chapter 10 bio 203

In animal cells, cytokinesis occurs via the formation of a cell plate. __________________

ANS: F, cleavage furrow

Bacteria divide asexually by mitosis. __________________

F binary fission

1. A nucleosome consists of DNA wrapped around scaffolding proteins. __________________

F histone

Microtubules of the mitotic spindle attach directly to each chromosome at the centromere. __________________

F kinetochore

TFor each animal cell that begins oogenesis, the number of ova produced is four. __________________

F two

Cell-cycle checkpoints temporarily block key events from being initiated during the cell cycle. __________________

T

Enzymes required for DNA replication are synthesized during the G1 phase. __________________

T

The members of each homologous pair of chromosomes separate during meiosis I. __________________

T

The cell cycle of a typical somatic cell consists of __________ and M phase. a. interphase b. meiosis I c. crossing-over d. meiosis II e. mitosis

a

Which of the following represents the overall sequence of events during mitosis? a. prophase - metaphase - anaphase - telophase b. interphase - metaphase - anaphase - telophase c. anaphase - telophase - metaphase - interphase d. interphase - prophase - anaphase - metaphase e. metaphase - telophase - anaphase - prophase

a

Each nucleosome has __________ base pairs of DNA wrapped around a disc-shaped core of eight histone molecules. a. 146 b. 28 c. 18 d. 10,000 e. 456

a. 146

Once nerve cells become mature, they don't usually undergo cell division. Based on your knowledge of the cell cycle, you would predict that mature nerve cells become arrested in the __________ of the cell cycle. a. G0 phase b. S phase c. prophase d. G1 phase e. G2 phase

a. G0 phase

What is the function of nucleosomes? a. To prevent DNA strands from tangling. b. To help DNA replicate. c. To make RNA synthesis possible. d. To prevent RNA from tangling with DNA during transcription. e. To prevent histones from tangling.

a. To prevent DNA strands from tangling

A maternal homologue and a paternal homologue synapse to form: a. a tetrad. b. a parental pair. c. a paternal pair. d. sister chromatids. e. a maternal pair.

a. a tetrad.

During prophase, __________ is(are) compacted into visible chromosomes. a. chromatin b. centrioles c. centromeres d. kinetochores e. colchicine

a. chromatin

The sources of genetic variation during meiosis are: a. crossing-over and the random assortment of maternal and paternal chromosomes. b. crossing-over and random pairing of tetrads. c. random pairing of tetrads and mutations. d. polyploidy and random pairing of tetrads. e. random pairing of tetrads and random assortment of maternal and paternal chromosomes

a. crossing-over and the random assortment of maternal and paternal chromosomes.

Nucleosomes are best described as: a. eukaryotic DNA associated with histone proteins. b. prokaryotic DNA associated with nonhistone proteins. c. eukaryotic DNA associated with nonhistone proteins. d. prokaryotic DNA associated with histone proteins. e. eukaryotic DNA associated with scaffolding proteins

a. eukaryotic DNA associated with histone proteins.

What evolutionary advantage is provided by sexual reproduction? a. increased genetic diversity b. making clones c. making diploidy possible d. making polyploidy possible e. being able to work with chromosomes

a. increased genetic diversity

If a cell is in G2: a. it has twice the amount of DNA present in a telophase nucleus. b. it has visibly distinct chromosomes. c. it lacks a visible nuclear membrane. d. it is in mitosis. e. it is in cytokinesis.

a. it has twice the amount of DNA present in a telophase nucleus.

Chromosomes are condensed to their greatest extent during __________ of mitosis. a. metaphase b. prophase c. telophase d. interphase e. anaphase

a. metaphase

The M phase of the cell cycle involves two main processes: a. mitosis and cytokinesis. b. meiosis I and meiosis II. c. homologous pairing and crossing-over. d. interphase and mitosis. e. mitosis and meiosis.

a. mitosis and cytokinesis.

Gametophyte plants produce gametes using: a. mitosis. b. meiosis. c. fertilization. d. polyploidy. e. sporogenesis

a. mitosis.

The formation of female gametes is termed: a. oogenesis. b. macrogenesis. c. spermatogenesis. d. ovogenesis. e. microgenesis.

a. oogenesis.

