Chapter 10

A cell is committed to progressing through the cell cycle through to mitosis once it transitions from ____. a. G2 to prophase b. G1 to S c. S to G2 d. telophase to cytokinesis e. G1 to G0

b. G1 to S

How many unique chromosomes does an organism with a chromosome number of 4n=32 have? Assume that none of these are sex chromosomes, and do not count any duplicate homologous chromosomes in this number. a. 8 b. 64 c. 4 d. 16 e. 32

a. 8

Which statement characterizes cancer cells? a. Cancer cells display uncontrolled cell division. b. Cancer cells behave like normal cells. c. Cancer cells form tumors that adhere strongly to surrounding tissues. d. Tumors formed by cancer cells remain encapsulated and only grow in one location. e. Mitosis in cancer cells is strictly regulated.

a. Cancer cells display uncontrolled cell division.

At the conclusion of mitosis, each daughter cell has ____. a. DNA identical to the parent cell b. half the DNA and half the cytoplasm found in the parent cell c. DNA genetically different from the parent cell d. twice the cytoplasm and the same amount of DNA as the parent cell e. twice the amount of DNA and half the cytoplasm of the parent cell

a. DNA identical to the parent cell

Centriole replication occurs during ____. a. S phase b. telophase c. prophase d. G1 phase e. G2 phase

a. S phase

Duplicated centrioles move to opposite poles of ____ cell during ____ of the cell cycle. a. an animal; prophase b. an animal; metaphase c. a plant; metaphase d. a plant; prophase e. both animal and plant cells; prophase

a. an animal; prophase

The microtubule organizing center (MTOC) of an animal cell is an identifiable structure known as the ____. a. cell plate b. chromosome c. centromere d. kinetochore e. centrosome

e. centrosome

Where is the centromere found? a. central region of a chromosome where the spindle microtubules attach b. center of the cell where the nucleus is found during prophase c. position where metaphase chromosomes align d. location where chromosomes cluster during telophase e. location where the mitotic spindle forms

a. central region of a chromosome where the spindle microtubules attach

Oncogenes are often ____. a. mutant forms of cell cycle genes b. required for normal contact inhibition of cells c. not involved in cell division d. normal forms of cell cycle genes e. needed for normal cells to metastasize

a. mutant forms of cell cycle genes

During the mitotic spindle checkpoint, ____. a. proper spindle attachment to chromosomes is assessed b. cells are in anaphase c. cells enter G0 d. cells become irreversibly committed to S phase e. cells arrest if chromosomes are attached properly to the mitotic spindle

a. proper spindle attachment to chromosomes is assessed

Chromatin condenses into chromosomes and the mitotic spindle begins to form during ____. a. prophase b. metaphase c. telophase d. anaphase e. interphase

a. prophase

At the conclusion of S phase, a diploid cell with 40 chromosomes will have ____ chromosomes and _____ sister chromatids. a. 20; 40 b. 40; 80 c. 40; 40 d. 20; 20 e. 80; 80

b. 40; 80

Most cancers require at least two mutations: 1) one in an oncogene, which encodes proteins that trigger cell division, and 2) one in a tumor suppressor gene, whose protein products, in their unmutated form, play a key role in preventing the cell cycle from progressing if the DNA is damaged or in the absence of specific cues. Which class of proteins might be considered tumor suppressors? a. cyclins b. Cdk inhibitors c. microtubules d. transcription factors e. growth factor receptors

b. Cdk inhibitors

Generally, which phase of the cell cycle varies the most in length? a. All phases are the same length among cells b. G1 c. G2 d. S e. M

b. G1

Progression through the phases of the cell cycle is regulated by fluctuating concentrations of ____. a. actin b. histones c. cyclin-dependent kinases d. microtubules e. cyclins

e. cyclins

Karyotype analyses are performed on cells in ____ of mitosis. a. prometaphase b. telophase c. metaphase d. prophase e. anaphase

c. metaphase

One of the three internal cell cycle checkpoints occurs during ____ and monitors ____. a. anaphase; the presence of DNA damage b. late S phase; the presence of DNA damage c. the G2/M transition; the presence of DNA damage d. the G2/M transition; mitotic spindle integrity e. the G1/S transition; mitotic spindle integrity

c. the G2/M transition; the presence of DNA damage

A plant cell with three sets of chromosomes is ____. a. hexaploid b. tetraploid c. triploid d. diploid e. haploid

c. triploid

In early experiments to understand the control of the cell cycle, researchers fused HeLa cells that were at different stages of the cell cycle. What did the results of these experiments suggest? a. Microtubules play an essential role in the progression of the cell cycle. b. The cell cycle has three checkpoints through which the cell must pass in order to progress through to mitosis. c. The concentrations of cyclins fluctuate throughout the cell cycle. d. Molecules in the cytoplasm control the progression of the cell cycle. e. The concentrations of cyclin dependent kinases (Cdks) fluctuate throughout the cell cycle.

d. Molecules in the cytoplasm control the progression of the cell cycle.

Loosely packed regions of DNA associated with histones are called ____. a. chromosomes b. 30-nm chromatin fibers c. nucleosomes d. euchromatin e. heterochromatin

d. euchromatin

The separation of duplicated chromosomes into two new nuclei is known as ____. a. cytokinesis b. fertilization c. meiosis d. mitosis e. binary fission

d. mitosis

If a cell has 36 chromosomes at the beginning of G1, how many chromosomes will be present at the end of G2? a. 18 b. 64 c. 44 d. 72 e. 36

e. 36

Replication of DNA occurs during ____. a. G1 phase b. cytokinesis c. G0 phase d. prophase e. S phase

e. S phase

When growth factors bind to receptors on the cell surface, the signaling cascade will ____. a. trigger mitosis without the other stages of the cell cycle b. cause the cells to enter the G0 state c. prevent cell division d. trigger cell death e. initiate cell growth

e. initiate cell growth

Which sequence of the cell cycle is correct? a. anaphase, interphase, telophase, prometaphase, prophase, metaphase b. prophase, metaphase, interphase, telophase, anaphase c. interphase, metaphase, prometaphase, prophase, telophase, anaphase d. prometaphase, anaphase, prophase, telophase, interphase, metaphase e. interphase, prophase, prometaphase, metaphase, anaphase, telophase

e. interphase, prophase, prometaphase, metaphase, anaphase, telophase

Colchicine, a chemical extracted from the autumn crocus (Colchicum autumnale), inhibits the formation of microtubules. Mitotic cells exposed to colchicine will therefore be arrested at ____. a. interphase b. telophase c. anaphase d. prophase e. metaphase

e. metaphase

The microtubules of the mitotic spindle originate from the ____ in both plant and animal cells. a. centromere b. centriole c. chromatid d. centrosome e. microtubule organizing centers (MTOCs)

e. microtubule organizing centers (MTOCs)

Replication of a bacterial chromosome begins at a specific region called the ____. a. ter b. replication fork c. rep d. beg e. ori

e. ori

What is the role of Cdks? a. to allow the cell cycle to work forward or backward b. to check for proper attachment of spindle fibers to chromosomes c. to remove phosphate groups from cyclins d. to arrest the cell cycle e. to add phosphate groups to target proteins

e. to add phosphate groups to target proteins