chromosomes produces oocytes with two X chromosomes, which could result in her giving birth to a XXY son.
b) This condition does not exist because a fetus with three X chromosomes cannot survive birth.
c) Women with this condition are usually marked by profound mental impairment.
d) Women with this disease are able to give birth to normal children with the normal number of sex chromosomes.
e) Both a) and d) are likely to be correct.
a) have a mixtures of maternal and paternal chromosomes.
b) are created during meiosis.
c) usually result in aborted fetuses.
d) contain more dominant genes than recessive.
e) Both a) and b) are correct.
a) are haploid.
b) each have two chromosomes.
c) each have a different number of chromosomes than the original cell.
d) are genetically identical to each other and to the original parent.
e) are genetically unique to each other and to the original parent.
c) M phase.
a) the mitotic phase
b) the Gap 2 phase
c) the Gap 1 phase
d) the replication phase
e) the DNA synthesis phase
a) is opposite to that of humans, in that the mother has one copy of each of two different sex chromosomes.
b) is similar to that of humans, in which the father has one copy of each of two different sex chromosomes.
c) is based on the males being diploid and the females being haploid.
d) is based on the males being haploid and the females being diploid.
e) is based on temperature.
a) interphase ; prophase ; anaphase ; metaphase ; telophase ; cytokinesis
b) interphase ; prophase I ; metaphase I; anaphase I; telophase I; cytokinesis ; prophase II ; metaphase II; anaphase II; telophase II; cytokinesis
c) interphase ; mitosis ; meiosis ; cytokinesis
d) interphase ; prophase ; metaphase ; anaphase ; telophase ; cytokinesis
e) interphase ; prophase I ; metaphase I; anaphase I; telophase I; prophase II ; metaphase II; anaphase II; telophase II; cytokinesis
b) nuclear membranes
c) two daughter cells
d) spindle fibers
e) two haploid cells
a) Gap-2 (G2)
b) Gap-1 (G1)
e) Synthesis (S phase)
a) Drugs that interfere with cell division are administered to the patient.
b) Chemotherapy drugs circulate throughout the entire body.
c) Chemotherapy drugs disrupt normal systems that rely on the rapid and constant production of new cells.
d) All of the above are correct.
e) Only a) and b) are correct.
a) the result of crossing over.
c) identical molecules of DNA resulting from replication.
d) homologous chromosomes.
e) produced in meiosis but not in mitosis.
a) the chromatin condenses into chromosomes.
b) separation of the chromatids begins.
c) the centromeres have arrived at the equatorial plate.
d) the nuclear envelope disappears.
e) None of the above answers is correct.
a) translocation of genetic material on chromosome 21
b) all or part of a third copy of chromosome 21
c) a truncated copy of chromosome 3
d) the absence of a second copy of chromosome 10
e) two Y chromosomes
a) a brother and a sister producing children together
b) combining genes from two unrelated parents during fertilization
c) the different ways homologous can separate in Metaphase I
d) crossing over in Prophase I of meiosis
e) the swapping of genetic information between homologues during meiosis
a) skin cells.
c) stomach cells.
d) sperm cells.
e) muscle cells.
a) DNA polymerases.
e) barr bodies.
b) the lining up of chromosomes in mitosis metaphase
c) two sister chromatids
d) the two strands in a DNA helix
e) the production of two spindle fibers
a) one of two identical chromosomes held together by a centromere
b) the central area that joins two chromatids
c) the type of chromosome found in prokaryotes
d) one of two chromosomes of the same length and type inherited from a father or mother
e) a chromosome that has undergone crossing over
a) consists of a single linear strand of double-stranded DNA.
b) consists of two linear strands of double-stranded DNA.
c) condenses only during metaphase of mitosis.
d) is usually circular.
e) Both a) and b) can be correct, depending on whether replication has occurred.
c) contact inhibition
a) Gap 3.
c) Gap 2.
d) Gap 1.
e) None of the above is correct; there is no stage between the replication and division stages in the cell cycle.
Which is a likely explanation for why there are no data included on the graph for maternal ages above 45?
a) In women over 45, the incidence of Down syndrome is confounded by other genetic disorders.
b) Because women of younger ages are more open to giving data than older women.
c) Because the number of births to women older than 45 is much smaller than births to younger women.
d) Above 45, the incidence of Down syndrome approaches 100%.
e) Women over the age of 45 are not able to give birth.
a) Development and differentiation are really two words for the same thing.
b) Development involves meiosis; differentiation involves the creation of the three germ layers.
c) Development involves mitosis and embryonic growth; differentiation involves specialization of tissues.
d) Development involves the events just before birth; differentiation specifically refers to neurulation.
e) Development involves the formation of three germ layers; differentiation includes the formation of a blastula.
a) Separating the father’s sperm according to weight, as the X chromosome weighs more than the Y chromosome.
b) Separating the father’s sperm according to weight, as the Y chromosome weighs more than the X chromosome.
c) Semen with more Y sperm tends to be more acidic and can be tested for.
d) Add a fluorescent dye to the father’s sperm—sperm that show more fluorescence contain an X chromosome.
e) Both a) and d) are correct.
a) Metaphase is the only stage of the cell cycle in which both sets of homologous chromosomes are present in the cell.
b) Metaphase is the only stage of the cell cycle in which the cell membrane is permeable to dye.
c) Metaphase is the only stage of the cell cycle in which single chromosomes move toward the poles.
d) Metaphase is the only stage of the cell cycle in which the chromosomes have condensed and aligned, but have not yet separated.
e) Metaphase is the only stage of the cell cycle in which both sister chromatids of each chromosome are present in the cell.
