question

What type of chromosomal abnormality leads to the phenotype known as Down syndrome? 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.

answer

b) trisomy 21

question

Using a light microscope, it is easiest to see chromosomes: 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.

answer

a) during mitosis and meiosis because the condensed chromosomes are thicker and therefore more prominent.

question

Hermaphrodites are organisms such as earthworms and garden snails that produce both male and female _________.

answer

gametes

question

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.

answer

apoptosis

question

Which of the following is TRUE about prokaryotic reproduction? 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.

answer

c) A single circular DNA helix is replicated into two identical circular DNA helices.

question

If DNA replication occurs by unwinding and rebuilding, then: 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.

answer

b) the two resulting DNA molecules each contain one original strand and one new strand.

question

Odometer is to an old, rusty car as __________ is to __________. 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

answer

a) telomere; a cell after 50 cell divisions

question

Mitosis results in: a) gametes. 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.

answer

c) daughter cells with the same number and composition of chromosomes.

question

Which of the following is NOT a disadvantage of sexual reproduction? 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.

answer

d) Variability among offspring enables parents to produce a range of offspring, any one of which may be suitable to changes in the environment.

question

Which of the following conditions is the result of too few sex chromosomes. a) Down syndrome b) "Metafemales" c) Turner syndrome d) Klinefelter syndrome e) "Super Males"

answer

c) Turner syndrome

question

_________ marks the break in the cell cycle between the end of mitosis and beginning of the synthesis stage. a) Gap 1 b) cytokinesis c) DNA Synthesis phase d) Gap 2 e) None of the above.

answer

a) Gap 1

question

Which of the following is the best way to distinguish male from female? 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.

answer

c) Males produce motile gametes.

question

Odometer is to an old, rusty car as __________ is to __________. 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

answer

d) telomere; a cell after 50 cell divisions

question

Which of the following is TRUE about meiosis in men and women? 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.

answer

a) Sperm production results in four cells from one starting cell; for eggs, only one egg results from one starting cell.

question

Without histones, eukaryotic DNA most likely would be: 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.

answer

a) much longer than it is.

question

Binary fission is to asexual reproduction as __________ is to __________. 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

answer

d) dividing into two; genetically identical offspring

question

During meiosis but NOT during 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.

answer

C

question

Which of the following is the BEST definition of a homologous chromosome? 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

answer

C

question

Which of the following does NOT occur during Prophase I of meiosis? 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.

answer

C

question

Which of the following is NOT a disadvantage of sexual reproduction? 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.

answer

A

question

Which is NOT true about a pair of homologous chromosomes? 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.

answer

D

question

How does crossing over introduce variation in meiosis? 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.

answer

A

question

Which of the following is the correct order of the stages of mitotoc cell cycle (starting with Interphase (Gap-1)? 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

answer

e) Interphase (Gap-1), S phase, Gap-2, Prophase, Metaphase, Anaphase, Telophase, Cytokenesis

question

Which of the following statements about the similarities and difference between chemotherapy and radiation therapy as cancer treatments is INCORRECT? 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.

answer

b) Radiation therapy has a significantly higher success rate than does chemotherapy.

question

During which phase of the cell cycle do the chromosomes align in one plane at the center of the cell? a) Interphase b) Prophase c) Metaphase d) Anaphase e) G2

answer

c) Metaphase

question

Eukaryotic cells can divide by: a) segregation only. b) replication only. c) mitosis only. d) meiosis only. e) both mitosis and meiosis.

answer

e) both mitosis and meiosis.

question

The interphase stage in the eukaryotic cell cycle has the subgroups: 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

answer

c) Gap 1, DNA Synthesis, and Gap 2.

question

In multicellular organisms, cells that undergo mitotic division but not meiotic division are called _____ cells. a) somosis b) skin c) germ d) somatic e) interphase

answer

d) somatic

question

Which of the following explains the fact that the Y chromosome carries nonessential information? 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.

