1. Section 3-3: Cell Processes
Cells
Section 3-3: Cell Processes

2. Metabolism
The sum of all building-up and breaking-down activities that occur in a living cell

3. Respiration
The process in which simple food substances such as glucose are broken down and the energy they contain captured in high energy molecules that can be used as fuel by the cell

4. Aerobic Respiration Requires oxygen Occurs in the mitochondria
C6H12O O CO2+ 6H2O +energy
(glucose) (ATP)

5. Aerobic Respiration
Although the equation is simple the process is complicated, involving many different molecules and many steps

6. Anaerobic Respiration
Does not use oxygen
Provides much less energy
Fermentation (such as the process used to make wine) is a form of anaerobic respiration
Used by yeast that produce alcohol and carbon dioxide

7. Photosynthesis Occurs in chloroplasts Also a very complex process
6CO2+ 6H2O + energy C6H12O6 + 6O (glucose)
The energy is captured from light by chlorophyll

8. Diffusion
The process by which molecules of a substance move from an area of higher concentration of that substance to areas of lower concentration of that substance
Occurs because of the constant motion of molecules that causes them to spread out until they are evenly distributed in the available volume

9. Diffusion
Is a physical process that does not require the input of energy from a living organism A B C

10. Diffusion into a Cell
Diagram by Mariana Ruiz Villarreal, released to public domain

11. Osmosis The diffusion of water into or out of a cell
Many single-celled organisms that live in fresh water use contractile vacuoles to pump excess water out of the cell. The water enters the cell by osmosis.

12. Semi-permeable Membranes
Cell membranes are semi-permeable or selectively permeable
This means that only certain molecules can diffuse through them including:
Water
Oxygen
Carbon dioxide
Small food molecules

13. Osmosis Lower Concentration of Water Molecules
Higher Concentration of Water Molecules
Of Salt
Of Salt

14. Active Transport
The process by which a cell moves molecules into and out of the cell that cannot diffuse through the membrane
Requires energy to work

15. Active Transport
One method uses special transport molecules (proteins) that pick up a specific substance on one side of the membrane and moves it to the other side
This is how ions of calcium (Ca), potassium (K) and sodium (Na) move

16. Active Transport
Diagram by Mariana Ruiz Villarreal, released to public domain

17. Active Transport
A second type of active transport is called phagocytosis.
A cell surrounds a food particle with a pocket of cell membrane which pinches off into the cell to form a food vacuole

18. Active Transport-Phagocytosis
Drawing of an ameba engulfing a bacterium