a) cytoplasm is divided
b) centromeres separate
c) sister chromatids pair up and join at the centromere
d) two daughter nuclei are formed
e) chromosomes line up in single file
a) cancer cells rebuild their centromeres after every cell division.
b) cancer cells avoid interphase during cell division.
c) cancer cells break down their telomeres after every cell division.
d) cancer cells break down their centromeres after every cell division.
e) cancer cells rebuild their telomeres after every cell division.
a) anaphase I of meiosis.
b) prophase I of mitosis.
c) prophase I of mitosis and meiosis.
d) prophase I of meiosis.
e) None of the above is correct.
c) The traits will show up equally in males and females.
d) The gender that’s incubated at a higher temperature.
e) Males and females are equally likely to display a sex-linked recessive trait.
a) New genes can enter the population and be acted upon by evolution.
b) It is a way to get rid of old defective genes.
c) The DNA replication process becomes more fine-tuned the more errors it makes.
d) Most errors are, in fact, good for the organism in which they occur.
e) Errors in DNA replication can never be a good thing.
a) females with an XXX genotype.
b) females with an XX genotype.
c) females with an XXY genotype.
d) females with an XY genotype.
e) males with an XX genotype.
a) is similar to that of humans, in which the father has one copy of each of two different sex chromosomes.
b) is based on temperature.
c) is based on the males being haploid and the females being diploid.
d) is based on the males being diploid and the females being haploid.
e) is opposite to that of humans, in that the mother has one copy of each of two different sex chromosomes.
a) mitosis and cytokinesis.
b) meiosis and cytokinesis.
c) fission and cytokinesis.
d) meiosis alone.
e) growth alone.
b) the central dogma.
c) the karyotype.
a) The Gap 2 phase immediately follows the Gap 1 phase.
b) Proteins are formed through all subphases of interphase.
c) Histones are synthesized primarily during DNA synthesis phase.
d) A cell can remain in Gap 1 for an hour, a day, a week, or a year.
e) It consists of mitosis and interphase.
a) the sex chromosomes but not the non-sex chromosomes.
b) the number, shapes, and sizes of chromosomes in an individual cell.
c) 23 pairs of chromosomes.
d) the shape of the spindle.
e) the non-sex chromosomes but not the sex chromosomes.
d) Synthesis (S phase)
f) interphase (Gap-1)
c) reverse transcriptase.
d) grape inhibition hormone.
e) cancer inhibition hormone.
a) The X chromosome has a full complement of genetic material, much of which is vital to life; the Y chromosome is missing the vast majority of these genes.
b) The X chromosome is capable of duplicating itself, so that the affected individual will eventually have two X chromosomes; the Y chromosome is incapable of duplicating itself.
c) 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.
d) A person with just an X chromosome would be a female, while a person with just a Y chromosome would not have a sexual identity.
e) The statement above is incorrect; it is possible to survive with just a Y chromosome, it’s just very rare.
a) is carried in a single linear chromosome.
b) is wrapped around proteins called histones.
c) is carried in multiple circular chromosomes.
d) is carried in a single circular chromosome.
e) floats freely in the cytoplasm. Most bacteria do not have chromosomes.
a) producing the female reproductive system
b) producing the smaller, more motile gamete
c) producing the larger, less motile gamete
d) producing the smaller, less motile gamete
e) producing more gametes
a) A single circular DNA helix is replicated into two identical circular DNA helices.
b) Four cells are produced from a single parent cell.
c) The chromosomes wind up into tight packages before cellular division.
d) Mitosis is used.
e) It is a form of sexual reproduction.
a) the sister chromatids fail to separate during meiosis I.
b) sister chromatids fail to separate during meiosis II.
c) the homologues all go into the same gamete during meiosis II.
d) the sister chromatids separate too soon in meiosis I.
e) the homologues fail to separate during meiosis II.
a) Gap 2 phase
b) Mitotic phase
c) DNA Synthesis phase
e) Gap 1 phase
a) The X chromosome is substantially larger than the Y chromosome.
b) Your maternal genes kill off your paternal genes at a greater rate than your paternal genes kill of your maternal genes.
c) You receive many mitochondria, which have their own genome, from your mother, but not from your father.
d) The maternal genes contain more dominant genes so they are expressed at least seventy percent of the time.
e) The above statement is incorrect. Fifty percent of the genetic material in your gametes comes from your father.
a) Radiation treatment will be most effective for the treatment of skin and stomach cancers.
b) Radiation therapy is an ineffective way to treat cancer.
c) Both skin and stomach cancer will be made worse if treated with radiation.
d) Both stomach and skin cells are constantly being replaced.
e) Radiation treatment will be ineffective in treating stomach cancer.
a) No, organisms that have lost normal telomere function are sterile.
b) Yes, scientists have succeeded in creating immortal rats through telomere treatments.
c) Yes, this is the subject of intense research.
d) No, aging in humans has more to do with gene mutation than telomeres.
e) No, cells that have lost normal telomere function are cancerous.
a) 64 pairs
c) Gap-1 (G1)
e) Gap-2 (G2)
f) Synthesis (S phase)
a) long limbs
b) web of skin between the neck and shoulders
c) XXY genotype
d) low testosterone levels
e) underdeveloped testes
a) underdeveloped ovaries
b) web of skin between neck and shoulders
c) X_ genotype
d) taller than average stature
e) some learning difficulties
a) exactly two copies of each chromosome.
b) one pair of each chromosome.
c) exactly one copy of each chromosome.
d) equal amounts of cytoplasm.
e) the same alleles.