Cell cycle (overviewof cell cycle) Flashcards
all living organisms are products of what?
repeated rounds of cell growth and division
cycle of duplication and division is known as the?
cell cycle
fundamental task of cell
the passing on of its genetic information to the next generation of cells
What are the 2 most basic function of the cell cycle
duplicate DNA and then segregate into two copies
What are the two major phases of the cell cycle?
(DNA synthesis) and M phase(mitosis and cytokinesis
two major events of M phase
Nuclear division, mitosis
Cytoplasmic division, or cytokinesis,
Early in mitosis at a stage called prophase
two DNA molecules are gradually disentangled and condensed into pairs of rigid, compact rods called sister chromatids, which remain linked by sister-chromatid cohesion
When the nuclear envelope disassembles later in mitosis, the sister-chromatid pairs become
attached to the?
mitotic spindle
in a stage called metaphase
Sister chromatids are attached to opposite poles of the spindle and, eventually, align at the spindle equator
start of anaphase
The destruction of sister-chromatid cohesion at the start of anaphase separates the
sister chromatids, which are pulled to opposite poles of the spindle
at telophase
The spindle is
then disassembled, and the segregated chromosomes are packaged into separate
nuclei
At Cytokinesis
cleaves the cell in two, so that each daughter
cell inherits one of the two nuclei
to allow time for growth, most cell cycles have?
gap phases
between M phase and S phase
G1 phase
between S phase and mitosis
G2 phase
four sequential phaseshase of eukaryotic cell cycle
G1 → S → G2 → M
occurs throughout the cell cycle, except during mitosis.
Cell growth
They are called interphase
G1, S, and G2
provide time for the cell to
monitor the internal and external
environment
gap phases
Why gap phases provide time for the cell to
monitor the internal and external
environment?
to ensure that conditions are
suitable and preparations are complete
before the cell commits itself to the major
upheavals of S phase and mitosis
-specialized resting state
- cell can remain for days, weeks, or even years before resuming proliferation.
G0 (G zero)
2 commitment point near the end of G1
Start (in yeasts) or the restriction point (in mammalian cells)
It is essentially the same in all eukaryotic
cells
basic organization of the cycle
What are the two mechanism that all eukaryotes appear to use similar to drive and regulate cell-cycle event
machinery and control mechanisms
budding yeast
Saccharomyces cerevisiae
fission yeast
Schizosaccharomyces pombe
What arevthe two simple eukaryotes in which powerful molecular and genetic
approaches can be used to identify and characterize the genes and proteins that
govern the fundamental features of cell division.
budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces
Its early embryos are excellent tools for biochemical dissection of cell-cycle control mechanisms
Xenopus laevis
useful for the genetic analysis of mechanisms
underlying the control and coordination of cell growth and division in multicellular organisms
Drosophila melanogaster
How can we tell what stage a cell has
reached in the cell cycle?
- to look at living cells with a microscope
- looking at budding yeast cells under a
microscope
-staining cells with DNA-binding fluorescent
dyes or with antibodies that recognize
specific cell components - using bromodeoxyuridine (BrdU) ti identify S phase
-by measuring its DNA content
very useful because the size of the bud provides an indication of cell-cycle stage
looking at budding yeast cells under a
microscope
provides an indication of cell-cycle stage
the size of the bud
recognize specific cell components such as the
microtubules
DNA-binding fluorescent dyes (which reveal the condensation of chromosomes
in mitosis) or with antibodies
can be identified in the microscope by supplying them with bromodeoxyuridine (BrdU)
S-phase
S-phase cells can be identified in
the microscope by supplying them with artificial thymidine analog called?
bromodeoxyuridine (BrdU)
Another way to assess the stage that a cell has reached in the cell cycle
by measuring its DNA content
measuring cell’s DNA content is
greatly facilitated by the use of?
flow cytometer
