Transcript Cell Growth

Warm-Up # 4
1/8/13
1) What is the difference between haploid and
diploid?
2) What are the two types of cell division?
3) How is meiosis different from mitosis?
4) Label the pictures below.
Grade Sheet
1/8/13
Unit 6 Vocab Quiz
Limits to Cell Growth, SA/V ratio
and the Cell Cycle
Unit 6
Cellular Reproduction
What are we learning?
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Essential Question
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Objectives:
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What happens to
cells when you grow
or get injured?
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Understand why a cell
divides
Limitations to cell
growth
Evaluate surface area
to volume ratio
Understand the cell
cycle
Fact:
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Sitting in the room….listening to me
ramble on, you have lost 40,000 skin cells.
But, you’re not naked. Why?
Cells reproduce
 We get bigger by producing more cells, not
bigger cells (SIZE DOESN’T MATTER!!!)
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Limits to Cell Growth
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Larger a cell
becomes, more
demands the cell
places on its DNA.
A large cell has
trouble moving
nutrients and waste
across the membrane
“Limits”
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DNA “Overload”
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Cell is small demand
is met
Cell is big
information crisis
“Cell Phone Towers”
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Exchanging Materials
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Food, oxygen, water
enter  waste leaves
Rate at which the
exchange takes place
depends on the
surface area of the cell
(total area of the cell
membrane)
Ratio of Surface Area to Volume
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Volume increases much more rapidly than
surface area (water balloon bursting)
This causes a decrease in the ratio of surface
area to volume (closer to 1)
 Therefore cells must divide
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Ratio of Surface Area to Volume in
Cells
Cell Size
Surface Area
(length x width x 6)
Volume
(length x width x height)
Ratio of Surface Area to
Volume
Cell Growth
1.
2.
Which cell is smaller; 10:1 or 6:1?
Which cell is more likely to divide; 2:1 or
3:1?
Remember!!!
The
surface area to
the volume ratio gets
smaller as the cell
gets larger.
Cell Cycle
Division of the Cell
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Cells divide into 2
“daughter” cells
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Called cell division
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Goal of cell cycle is for
each cell to copy its
genetic information
into another, new cell.
Starts With…
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Two general periods…
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Period of Growth—Interphase
 Cell
grows in size and carries on metabolism
 Chromosomes duplicate in preparation for Mitosis
(Each cell must copy its genetic information)
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Period of Division(Mitosis)—nucleus and then
its cytoplasm divides
Interphase—A Busy Time
Making ATP
 Repairing Themselves
 Excreting Waste
 Making Proteins
 Producing New Organelles
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Interphase Stages
G1
phase
S phase
G2 phase
Interphase Breakdown
G1Cell Grows
Protein
Production is
High
SG2Chromosomes Mitochondria
copy
and other
organelles are
manufactured
Preparation
for mitosis
Lets Review:
Give two reasons why cells divide.
 As a cell increase in size, which increase
more rapidly, its surface area or its
volume?
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Warm-Up #3
1)
2)
3)
4)
1/6/12
What are the two periods a cell goes
through in the cell cycle?
Which period takes longer?
Give two reasons a cell would not want
to get big, but divides instead.
If a cell has a height of 5 cm, a width of 5
cm and a length of 5 cm, what is its
surface area?
Cell Cycle Cut-Out
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Cut out the all pieces on your paper
Glue the pieces to your circle like on the board
Cut and glue the words on the cycle where they belong
On the back: explain what each step in mitosis does
Use pg. 155-157 to help you complete this
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Keep it in your folder to use on Monday’s quiz
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