1.When do cells use it? a)Growth b)Repair c)Replacement 2.Cell that reproduce by asexual...
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Transcript of 1.When do cells use it? a)Growth b)Repair c)Replacement 2.Cell that reproduce by asexual...
I. MitosisHappy Halloween!
Why do animals shed their skin?
A. Asexual Reproduction
1. When do cells use it?
a) Growthb) Repairc) Replacement
2. Cell that reproduce by asexual reproduction reproduce constantly.
B. Mitosis = Asexual Reproduction
1. Division of somatic cells (body)2. Process in which the nucleusdivides to form 2 new nuclei
Somatic Cell
Daughter Cells
Performed by a single (parent) cell
C. PURPOSE OF MITOSIS:
a. EXACTLY THE SAME KIND OF CHROMOSOMES
OF CHROMOSOMES.b. EXACTLY THE SAME NUMBER
1. TO PRODUCE TWO NEW NUCLEI WITH…
D. What are Chromosomes?
1. Organized structure of DNA in the cell
2. Located in the nucleus3. Usually are uncoiled in
the form of chromatin4. Only visible when the
cell divides and the chromatin condenses
5. Held together by a centromere
E. 5 Stages of the Cell Cycle(do not write)
InterphaseProphaseMetaphaseAnaphaseTelophase
**Animated Video**
1. Interphasea) Prior & After Mitosisb) G1 period
i. 90% of cell life spent here
ii. Cell goes about it’s business
c) S periodi. DNA is duplicated
d) G2 periodi. Cell prepares to divide
e) Cannot see DNA- uncoiled as chromatin
2. Prophase
a) DNA becomes visible as chromosomes
b) Nuclear membrane dissolves
c) Centrioles migrate to opposite poles
d) Spindle fibers form
Easy to remember- Prophase- prepares for mitosis
3. Metaphasea) Spindle fibers attach to
centromeresb) Chromosomes line up
at midline of the cell
Easy to remember- metaphase, DNA at middle
Spindle Equator
Pole
Pole
4. Anaphase
a) Spindle fibers pull apart centromeres
b) One chromatid goes to each centriole (they look like V’s)
Easy to remember- anaphase, away they go
5. Telophase
a) Chromatids reach centrioles
b) Mitosis ends when new nuclear membranes form
c) Some evidence of cell dividing
Easy to remember- telophase, terminal phase
6. Last part- Cytokinesis
a) Division of Cytoplasmb) Technically not in mitosis
i. Animal cell- pinching of cell membrane- cleavage
ii. Plant cell- formation of new cell wall- cell plate
iii. DNA becomes non-visible, back to chromatin
c) Daughter cells enter G1 period of interphase
The Cycle Just Keeps Going!
What Kind of Cells Does Mitosis Produce?
• Cells with a complete set of chromosomes called diploids
• Humans have 46 chromosomes or 23 pairs of chromosomes
• Human diploid # = 23• Most cells are diploid
Cancer
• Uncontrollable mitosis (no G1)– Cells cease to do what
they are supposed to be doing in favor of dividing.
• Cancer does not “poison” your body…
Henrietta Lacks• 1951, a poor 31 Year old African
American mother of 4 was dying of cervical cancer @ Johns Hopkins Hospital– Dr. George Gey- sampled some of the
cancerous cells, found they could live indefinitely and multiply outside the body
– She died 6 months later, but cells still live on
• HeLa cells– Used to study many different diseases– Polio Vaccine– How to transport cells
The Mitosis Shuffle!
• First, lets watch:University of Madison Mitosis Shuffle
• Your turn!“The Hustle” by Van McCoy
Homework• Mitosis Booklet – 3 pgs– 5 phases– 6 colors (one per chromosome)