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Cell Division
Chapter 3
Do Now
• What happens when you get a cut?
• Use pictures, symbols, words, etc. to
explain.
Objectives
• To list and explain the different reasons
cells must divide.
• To define chromosomes and all their
counterparts.
• To determine different things that limit
cell size.
Cellular Division
A. Cell division is involved in many
functions.
– 1. Unicellular division= “binary fission”
– 2. Multicellular division = “mitosis”
Binary Fission
http://www.youtube.com/watch?v=J6akNYlk
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Multicellular Division
http://www.youtube.com/watch?v=AhgRhXl7
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DO NOW
How big is a cell?
Why can’t a cell get too big?
Why do we need cell division?
Cell division is involved in many
processes.
a. Growth- get bigger
b. Development- change
c. Repair- fix damaged/old cells, cuts
d. Reproduction- make new cells
B. Cell Division is involved in growth,
development, and repair…
1.
All organisms start as
a single cell
a) Growth- limited by
surface area ( needs
high ratio of surface
area to volume)
b) High SA allows
nutrients in & waste
out
Surface area vs. volume
http://www.brown.edu/Courses/BI0020_Mille
r/week/10/web-1/4-2-2007_10-2026/Chapter_41/Present/Animations/41_A0
1/41_A01s.html
Cellular Growth
• Ratio of Surface Area to Volume
Area
Volume
Equations
• Surface Area:
• (2 x L x W) + (2 x L x H) + (2 x H x W)
• Volume:
• LxWxH
Do Now
Which cell has a bigger Surface Area to
Volume Ratio?
2x3x2
OR
4x1x1
Which cell is more efficient?
B. Cell Division is involved in growth,
development, and repair…
c. Development
i. makes cells that
are specialized
ex: nerve, blood,
muscle, bone
B. Cell Division is involved in growth,
development, and repair…
d. Repair
i. healing of cuts and wounds
ii. Cells divide to fill space and close
wound.
Chromosome Activity
1.
Worksheet
C. The genetic material of eukaryotic
cells is organized in chromosomes.
1.
DNA
(Deoxyribonucleic
Acid)
a. Discovered by
Watson, Crick, and
Franklin
1. purpose: hereditary
material (what
makes you you!)
b. Shape: Double Helix
1. Repeating units of
nucleotides
C. The genetic material of eukaryotic
cells is organized in chromosomes.
c. How does all of this DNA
fit in a cell?
50250
1. Loose= chromatin
2. Coiled around
proteins- chromosome
a. chromosome = 2
chromatids
-connected by a
centromere
Do Now
Label the parts of the chromosome.
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