Chapter 7 review

After the chromosome has coiled to become visible in the nucleus, most of what you are seeing is actually a. DNA b. RNA c. Histone proteins d. Cyclins e. 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 inhibition b. non-competitive feedback c. feedback inhibition d. an endothermic reaction e. none of these Answer: c

How do the daughter cells at the end of mitosis compare 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 d. The daughter cells have the same number 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 per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. One nucleus had 5 picograms of DNA. What stage of the cell cycle was this cell in? a. G1 b. S c. G2 d. M e. cannot tell from data Answer: b

Centrioles began to move apart in animal cells at what phase? a. prophase b. prometaphase c. metaphase d. anaphase e. telophase Answer: a

Centromeres uncouple, sister chromatids are separated, and the two new chromosomes move to opposite poles of the cell in this phase. a. prophase b. prometaphase c. metaphase d. anaphase e. 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. Mitosis d. Meiosis I e. Meiosis II N+1 N+1 N-1 N-1 Answer: d

All of the following are characteristics of telophase of mitosis EXCEPT a. each chromosome is made of two chromatids. 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 during mitosis 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 of mitosis would, at its completion, produce cells containing how many chromosomes? a. 12 b. 16 c. 23 d. 46 e. 92 Answer: d

A cell containing 92 chromatids at the start of meiosis would, at its completion, produce cells containing how many chromosomes? a. 12 b. 16 c. 23 d. 46 e. 92 Answer: c

Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stops mitosis. 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 that has a chromosome number of 2n=16? a. The species is diploid with 32 chromosomes. b. The species has 16 different types of 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 8 Answer: e

Nondisjunction during meiosis can cause all of the 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. This occurs when a cell divides to form two cells that are genetically identical. 2. Centromeres uncouple and chromatids are separated from each other. 3. Independent assortment of chromosomes occurs. 4. Tetrads line up on the midline. Answer: a Answer: e Answer: b Answer: b

Crossing-over occurs during which phase of Meiosis? a. prophase I b. metaphase I c. anaphase I d. prophase II e. both a and b Answer: a

All of the following are differences between spermatogenesis and oogenesis EXCEPT? a. Spermatogenesis uses mitosis whereas oogensis uses meiosis. b. Spermatogenesis is an equal division whereas oogenesis is not. c. Spermatogenesis is complete before fertilization, oogenesis is not. d. Spermatogenesis occurs more frequently than oogenesis. e. Spermatogenesis creates 4 viable cells whereas oogenesis creats only 1 viable cell. Answer: a

During late telophase and cytokinesis, a cell plate forms in a. animal cells b. plant cells c. neither d. both e. plants, animals, and bacteria Answer: b

Which of the following have centrioles? a. animal cells b. plant cells c. neither d. both e. plants, animals, and bacteria Answer: a

Which of the following can use meiosis as a means of reproduction? a. animal cells b. plant cells c. neither d. both e. 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 Cells Prophase 125 Metaphase 50 Anaphase 50 Telophase 25 Interphase 2,250 Total 2,500 If these cells had been dividing totally randomly, it could be reasonably concluded that Answer: a 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.

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 only if near the centromeres. d. never cross over e. 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 cells b. The availability of nutrients c. Compounds that inhibit protein synthesis d. The cell’s photoperiod e. 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