Refer to Figure 10-2. The process occurring at arrow 3 in the associated figure is: a. fertilization. b. G1. c. meiosis. d. mitosis. e. fusion

a.fertilizaion

Refer to Figure 10-2. The chromosome complement of item 6 in the life cycle is: a. twenty. b. haploid. c. diploid. d. forty-eight. e. four.

b haploid

An animal with a diploid number of 36 chromosomes will have __________ chromosomes in its gametes and __________ chromosomes in its somatic cells. a. 18; 18 b. 18; 36 c. 36; 18 d. 36; 36 e. 36; 72

b. 18; 36

A bacterial chromosome consists of: a. a linear DNA molecule many times larger than the cell. b. a circular DNA molecule many times larger than the cell. c. a circular DNA molecule smaller than the cell. d. a linear DNA molecule smaller than the cell. e. a linear or circular DNA molecule smaller than the cell.

b. a circular DNA molecule many times larger than the cell.

Cytokinesis in animal cells involves contraction of a ring of __________ microfilaments. a. tubulin plus actin b. actin plus myosin c. cyclin plus myosin d. keratin plus actin e. cyclin plus actin

b. actin plus myosin

A zygote contains the __________ complement of chromosomes. a. haploid b. diploid c. polyploid d. spermatogenesis e. none of these

b. diploid

Sporophyte plants produce spores using: a. mitosis. b. meiosis. c. fertilization. d. macrogenesis. e. microgenesis.

b. meiosis.

During which phase does crossing-over occur? a. interphase b. prophase I c. metaphase I d. prophase II e. metaphase II

b. prophase I

Homologous chromosomes undergo synapsis during: a. anaphase I. b. prophase I. c. anaphase II. d. telophase II. e. prophase II

b. prophase I.

In a human cell at prophase I, there are __________ tetrads. a. 92 b. 46 c. 23 d. 2 e. 4

c. 23

Chromosomes are duplicated during __________ of the cell cycle. a. G1 phase b. G2 phase c. S phase d. metaphase e. prophas

c. S phase

Plant hormones known as __________ stimulate mitosis. a. gametophytes b. kinesin and dynein c. cytokinins d. colchicines e. kinetochores

c. cytokinins

Which of the following events does not occur in prophase II? a. formation of the spindle b. condensation of chromatin into chromosomes c. formation of chiasmata d. removal of the nuclear membrane e. sister chromatids become visible when viewed with the light microscope.

c. formation of chiasmata

Eukaryotic chromosomes consist of: a. circular DNA molecules complexed with positively charged nonhistone proteins. b. circular DNA molecules complexed with negatively charged histone proteins. c. linear DNA molecules complexed with positively charged histone proteins. d. linear DNA molecules complexed with negatively charged histone proteins. e. circular DNA molecules

c. linear DNA molecules complexed with positively charged histone proteins.

The correct number of chromosomes is maintained during sexual reproduction by: a. a process by which one half of the chromosomes in gametes are removed. b. chromosome doubling in the newly formed zygote. c. meiosis, which reduces the chromosome number by half. d. mitosis, which maintains the original chromosome number. e. replication of chromosomes twice during meiosis

c. meiosis, which reduces the chromosome number by half.

The __________ is responsible for the separation of the chromosomes during __________ of mitosis. a. cell wall; anaphase b. flagellum; metaphase c. mitotic spindle; anaphase d. kinetochore; prophase e. centromere; telophase

c. mitotic spindle; anaphase

Which of the following events does not occur during meiosis I?a. crossing-over and the random assortment of maternal and paternal chromosomes. a. DNA exchange b. pairing of homologous chromosomes c. separation of sister chromatids d. separation of homologous chromosomes e. crossing-over between homologous chromosome

c. separation of sister chromatids

During prophase I of meiosis, homologous chromosomes lie side by side. This phenomeon is known as: a. chromatid pairing. b. divalent formation. c. tetrad formation. d. paternal pairing. e. parental pairing

c. tetrad formation.

A cell is in metaphase if: a. the chromosomes are visible as threadlike structures. b. the nuclear envelope is clearly visible. c. the chromosomes are aligned at the midplane of the cell. d. the chromosome are separated into distinct groups at opposite poles of the cell. e. cytokinesis is occurring.

c. the chromosomes are aligned at the midplane of the cell.

Generation time refers to: a. the number of years it takes for a generation to die. b. the amount of time required to replicate the DNA in a cell. c. the time it takes to complete one cell cycle. d. the time required for an individual in a species to achieve sexual maturity. e. the time it takes for a new mitotic spindle to form.

c. the time it takes to complete one cell cycle.

