Download The Cell Cycle and Mitosis

Mitosis and Cell Division
Cell Cycle and Mitosis
Interphase

Before Mitosis
 Cell Lives and
Grows
 Duplicates
chromosomes right
before mitosis
Prophase

Chromosome
condensation from
Chromatin
 Nuclear membrane
breaks down
 A microtubular
framework (the
Spindle apparatus)
forms with the help
of centromeres
Prophase
Spindle fibers
Disappearing
nuclear envelope
Doubled
chromosome
Prophase

The two halves of the
doubled structure are
called sister
chromatids.
 Held together by a
centromere.
Centromere
Sister
chromatids
Metaphase

During metaphase, the
chromosomes move to the
equator of the spindle.
Centromere
Sister
chromatids
Anaphase

During anaphase, the
centromeres split and
the sister chromatids
pulled apart to
opposite poles of the
cell.
Anaphase
Motor proteins
“walk” centromere
along microtubule.
 Tubulin removed
behind
centromere.

Anaphase

Evidence supports
hypothesis.
Anaphase

Cell elongation.
 Non
kinetichore microtubules join at
metaphase plate.
 Pushed by motor proteins away from each
other.
 Tubulin added to extend length.
Telophase

Nuclear envelope
reappears.
 Happens
simultaneously with
cytokinesis.
Nuclear
envelope
reappears
Two daughter cells are formed
Cytokinesis

Actual cell division
stage
 In animal cells, the
cell pinches in to form
the new cells.

Cleavage furrow of
actin and myosin.
Mitosis Animation
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
Click image to view movie.
Mitosis in Breast Cancer Cells
Reasons for Cell Division

Growth
 Increase
the size
or change the
shape or function
of a multi-cellular
organism.
Reasons for Cell Division

Repair
 Grow
new cells to
replace dead or
damaged ones.
Reasons for Cell Division

Reproduction



Prokaryotes (binary fission)
Single Cellular Protists
Multicellular eukaryotes



Plant vegetative propagation
Animal budding and
fission/regeneration
Parthenogenesis – eggs that
have the same number of
chromosomes as the mother.
Mitosis Review Animation
Mitosis Online Movie

http://www.allthingsscience.com/video/4
90/The-Stages-of-Mitosis
Question 1

Section 2 Check
The stringy structures in the cell nucleus that
contain DNA are __________.
A. centromeres
B. chromosomes
C. genes
D. chlorophylls
Section 2 Check

The answer is B.
Chromosomes are the
carriers of the genetic
material of the cell. A gene
is a segment of DNA that
controls the production of a
protein.
Question 2

Section 2 Check
Look at the diagram and identify the stage of
mitosis that is depicted.
A. prophase
B. metaphase
C. anaphase
D. telophase
Centromere
Sister
chromatids
The answer is B. Metaphase is the short
second phase of mitosis, during which the
chromosomes begin to line up on the
equator of the spindle.
Centromere
Sister
chromatids
Question 3
What is the process by which a cell's cytoplasm
divides?
A. cytokinesis
B. telekinesis
C. meiosis
D. mitosis
The answer is A. Cytokinesis follows
telophase and allows the two new cells to
separate.