Download PowerPoint- Introduction to Cell Division

Date: February 14th, 2017Happy Valentine’s Day!!
Aim # 49: Why do cells need to divide?
Do Now: Quick Write (1 minute)
Write down ANYTHING that comes to mind when
you hear the terms “Cell Division” Go!
HW:
1)Daily Review of Class Notes
2)All Labs due Friday
Aim #49: Why do cells need to
divide?
Compare the size of these organisms
Vs.
Vs.
1) Do these organisms have different size cells?
No, the cells of a large organism are
the same size of a small organism.
2) How do organisms get so big?
Cell
Division
3) Why do cells divide rather than grow
in size?
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+
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DNA “Overload”
Small Town
DNA Library
The larger the cell, the greater the
demands on the DNA library. Eventually,
the cell’s DNA would no longer be able
to serve the increasing needs of the
growing cell.
City
4) Exchange of Materials
What part of the cell is responsible for the
exchange of materials in and out of the cell?
Cell Membrane
The rate at which particles are able to move across the cell
membrane depends on the surface area of the cell
(the amount of the cell surface exposed to the environment).
SA
Rate of Exchange
5) Surface Area
Small particles have a relatively larger surface area than
large particles.
Why?
What will melt first?
The smaller chips
have more surface
area.
Vs.
Ice Cube
Ice Chips
Smaller cells have more surface area
and can exchange materials across
membrane more efficiently.
6) What is Cell Division?
The process by which a
cell divides into
2 new daughter cells.
7) What happens to chromosomes
before a cell divides?
The chromosomes are
replicated before a cell
divides.
8) What does replicate mean?
Replication is the
process by which DNA
makes a copy of itself
9) Why is it beneficial for daughter
cells to be smaller?
Smaller size of daughter
cells increases the surface
area and increases rate of
exchange of materials
across the membrane.
Chromosomes
What are chromosomes made
up of? DNA and Protein
The chromosomes are replicated
before a cell divides.
Centromere
Chromatids
Chromosome
Replication
Chromosome
2 Chromatids
+ Centromere
When do cells divide?
Organism Growth
Cells at the root tips divide very rapidly
When do cells divide?
Repair
12) What tissues in our body need
to undergo a lot of cell division?
Skin
Stomach
Why?
Bone
The cells of these tissues are
constantly growing or repairing
themselves.
Let’s Review…
1) What is cell division?
2) When do cells divide?
Process by which a cell divides
into 2 new daughter cells
GROWTH & REPAIR
3) When does DNA replication occur? BEFORE cell division
4) Draw a duplicated chromosome and label the
CENTROMERE and SISTER CHROMATIDS.
5) Why is it important that cells are small?
RATE
EXCHANGE
To increase the ________
of _______________
of
CELL
MEMBRANE_.
materials through the ________
_________
Chromosomes
Mitosis Images
Spindle Fibers
Mitosis is the process that divides the cell’s nucleus into two,
each with a complete set of genetic material from the parent cell.