The kinetochore serves which of the following functions? a. Kinetochores anchor spindle fibers to the centrioles. b. Kinetochores are the site of DNA synthesis. c. Kinetochores regulate the length of the cell cycle. d. Kinetochores attach to microtubules during mitosis. e. Kinetochores are involved in cytokinesis.

d. Kinetochores attach to microtubules during mitosis.

During prophase I, each chiasma represents: a. the remnants of the nuclear membrane. b. the remnant of the nucleolus. c. a newly formed haploid gamete. d. a site of crossing-over. e. the site where sister chromatids are connected.

d. a site of crossing-over.

During which of the following stages of meiosis do the sister chromatids separate? a. metaphase I b. anaphase I c. metaphase II d. anaphase II e. telophase II

d. anaphase II

Plant clones can be produced by: a. sexual reproduction. b. fertilization. c. gamete production. d. asexual reproduction. e. binary fission

d. asexual reproduction.

If meiosis did not occur in sexually reproducing organisms, then: a. growth of the zygote would be halted. b. mitosis would be sufficient. c. gametes would remain haploid. d. chromosome number would double in each generation. e. eggs would be haploid, but sperm would be diploid.

d. chromosome number would double in each generation.

Animal cells are stimulated to divide by mitosis by: a. colchicines. b. magnetic fields. c. mating. d. growth factors. e. nutrients.

d. growth factors.

The chromosome makeup of an individual organism is called a: a. kinetochore. b. chromosome plot. c. centromere. d. karyotype. e. centriole.

d. karyotype.

Nucleosomes are organized into large coiled loops held together by: a. histones. b. centromeres. c. kinetochore proteins. d. scaffolding proteins. e. condensins.

d. scaffolding proteins.

Most human somatic cells are: a. polyploid. b. diploid. c. aneuploid. d. tetraploid. e. haploid.

diploid

Which of the following statements concerning the cell cycle is FALSE? a. The activity of Cdks increases and decreases during the cell cycle. b. Cyclins fluctuate during the cell cycle. c. Cdks are active only when they bind to cyclins. d. The anaphase-promoting complex stimulates the separation of sister chromatids e. M-Cdk inhibits mitosis

e. M-Cdk inhibits mitosis

__________ contain identical DNA sequences and are held together by __________ during mitosis. a. Daughter chromosomes; hydrogen bonding b. Daughter chromosomes; ionic bonding c. Sister chromatids; spindle fibers d. Sister chromosomes; histone proteins e. Sister chromatids; centromeres

e. Sister chromatids; centromeres

To prevent disastrous consequences, the eukaryotic cell cycle is controlled by: a. the mitochondria. b. helper viruses. c. environmental signals. d. a very detailed, rigid genetic program. e. a series of cell cycle checkpoints

e. a series of cell cycle checkpoints

Duplicated centrioles move to opposite poles of a dividing __________ cell during __________ of the cell cycle. a. plant; metaphase b. plant; anaphase c. prokaryotic; metaphase d. animal; interphase e. animal; prophase

e. animal; prophase

Cytokinesis in plant cells occurs via the formation of a(n): a. aster. b. mitotic spindle. c. Golgi complex. d. cell wall. e. cell plate

e. cell plate

The mitotic spindle is made of: a. collagen. b. condensin. c. histones. d. keratin. e. microtubule

e. microtubule

If a cell is dividing by binary fission then you know that: a. mitosis has taken place without cytokinesis. b. homologous chromosomes have already paired. c. the cyclin-Cdk complex is no longer phosphorylating enzymes. d. the cell cycle is out of control. e. the cell is prokaryotic.

e. the cell is prokaryotic.

All of the following events occur during prometaphase EXCEPT: a. the nuclear envelope breaks down. b. the nucleoli disappear. c. the mitotic spindle is completely assembled. d. the spindle fibers "capture" chromosomes. e. the duplicated chromosomes become visible with the light microscope.

e. the duplicated chromosomes become visible with the light microscope.

Which of the following are NOT produced by meiosis? a. polar bodies b. animal eggs c. animal sperm d. plant spores e. zygotes.

e. zygotes.

A pair of centrioles is found at the center of the microtubule-organizing center in plant cells. _________________

f animal cells