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Mitosis
Eukaryotic Cell Division
The Cell Cycle
In 1858 Rudolph
Virchow witnessed what
millions of cells in your
body are doing right
now: Cells forming new
cells by a process of
division.
Why must our cells
divide?
WHY MAKE NEW CELLS?
Cells use division to maintain a small size
(optimum surface area to volume ratio).
Cells use division for Growth and repair.
Single-celled organisms use cell division for
asexual reproduction.
Prokaryotes Vs. Eukaryotes
During Cell division a parent cell
gives rise to two identical daughter
cells
Prokaryotes do not have a nucleus
so they undergo a simple division
called binary fission
Eukaryotes undergo a more complex
process where the nucleus needs to
split in a process called mitosis
Cell Cycle
Eukaryotic cell division is
broken into three main
parts Interphase,
Mitosis (Prophase,
Anaphase, Metaphase,
Telophase), and
Cytokinesis.
Cell Cycle
Interphase is the first
and longest phase of
Cell division
Three parts
G1-Growth
S –DNA Copied
G2- 2nd Growth:
make more organelle
Interphase
1. G1 (growth) phase:
a. Cell is growing and carrying out normal life
processes. Majority of a cells life is spent in
interphase.
Interphase: S Phase
2. S phase:
a. DNA is copied.
chromosomes consist of 2
identical DNA molecules
called sister chromatid.
Interphase: G2
3. G2 (growth) phase:
a. More growth and preparation for M phase.
(Mitosis)
M Phase-Mitosis
Mitosis is part of the
cell cycle that occurs
after Interphase.
During mitosis the
nucleus breaks down
and the genetic
material is divided
Mitosis: “M” Phase
Prophase
Mitosis can be
divided into
4 phases:
Metaphase
Anaphasse
Telophase
Prophase: Mitoisis Begins
Prophase is the longest phase in mitosis
Chromosomes condense and are visible.
Sister
Chromatids
Centromere
Prophase: Mitoisis Begins
In animal cells centrioles
appear and begin to move
to opposite ends of the
cell
Spindle fibers form
between the poles
Nuclear membrane
Disappears
Prophase
Prophase
Prophase
Metaphase
Chromatids attach to spindle
fibers and align at the middle
or equator of the cell.
Metaphase
Metaphase plate
Metaphase
Anaphase
Chromatids separate and
begin to move to the opposite
ends or poles of the cell.
Anaphase
Telophase
Nuclear membrane reforms so there are
two nuclei in the cell
Mitosis ends
Telophase
Cytokinesis: “C” Phase
Cytokinesis separates
animal cells into two
cells by forming a
cleavage furrow.
Each cell has its own
nucleus with identical
chromosomes.
Cytokinesis
Cytokinesis: “C” Phase
Because plants have a wall
they can’t form cleavage.
Cell plates form in plants
In the end, two separate
daughter cells produced with
single nucleus.
cell plate
Abnormal Cell Growth
Exposure to cigarette smoke and UV rays
from the sun can damage cells and cause
them to divide out of control
When Cells divide out of control it results
in cancer and the development of tumors.