Cell Growth

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Chapter 10

• Cell Growth Division

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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

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Limits to Cell Growth

• DNA overload
• DNA is unable to meet needs of a large cell
• Surface area to volume ratio
• Volume increases more rapidly than surface area
• Exchanging Materials
• The rate at which oxygen, food, waste are used
  up depends on the cells volume
• The rate at which oxygen, food, waste diffuse
  across the membrane depends on the cells surface
  area

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Division of the Cell

• Before cells become too big, they divide forming
  two daughter cells.
• The process of division is called cell division.

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10-2 Cell Division

• 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

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Purposes of Mitosis

1. Reproduction of unicellular organisms
2. Types of asexual reproduction
3. Growth / repair in multicellular organisms

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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!!

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Events of the Cell Cycle

• Interphase
• Has three phases G1, S, and G2
• Cell Grows
• Chromosomes replicate

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MITOSIS

• Prophase
• Longest Phase
• 50 60 of the total time of Mitosis
• Spindle Fibers Form
• Nuclear Envelope Disappears
• Chromosomes Coil up more tightly

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2) Metaphase

• Chromosomes line up across the center of the cell

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3) Anaphase

• Sister chromatids separate and move to opposite
  ends of the cell

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4) Telophase

• Chromosomes uncoil
• Nuclear Envelope reappears
• Spindle fibers disappear

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Cytokinesis

• Splitting of the cytoplasm into two cells!

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• Mitosis video (15 minutes)

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10-3 Regulating the Cell Cycle

• READ pages 250 253!
• Answer the following questions in your JOURNAL
• 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

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Modeling the Phases of the Cell Cycle (pg. 254)