Ch. 7: Cell Transport

1
Ch. 7 Cell Transport

• Definitions
• Solute
• Solvent
• Solution
• Passive vs. Active transport

2
Cell Transport

• Passive Transport Diffusion
• Solutes (or solvents) moving down their
  concentration gradient high low
• Natural tendency, no energy required
• Atoms/molecules always are in constant random
  movement, when they hit something bounce
  back in the opposite direction

3
Diffusion

• What affects diffusion or how fast diffusion
  occurs?
• Temperature
• Concentration gradient
• Particle size

4
Cell Membrane (Plasma Membrane)

• Selectively permeable
• Small uncharged particles can cross such as gases
  (Oxygen and carbon dioxide gas) and water.
• Charged particles (sodium ions, chloride ions,
  etc.) cannot cross or are slowed.
• Large particles cant get through.

5
Osmosis (diffusion of water)

• Diffusion of water across a selectively permeable
  membrane.
• Hypertonic
• Hypotonic
• Isotonic
• Equilibrium

6
Facilitated Diffusion

• Diffusion with the aid of a carrier protein.
• Eg.

7
Active Transport

• Requires energy
• Pumps
• To maintain a concentration gradient
• From low conc. to high conc.
• Against the natural tendency
• Na/K pumps pump Na out, K in
• Ca pumps, H pumps, Cl- pumps
• Endocyotosis
• Pinocytosis
• phagocytosis
• Exocytosis