Transcript Chapter 10 - Duplin County Schools

Chapter 10
Cell Growth &
Division
10-1 Cell Growth
 Question: Are cells in a mouse and a
whale the same size??
 INTEREST GRABBER (10-1)
 The larger a cell becomes, the more
demands the cell places on its DNA. In
addition, the cell has more trouble moving
enough nutrients and wastes across the
membrane
Limits to Cell Growth
1) DNA “overload”
 DNA is unable to meet needs of a large cell
2) Surface area to volume ratio
 Volume increases more rapidly than
surface area
3) Exchanging Materials
 The rate at which oxygen, food, & waste
are used up depends on the cell’s volume
 The rate at which oxygen, food, & waste
diffuse across the membrane depends on
the cell’s surface area
Division of the Cell
 Before cells become too big, they divide
forming two “daughter” cells.
 The process of division is called cell
division.
10-2 Cell Division
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In eukaryotic cells, genetic information
is passed on from one generation to the
next by chromosomes.
Chromosomes are made of DNA
Human cells have 46 chromosomes
Purposes of Mitosis
1) Reproduction of unicellular organisms
2) Types of asexual reproduction
3) Growth / repair in multicellular organisms
The Cell Cycle
 The cell cycle is a series of event that
cells go through as they grow and divide.
 During the cell cycle, a cell …
– Grows
– Prepares for division
– Divides to form 2 daughter cells
 Each of which begin the cell cycle again!!
Events of the Cell Cycle
 Interphase
– Has three phases: G1, S, and G2
– Cell Grows
– Chromosomes replicate
MITOSIS
1) Prophase
 Longest Phase
 50 – 60% of the total
time of Mitosis
 Spindle Fibers Form
 Nuclear Envelope
Disappears
 Chromosomes Coil
up more tightly
2) Metaphase
Chromosomes line up across the center of
the cell
3) Anaphase
 Sister chromatids separate and move to
opposite ends of the cell
4) Telophase
 Chromosomes uncoil
 Nuclear Envelope reappears
 Spindle fibers disappear
Cytokinesis
 Splitting of the cytoplasm into two cells!
 Mitosis video (15 minutes)
10-3 Regulating the Cell Cycle
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READ pages 250 – 253!
Answer the following questions in your
JOURNAL:
1.
2.
3.
4.
5.
What is Cancer and what causes it?
Can cell division be turned on and off?
What does Cyclin do?
What are stem cells?
Do you believe stem cell research should be
allowed? Briefly support your answer
Modeling the Phases of the Cell Cycle (pg. 254)