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What is Mitosis?
• Mitosis: Cell division
involving somatic (nonsex) cells
• Involves only diploid cells
• End Result: Two
genetically identical
“daughter cells”
The Cell Cycle
• Defined:
Repeating set of
events in the life
of a cell
• 1) Interphase
– G1, S, G2
2) Prophase
3) Metaphase
4) Anaphase
5) Telophase
mitosis
•
•
•
•
Interphase
• Divided into 3 Stages:
• G1 Stage
– Normal function
performed
– Cell growth
– Organelles created
• S Stage
– Chromatin (DNA
strands) duplicated
• G2 Stage
– Cell growth
– Normal function
performed
Prophase
• 1st Mitosis Stage
• Chromatin (DNA
strands) coils into
chromosomes
• Nucleus dissolves
• Spindle fibers
form
Metaphase
• 2nd stage of
mitosis
• Spindle fibers
attach to
centromere of
chromosome
• Spindle fibers pull
chromosomes to
cell equator
Anaphase
• 3rd stage of mitosis
• Spindle fibers pull
½ the chromatids
to each end of the
cell
– Humans: 46
chromatids each
way
Telophase
• 4th stage of mitosis
• Spindle fibers
dissolve
• Chromatids unwind
into chromatin
• Nucleus reforms
• Cytokinesis:
division of the
cytoplasm
– NOT APPART OF
TELEPHASE
Nice animation of mitosis
Name that Stage!
Hint:
Chromosomes
are aligned in
middle of cell
Name that Stage!
Hint:
Cell plate is
splitting the cell
Name that Stage!
Hint:
Two normal
looking nuclei of
two cells
Name that Stage!
Hint:
Chromosomes
are forming and
the nucleus is
gone
Name that Stage!
Hint:
Chromatids are
being pulled
apart
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Name this stage of the cell cycle.
Mitosis
A Quick Overview
Aging
• Normal process
– Observable changes in the body’s structure & function
– Decreases the body’s ability to maintain homeostasis
• Cessation of mitosis
– Cells only divide a certain number of times & then stop
– May be programmed genetically
• Telomeres: Pieces of DNA found at the tips of each chromosome.
– Protect the chromosome from losing base pairs
– Guard against chromosomes sticking to each other
– Each time a cell divides its chromosomes’ telomeres shorten.
• After many divisions important parts of the DNA sequence may erode causing aging and or the death of
cells.
• Glucose
– Gets added to proteins inside & outside our cells creating links between cells
• Contributes to loss of elasticity and stiffening of tissues.
• Free radicals
– Cause damage to our carbon based molecules
– Enzymes produced by organelles in our cells are suppose to break them down
– Eating foods high in antioxidants (Vit C, E, betacarotene, selenium, etc) help combat the oxidation
REview
1) In order, name the 5 stages of the cell cycle.
2) Pick a stage of the cell cycle. Name 2 things that happen in this
stage.
3) Review the picture slides. Identify the stages based on the
picture.
4) The division of the cytoplasm is called _____.
5) Which cells divide by mitosis?
6) During which interphase stage is DNA created?
7) During which stage do spindle fibers form?
8) During which stage are chromosomes aligned in the middle?
9) During which stage are chromatids separated?
10) During which stage does the nucleus dissolve?
11) What are telomeres and what do they do?