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