Download Cell Cycle

Explain the following:
"It
is not a simple life to be a single
cell, although I have no right to say
so, having been a single cell so long
ago myself that I have no memory at
all of that stage of my life."
—Lewis Thomas (1913–1993) author,
biologist, physician
Cell Cycle
The Cell Cycle
A
period of growth, DNA replication
and cell division that MOST cells go
through
 Examples
of cells that don’t: nerve, brain and muscle
 Examples of cells that do: blood, intestinal and skin

Cell
Blood cells-2.4 million per second
Cycle is divided into 3 phases
Interphase
Mitosis
Cytokinesis
The Cycling Cell
Scientists used to think of interphase as a resting phase
during which not much happened, but they now know that
this is far from the truth. It is during interphase that
chromosomes—the genetic material—are copied and cells
typically double in size. While this is happening, cells
continue to do their jobs: Your heart muscle cells contract
and pump blood, your intestinal cells absorb the food you
eat, your thyroid gland cells churn out hormones, and so on.
In contrast, most of these activities cease during mitosis
while the cell focuses on dividing. But as you have probably
figured out, not all cells in an organ undergo mitosis at the
same time. While one cell divides, its neighbors work to keep
your body functioning.


http://publications.nigms.nih.gov/insidethecell/chapter4.html#10
INTERPHASE
Interphase
Longest
phase of the cell cycle
Consists of 3 distinct periods
G1
phase
Proteins
are produced, organelles
increase (multiply)
Cells grow during this phase, increase in
size
Cells acquire ATP (energy) for later use
S
phase
DNA
synthesis (DNA is replicated)
G2
phase
Changes
in cytoskeleton to prepare cell
for mitosis
Cell undergoes more growth
Cell acquires more energy (ATP)
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_the_cell_
cycle_works.html
INTERPHASE Specifics!
Nucleolus
is present
Individual chromosomes are NOT
visible (DNA is known as chromatin)
Nuclear membrane is present
Interphase
Mitosis
Nuclear
division, it is the process of
forming identical daughter cells by
replicating and dividing the original
chromosomes, in effect making a
cellular Xerox copy.

http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__mitosis_a
nd_cytokinesis.html
Prophase: 1st stage of mitosis
Chromatin
forms chromosomes (chromosomes
become visible)
Centrioles separate, start to move to opposite
ends
Spindle fibers form
Nuclear envelope (membrane) breaks down
Spindle fibers attach to centromeres
Chromatids
Referred
to as “sister” chromatids
Prophase
Metaphase: 2nd stage of
mitosis
Chromosomes
move to center of the cell
and line up in the middle of cell
Site where chromosomes gather is
called the metaphase plate
Metaphase
Anaphase: 3rd stage of mitosis
Shortest
stage of mitosis
Spindle fibers pull apart chromatids
Chromatids move to opposite ends of
the cell
Anaphase
Telophase: 4th stage of mitosis
End
of mitosis (terminal stage)
Spindle fibers (disassemble) break
apart
Nuclear envelope re-forms around
chromosomes
Chromosomes begin to break apart
Two identical nuclei exist in the cell
Nucleolus starts to re-form
Telophase
CYTOKINESIS
Division
of cytoplasm following mitosis
Results
in two daughter cells
Animal
Plant
cells?
cells?