answer

b) Women don't have a Y chromosome and are not genetically disadvantaged.

question

A karyotype: 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.

answer

e) Both a) and c) are correct.

question

In multicellular organisms, the cells that undergo mitotic cellular division but not meiotic cell division are called: a) somatic cells. b) somosis cells. c) interphase cells. d) germ cells. e) skin cells.

answer

a) somatic cells.

question

Cancer cells differ from normal cells in two important aspects: 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.

answer

e) indefinite cell division and the loss of contact inhibition.

question

Which of the following are the three stages of interphase (in the mitotoc cell cycle)? 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

answer

a) Gap-1, S-phase and Gap-2

question

Cytokinesis in both plant and animal cells results in the formation of which of the following? a) two haploid cells b) centromeres c) two daughter cells d) spindle fibers e) nuclear membranes

answer

c) two daughter cells

question

During meiosis, chromatin: 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.

answer

d) condenses, becoming more tightly coiled.

question

The planned process of cell suicide is called: a) denaturation. b) metastasis. c) apoptosis. d) mitosis. e) anastomosis.

answer

apoptosis.

question

Which of the following combinations of sex chromosomes is never seen in human beings? a) XXY b) YYY c) XXX d) XYY e) X_ (also written as XO)

answer

YYY

question

The chromosomes of bacteria are: a) circular. b) capsular. c) tetrahedral. d) linear. e) sickle-shaped.

answer

a) circular.

question

Bacteria reproduce asexually, whereas most plants and animals reproduce sexually. Which is the better method? 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

answer

e) Neither method is better—each is effective in different environments for different kinds of organisms

question

Down syndrome and other disorders where there are extra or missing copies of a chromosomes are the consequence of: a) mitosis. b) sex determination. c) fertilization. d) nondisjunction. e) crossing over.

answer

d) nondisjunction.

question

Nondisjunction: 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.

answer

a) is the unequal division of the genetic material during cell division.

question

Animal cells have "counters" that keep track of how many times a cell has divided. These counters are called: a) telomeres. b) nucleomeres. c) centromeres. d) odometers. e) chromosomes.

answer

a) telomeres.

question

Cytokinesis: 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.

answer

c) refers to the division of a cell's cytoplasm.

question

The majority of a eukaryotic cell's life is spent in an "in-between-division" stage referred to as: a) dormant phase. b) prophase. c) static phase. d) S phase. e) interphase.

answer

e) interphase.

question

Which of the following is TRUE about sex determination in humans? 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.

answer

d) The father's sperm determines the gender of a baby.

question

Which of the following is NOT true about the human karyotype? 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.

answer

e) It can be used to diagnose genetic diseases like cystic fibrosis

question

During DNA replication, each strand serves as a _____________ for the new ________________ strand. a) blueprint; template b) master model; transcribed c) template; complementary d) template; supplementary e) proofreader; complementary

answer

d) template; complementary

question

During metaphase II in meiosis a cell contains ________ of the DNA it did during prophase I. a) 1/4 b) 1/2 c) four times as much d) twice as much e) the same amount

answer

b) 1/2

question

DNA replication occurs during the _____________ phase of the cell cycle. a) mitotic b) DNA Synthesis c) cytokinesis d) Gap 1 e) Gap 2

answer

DNA Synthesis

question

Somatic cells can include: a) kidney cells. b) brain cells. c) sperm cells. d) All of the above are correct. e) Both a) and b) are correct.

answer

Both a) and b) are correct.

question

The process of cytokinesis often occurs simultaneously with which phase? a) telophase b) anaphase c) interphase d) prophase e) metaphase

answer

a) telophase

question

Cancer cells are different from other cells in that they have lost their "contact inhibition." "Contact inhibition" means: 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.

answer

e) most cells stop dividing when they bump up against other cells or collections of cells

question

Anaphase of mitosis occurs when: 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.

answer

a) the chromatids begin to separate from the metaphase plate.

