Chapter 7 review

After the chromosome has coiled to becomevisible in the nucleus, most of what you areseeing is actually

a. DNAb. RNAc. Histone proteinsd. Cyclinse. None of these

Answer: c

As a result of the cyclin-kinase complex, enzymes are turned on that destroy cyclins.This is an example of

a. competitive inhibitionb. non-competitive feedbackc. feedback inhibitiond. an endothermic reactione. none of these

Answer: c

How do the daughter cells at the end of mitosiscompare with their parent cell when it was in G2 of the cell cycle?

a. The daughter cells have half the amount of chromosomes and the same amount of DNA.b. The daughter cells have half the amount of chromosomes and half the amount of DNA.c. The daughter cells have the same number of chromosomes and half the amount of DNA.d. The daughter cells have the same number of chromosomes and the same amount of DNA.e. The daughter cells have the same number of chromosomes and twice the amount of DNA.

Answer: c

Cells that have stopped dividing and are differentiating are

a. cancer cells.b. in the G1 phase of the cell cycle.c. in the G2 phase of the cell cycle.d. in the S phase of the cell cycle.e. in the M phase of the cell cycle.

Answer: b

The last part of the metamorphosis of a tadpole to an adult frog results in the disappearance of the tail. This stage of development most likely occurs by

a. cells of the tail dying and the nutrients being absorbed and reused by the body

b. shedding of the tail so energy is not spent on maintenance of an unneeded part

c. bilateral division of the tail and fusion with the developing hind limbs

d. individual cells of the tail migrating to the developing gonads

Answer: a

Measurements of the amount of DNA pernucleus were taken on a large number of cellsfrom a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus.One nucleus had 5 picograms of DNA. Whatstage of the cell cycle was this cell in?

a. G1b. Sc. G2d. Me. cannot tell from data

Answer: b

Centrioles began to move apart in animal cellsat what phase?

a. prophaseb. prometaphasec. metaphased. anaphasee. telophase

Answer: a

Centromeres uncouple, sister chromatids areseparated, and the two new chromosomesmove to opposite poles of the cell in this phase.

a. prophaseb. prometaphasec. metaphased. anaphasee. telophase

Answer: d

A spermatocyte produces the following four sperm cells. These cells are the result of nondisjunction during which of the following phases?

a. Interphase (G1 or G2)b. Interphase (S)c. Mitosisd. Meiosis Ie. Meiosis II

Answer: d

N+1 N+1 N-1 N-1

All of the following are characteristics of telophase of mitosis EXCEPT

a. each chromosome is made of twochromatids.b. cytokinesis begins.c. the nuclear envelop reappears.d. chromosomes begin to uncoil.e. a cell plate begins to form in plant cells.

Answer: a

Which of the following occurs duringmitosis but not during meiosis I?

a. The chromosomes are pulled to opposite poles of the spindle fibers.

b. The chromatids of each chromosome are separated.

c. Both synapse and crossing-over take place.

d. The nuclear envelope breaks down.Answer: b

A cell containing 92 chromatids at the start ofmitosis would, at its completion, produce cellscontaining how many chromosomes?

a. 12b. 16c. 23d. 46e. 92

Answer: d

A cell containing 92 chromatids at the start ofmeiosis would, at its completion, produce cellscontaining how many chromosomes?

a. 12b. 16c. 23d. 46e. 92 Answer: c

Taxol is an anticancer drug extracted from thePacific yew tree. In animal cells, taxol disruptsmicrotubule formation by binding to microtubulesand accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stopsmitosis. Specifically, taxol must affect

a. the fibers of the mitotic spindles.b. anaphase.c. formation of the centrioles.d. chromatid assembly.e. the S phase of the cell cycle.

Answer: a

Which of the following is true of a species thathas a chromosome number of 2n=16?

a. The species is diploid with 32 chromosomes.b. The species has 16 different types ofchromosomes.c. There are 16 homologous pairs.d. During the S phase of the cell cycle,there will be 32 separate chromosomes.e. A gamete from this species has 8chromosomes.

Answer: e

Nondisjunction during meiosis can cause all ofthe following EXCEPT

a. Down syndrome.b. Klinefelter syndrome.c. trisomy 13.d. sickle cell anemia.e. 45, XX -21

Answer: d

a. The statement is true for mitosis only.b. The statement is true for meiosis I only.c. The statement is true for meiosis II only.d. The statement is true for mitosis and meiosis I.e. The statement is true for mitosis and meiosis II.

1.This occurs when a cell divides to form two cells that are genetically identical.2. Centromeres uncouple and chromatids areseparated from each other.3. Independent assortment of chromosomesoccurs.4. Tetrads line up on the midline. Answer: b

Answer: a

Answer: e

Answer: b

Crossing-over occurs during which phase ofMeiosis?

a. prophase Ib. metaphase Ic. anaphase Id. prophase IIe. both a and b

Answer: a

All of the following are differences betweenspermatogenesis and oogenesis EXCEPT?

a. Spermatogenesis uses mitosis whereasoogensis uses meiosis.b. Spermatogenesis is an equal divisionwhereas oogenesis is not.c. Spermatogenesis is complete beforefertilization, oogenesis is not.d. Spermatogenesis occurs more frequentlythan oogenesis.e. Spermatogenesis creates 4 viable cellswhereas oogenesis creats only 1 viablecell. Answer: a

During late telophase and cytokinesis, a cellplate forms in

a. animal cellsb. plant cellsc. neitherd. bothe. plants, animals, and bacteria

Answer: b

Which of the following have centrioles?

a. animal cellsb. plant cellsc. neitherd. bothe. plants, animals, and bacteria

Answer: a

Which of the following can use meiosis as a means of reproduction?

a. animal cellsb. plant cellsc. neitherd. bothe. plants, animals, and bacteria

Answer: d

A biologist counted 2,500 cells from an embryo on a microscope slide and recorded the following data.

Stage Number of CellsProphase 125Metaphase 50Anaphase 50Telophase 25Interphase 2,250Total 2,500

If these cells had been dividing totally randomly, it could be reasonably concluded that

a. the duration of telophase is approximately one-half that of anaphase.

b. prophase is approximately three times as long as telophase.

c. metaphase is the shortest stage of the cell cycle.

d. interphase is the shortest stage of the cell cycle.

Answer: a

Genes that are close to each other on a chromosome will

a. show a high rate of crossing over.b. show a low rate of crossing over.c. show a high rate of crossing over onlyif near the centromeres.d. never cross overe. none of these

Answer: b

The rate of division of most vertebrate cells is LEAST likely to be influenced by which of the following?

a. Contact with other cellsb. The availability of nutrientsc. Compounds that inhibit protein synthesisd. The cell’s photoperiode. The temperature of the organism

Answer: d

The result of meiosis in angiosperms is the production of

a. gametes.b. a haploid sporophyte.c. a diploid sporophyte. d. a diploid gametophyte.e. haploid megaspores and microspores.

Answer: e