Chap 101 Cell Growth

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Chap 10-1 Cell Growth

• Limits to cell growth
• DNA Overload - if cell is too big there is not
  enough DNA to control it
• Exchanging materials - as cell gets bigger, its
  surface area/volume ratio goes down

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Chap 10-1 Cell Growth

• Large surface area/ Small surface area/
• volume ratio volume ratio
• Cells must obtain food and remove waste across
  cell membrane

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Cell Size
Surface Area (length x width x 6)
Volume (length x width x height)
Ratio of Surface Area to Volume
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Chap 10-2 Cell Division

• Cell Cycle - growth and division of cells
  G1, S, G2, and M phases
• Cell Division - cell divides into two daughter
  cells
• Interphase -
• G1 - increase in size of organelles
• S - DNA replication occurs
• G2 - preparation for mitosis

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Figure 104 The Cell Cycle
Section 10-2
G1 phase
M phase
S phase
G2 phase
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Chap 10-2 Cell Division

• M phase
• Mitosis - division of nucleus
• Cytokinesis - division of cytoplasm
• Length of cell cycle depends on G1.

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Definitions

• Chromatin - uncondensed DNA
• Chromosomes - condensed DNA
• visible only during cell division
• Chromatids - Replicated chromosomes still
  attached to each other.

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Definitions

• Diploid - Cell has normal number of chromosomes
• Haploid - Cell has half the normal number of
  chromosomes

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Definitions

• Centromere - Spot where chromatids are attached.
• Spindle - Collection of fibers that control
  movement of the chromosomes
• Centrioles - where spindle fibers attach

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Mitosis

• Prophase
• Chromosomes become visible
• Centrioles move to opposite sides of nucleus
• Nuclear membrane dissolves

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Mitosis

• Metaphase
• Spindle fibers attach to centromeres
• Chromosomes line up in center of the cell

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Mitosis

• Anaphase
• Centromeres separate
• Chromatids pulled to opposite sides of cell (now
  considered chromosomes)

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Mitosis

• Telophase
• Chromosomes decondense into chromatin
• Nuclear membrane reforms

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Cytokinesis - division of cytoplasm

• Plants cells - form CELL PLATE in center of cell
• becomes the new cell wall
• Animal cells - cell membrane drawn inward (like a
  string around a balloon)

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Cell Division

• Daughter cells are identical to each other and to
  parent cell (same number of chromosomes)
• M-phase is shortest phase of cell cycle
• Anaphase is shortest phase of mitosis

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Chap 10-3 - Regulating Cell Cycle

• Cyclins - proteins that regulate the cell cycle
• Normally, when cells stay in contact with other
  cells, growth and division are stopped

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Chap 10-3 - Regulating Cell Cycle

• Cancer - no control of cell growth, often due to
  defect in gene p53
• Tumor - mass of cells
• Cancer can occur in all multicellular organisms