question

Aneuploidy (an abnormal number of chromosomes) occurs due to one particular erroneous meiotic event called: 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).

answer

a) nondisjunction (chromosomes don't separate).

question

The DNA in linear eukaryotic chromosomes is wrapped around proteins called _____________, which keep the DNA from getting tangled and enable an orderly, tight, and efficient packing of the DNA inside the cell. a) histamines b) centromeres c) histones d) telomeres e) centrioles

answer

c) histones

question

During which stage of the mitotic cell cycle do 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) metaphase c) Gap-1 d) S-phase e) telophase

answer

e) telophase

question

Triplo-X syndrome is when a woman has an extra X chromosome. Using your knowledge of chromosomal inheritance, which of the following statements is most likely to be correct? 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.

answer

Both a) and d) are likely to be correct.

question

Sister chromatids line up at the center of the cell at which of the following phases of the mitotic cell cycle? a) Gap-2 b) cytokenesis c) Gap-1 d) prophase e) metaphase f) telophase g) S-Phase h) anaphase

answer

e) metaphase

question

Chromosomes on which recombination takes place: 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.

answer

Both a) and b) are correct

question

If a cell containing 20 chromosomes divides by mitosis, a total of how many daughter cells will be produced?

answer

2

question

Mitosis produces TWO (2) daughter cells that: 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.

answer

are genetically identical to each other and to the original parent

question

The Gap 1, DNA Synthesis, and Gap 2 phases of the cell cycle are collectively called: a) mitosis. b) cytokinesis. c) M phase. d) interphase. e) prophase.

answer

d) interphase.

question

Within interphase, which of the stages is defined by the active replication of the cell's genetic material? a) the mitotic phase b) the Gap 2 phase c) the Gap 1 phase d) the replication phase e) the DNA synthesis phase

answer

e) the DNA synthesis phase

question

In birds, sex determination: 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.

answer

a) is opposite to that of humans, in that the mother has one copy of each of two different sex chromosomes.

question

Which is the proper sequence of events in asexual cell division? 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

answer

d) interphase ; prophase ; metaphase ; anaphase ; telophase ; cytokinesis

question

Cytokinesis in both plant and animal cells results in the formation of which of the following? a) centromeres b) nuclear membranes c) two daughter cells d) spindle fibers e) two haploid cells

answer

c) two daughter cells

question

The enzyme DNA polymerase is most active during which of the following phases of the mitotic cell cycle? a) Gap-2 (G2) b) Gap-1 (G1) c) Anaphase d) Prophase e) Synthesis (S phase) f) Metaphase g) Cytokinesis h) Telophase

answer

e) Synthesis (S phase)

question

Chemotherapy is one common treatment for cancer. Which of the following are aspects of chemotherapy? 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.

answer

d) All of the above are correct.

question

Sister chromatids are: a) the result of crossing over. b) single-stranded. c) identical molecules of DNA resulting from replication. d) homologous chromosomes. e) produced in meiosis but not in mitosis.

answer

c) identical molecules of DNA resulting from replication.

question

A cell is said to have reached the metaphase stage of mitosis when: 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.

answer

the centromeres have arrived at the equatorial plate.

question

Down syndrome results from which of the following chromosomal abnormalities? 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

answer

all or part of a third copy of chromosome 21

question

Which of the following does NOT contribute to variability of the offspring in sexual reproduction? 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

answer

a brother and a sister producing children together

question

All of the following are cells that undergo mitosis, EXCEPT: a) skin cells. b) yeast. c) stomach cells. d) sperm cells. e) muscle cells.

answer

sperm cells.

question

If a cell containing 6 chromosomes divides by mitosis, how many daughter cells will be produced? a) 24 b) 12 c) 6 d) 2 e) 3

answer

2

question

The linear strands of DNA in eukaryotes are efficiently packed within the nucleus of the cell. The packing of DNA strands are mediated by proteins called: a) DNA polymerases. b) nucleosomes. c) topoisomerases. d) histones. e) barr bodies.

