Cell Reproduction

1
Cell Reproduction
2
Introduction

• Our bodies are constantly creating new cell parts
  to replace our damaged or dying cells. However,
  often we make too much material (more than we can
  use at the time) so our cell grow larger.

3
How Large Can A Cell Grow?

• Science fiction writers dream up huge cells that
  destroy cities, but this doesnt happen in real
  life. Different cells are different sizes
  depending on their function. There are limits to
  cell growth and it has to do with the cell
  membrane. Materials needed to support the cell
  enter through the membrane. There is an
  important relationship between the surface area
  of the cell membrane and the volume of the cell
  content.

4
Surface AreaVolume Ratio

• As an object increases in size its volume
  increases as the cube of its linear dimensions
  while surface area increases as the square. As
  these cubes illustrate, the surface area to
  volume ratio of a small object is larger than
  that of a large object of similar shape. This
  ratio limits how large cells can be.

5
What Would Happen If The Cell Kept Growing?

• Eventually, there would be too much volume and
  too little surface area to support life - the
  cell could starve to death by not receiving
  nutrients quickly enough or poison itself by not
  getting waste out quickly enough.

6
How Do Cells Keep From Reaching This Limit?

• In most cases, they divide. (Mitosis)

7
Cell Size Comparison
8
Cell Cycle

• Interphase
• Mitosis
• -Prophase
• -Metaphase
• -Anaphase
• -Telophase

9
Interphase

• Stage at which cell is carrying out normal life
  functions (growing, developing, etc.)
• Nucleolus nucleus visible
• Chromatin present
• Chromosomes replicate (amount of genetic material
  doubles)

10
Prophase

• Nucleolus disintegrates disappears
• Chromatin shortens thickens visible
  chromosomes
• Spindle fibers form
• Nuclear membrane disappears

11
Metaphase

• Separate spindle fibers attach to centromere of
  chromosome
• Chromosomes line up at center of cell (along
  cells equator)

12
Anaphase

• Centromeres split apart
• Sister chromatids are pulled to opposite ends of
  the cell

13
Telophase

• Chromotids reach opposite poles of the cell
• Nuclear membrane nucleolus reappear
• Chromosomes revert back to chromatin
• Animal - cell membrane pinches together 2
  identical daughter cells are formed
• Plant - cell plate forms and separates the cell
  into 2 identical daughter cells

14
Mnemonic Memory Device

• I Passed My Algebra Test
• Stages of the cell cycle in order
• Interphase - Prophase - Metaphase - Anaphase -
  Telophase

15
Mitosis Animation
16
The End!