Chapter 9 Cell Cycle MB

In dividing cells, most of the cell's growth occurs during ___.

interphase

Nucleoli are present during _____.

interphase

During mitosis, microtubules attach to chromosomes at the______.

kinetochore(s)

During prophase, the microtubules of the mitotic spindle _______. disassemle, shorten, or lengthen

lengthen

During anaphase, the nonkinetochore microtubules_______ and move past each other, and the kinetochore microtubules _______. disassemble, shorten, or lengthen

lengthen....shorten

Can you match these prefixes, suffixes, and word roots with their definitions?

single: haplo both, double: diplo- same: homo- (or homeo-) without, lack of, not: a- (or an-) small: micro- to produce: -gen- body: -some (or soma-) chromosomes: ploid color: chrom- self: auto- many: multi- end: telo- before: pro- two: bi- one: uni- between: inter- segment, body section: -mere thread: mito- cell: -cyte (or cyto-) moving: kin- (or kinet-)

DNA replication produces two identical DNA molecules, called _______, which separate during mitosis.

sister chromatid(s)

Cytokinesis often, but not always, accompanies _____.

telophase

During _____ both the contents of the nucleus and the cytoplasm are divided

the mitotic phase

Cytokinesis in animal cells is accomplished by constriction of the cell along the plane of cell division (formation of a cleavage furrow). In plant cells, which have cell walls, a completely different mechanism of cytokinesis has evolved.

-Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate. -The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells.

When is DNA condensed

G1- no S- no G2 - no beginning of M ( prophase to early anaphase) - yes end of M (late anaphase to telophase) - yes

When does the cell contain twice as much DNA as it did in G1 phase

G1- no S- yes G2 - yes beginning of M ( prophase to early anaphase) - yes end of M (late anaphase to telophase) - yes

When are sister chromatids present

G1- no S- yes G2 - yes beginning of M ( prophase to early anaphase) - yes end of M (late anaphase to telophase) - no

Which of these is NOT a carcinogen? testosterone cigarette smoke UV light fat all of the above are carcinogens

all of the above are carcinogens

Centromeres divide and sister chromatids become full-fledged chromosomes during _____.

anaphase

In all cells, separation of replicated chromosomes is a prerequisite for cell division. However, the mechanism of chromosome separation in bacteria is distinct from that in eukaryotes in several ways.

bacteria only: chromosome separation begins at the origin of replication on DNA eukaryotes only: before separation duplicated chromosomes condense, nuclear envelope fragments permitting chromosome separation, two copies of the duplicated chromosome are attached at their centromeres before separating both bacteria and eukaryotes: chromosomes replicate before cell division, replicated chromosomes separate by attaching to some other structural feature of the cell

The ______ are the organizing centers for microtubules involved in separating chromosomes during mitosis.

centrosome(s)

After chromosomes condense, the _______ is the region where the identical DNA molecules are most tightly attached to each other.

centromere(s)

During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called ____.

chromatin

In most eukaryotes, division of the nucleus is followed by _____ when the rest of the cell divides

cytokinesis

During telophase, the nonkinetochore microtubules _______. disassemble, shorten, or lengthen

disassemble

_____ is a carcinogen that promotes colon cancer. fat UV light estrogen a virus testosterone

fat

The ______ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division.

mitotic spindle(s)

Spindle fibers attach to kinetochores during _____.

prometaphase

Chromosomes become visible during _____.

prophase

Mitosis unfolds through a sequence of stages marked by specific events in the cell. The structural changes in the cell are brought about by a series of tightly coordinated underlying mechanisms.

prophase: cohesions join sister chromatids of duplicated chromosome, tubulins assemble into spindle microtubules prometaphase: microtubules attach to kinetochores metaphase: kinetochores are motionless in relation to poles of cell anaphase: cohesions break down, kinetochores move toward poles of cell telophase: spindle microtubules disassemble

During prophase a homologous pair of chromosomes consists of _____.

two chromosomes and four chromatids