answer

histones.

question

A man having the "super male" genotype, meaning he has one extra Y-chromosome (XYY) marries a woman who is "meta female," having an extra X-chromosome (XXX). All of the following are possible genotypes of their children, EXCEPT: a) XY. b) XXY. c) YY. d) XX. e) XYY.

answer

yy

question

Which of the following is the direct product of DNA replication? a) cytokinesis 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

answer

...two sister chromatids

question

Which of the following is the BEST definition of a homologous chromosome? 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

answer

...one of two chromosomes of the same length and type inherited from a father or mother

question

DNA replication is facilitated by the fact that the base on one strand of the double helix (T, for example) always has the same partner (A, in this case) on the other strand. This feature of DNA is called: a) complementarity. b) transcription. c) translation. d) duplication. e) cytokinesis.

answer

complementarity.

question

The eukaryotic chromosome: 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.

answer

Both a) and b) can be correct, depending on whether replication has occurred

question

Genes are borne on structures called: a) gametes. b) alleles. c) cells. d) nuclei. e)

answer

chromosomes.

question

Which process is necessary to prevent the doubling of genome size during sexual reproduction? a) metastasis b) meiosis c) contact inhibition d) apoptosis e) mitosis

answer

meiosis

question

Between the stage in the cell cycle where the genetic material is replicated and the process of cell division begins there is a stage referred to as: a) Gap 3. b) Synthesis. 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.

answer

gap 2

question

The graph above shows the relationship between the incidence of Down syndrome in live births and the relationship to mother's age. 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.

answer

c) Because the number of births to women older than 45 is much smaller than births to younger women.

question

What is the difference between embryonic development and differentiation? 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.

answer

c) Development involves mitosis and embryonic growth; differentiation involves specialization of tissues.

question

Some fertility clinics now promise that a couple can choose the sex of their baby. What technique might allow for this? 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.

answer

both a and b are correct

question

The spindle begins to assemble at which of the following phases of the mitotic cell cycle?

answer

prophase

question

A karyotype is a physical representation (usually a photograph) of all of the chromosomes in a single cell; however, the cell must be in mitotic metaphase when the karyotype is made. Why? 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.

answer

d) Metaphase is the only stage of the cell cycle in which the chromosomes have condensed and aligned, but have not yet separated.

question

Which of the following does NOT occur in a cell during the mitotic cell cycle? 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

answer

sister chromatids pair up and join at the centromere

question

The ability for cancer cells to divide indefinitely is made possible because: 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.

answer

cancer cells rebuild their telomeres after every cell division.

question

During which phase of the mitotic cell cycle does reassembly of nuclear envelopes occur? a) S-phase b) anaphase c) telophase d) metaphase e) prophase

answer

telophase

question

If a cell containing 10 chromosomes divides by mitosis, how many chromosomes will be in each daughter cell?

answer

10

question

Crossing over takes place during: 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.

answer

prophase I of meiosis.

question

In many species of birds males are XX and females are XZ. With birds like this who is most likely to display a sex-linked recessive trait? a) males b) females 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.

answer

females

question

Errors sometimes occur when DNA duplicates itself. Why might that be a good thing? 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.

answer

New genes can enter the population and be acted upon by evolution.

question

Metafemales" are: 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.

answer

females with an XXX genotype.

question

In ants, sex determination: 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.

answer

is based on the males being haploid and the females being diploid.

question

The formation of a multicellular organism from a fertilized egg is called development. Development is accomplished through the processes of: a) mitosis and cytokinesis. b) meiosis and cytokinesis. c) fission and cytokinesis. d) meiosis alone. e) growth alone.

answer

mitosis and cytokinesis.

question

In some species, sex is determined by environmental, rather than genetic, factors. This is true of: a) humans. b) turtles. c) bees. d) kangaroos. e) birds.

answer

turtles

question

DNA replication is facilitated by the fact that the base on one strand of the double helix (T, for example) always has the same partner (A, in this case) on the other strand. This feature of DNA is called: a) translation. b) the central dogma. c) the karyotype. d) complementarity. e) transcription.

answer

complementarity.

question

Which of the following statements about the cell cycle is NOT true? 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.

answer

The Gap 2 phase immediately follows the Gap 1 phase.

question

A karyotype reveals: 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.

answer

the number, shapes, and sizes of chromosomes in an individual cell.

question

If a cell containing 8 chromosomes divides by mitosis, how many chromosomes will be in each daughter cell? a) 16 b) 4 c) 2 d) 26 e) 8

answer

8

question

The centromeres separate and the separated chromosomes move toward opposite poles of the cell during which of the following phases of the mitotic cell cycle? a) anaphase b) Gap-2 c) prophase d) Synthesis (S phase) e) telophase f) interphase (Gap-1) g) metaphase

answer

anaphase

question

Naturally occurring chemicals in plants may be useful in inhibiting cancer. One of these chemicals that is found in grapes and peanuts is called: a) erythropoietin. b) resveratrol. c) reverse transcriptase. d) grape inhibition hormone. e) cancer inhibition hormone.

answer

resveratrol.

question

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 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.

answer

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.

question

In most bacteria, the DNA: 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.

answer

d) is carried in a single circular chromosome.

question

What is the definition of "female"? 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

answer

producing the larger, less motile gamete

question

Which of the following is TRUE about prokaryotic reproduction? 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.

answer

A single circular DNA helix is replicated into two identical circular DNA helices

question

Nondisjunction is the unequal distribution of chromosomes during meiosis. Nondisjunction can occur at two different points. Either the homologues fail to separate during meiosis I or: 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.

answer

sister chromatids fail to separate during meiosis II.

question

If a cell becomes arrested within the cell cycle because it is unable to replicate its DNA, which of the stages would your predict it would become arrested in? a) Gap 2 phase b) Mitotic phase c) DNA Synthesis phase d) prophase e) Gap 1 phase

answer

Gap 1 phase

question

Seventy to ninety percent of the genetic material in a gamete made in your body could be inherited from your mother. How could this be? 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.

answer

You receive many mitochondria, which have their own genome, from your mother, but not from your father.

question

Radiation therapy for cancer works because a cell's DNA is exposed during mitosis and most vulnerable to damage from radiation. Because cancer cells are uncontrollably undergoing mitosis, they die when exposed to the treatment. The common side effects of radiation treatment are hair loss and vomiting. What does this imply? 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.

answer

Both stomach and skin cells are constantly being replaced.

question

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) 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.

answer

No, cells that have lost normal telomere function are cancerous.

question

The egg cells of a horse contain 32 chromosomes. How many chromosomes are in the horse's liver cells? a) 64 pairs b) 8 c) 64 d) 32 e) 16

answer

c) 64

question

The enzyme DNA polymerase catalyzes the DNA replication process during which of the following phases of the mitotic cell cycle? a) Telophase b) Prophase c) Gap-1 (G1) d) Anaphase e) Gap-2 (G2) f) Synthesis (S phase) g) Cytokinesis h) Metaphase

answer

f) Synthesis (S phase)

question

Which of the following is NOT a characteristic of Klinefelter Syndrome? a) long limbs b) web of skin between the neck and shoulders c) XXY genotype d) low testosterone levels e) underdeveloped testes

answer

b) web of skin between the neck and shoulders

question

Which of the following is NOT a characteristic of Turner Syndrome? a) underdeveloped ovaries b) web of skin between neck and shoulders c) X_ genotype d) taller than average stature e) some learning difficulties

answer

b) web of skin between neck and shoulders

question

Whether it is eggs or sperm being produced through meiosis, under normal circumstances, each gamete ends up with: 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.

answer

c) exactly one copy of each chromosome.

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