1. Chapter 3 Cells Physiology
Do you remember learning about?
Membrane Transport
-Passive
-Active

2. Fill in as we go Membrane Transport
Movement into and out of cells to maintain HOMEOSTASIS
Filtration
Fill in as we go

3. Cellular Fluids Solution Intracellular fluid Interstitial fluid
Solvent – dissolving medium (ex. water)
Solutes – what gets dissolved (ex. sugar, salt)
Intracellular fluid
inside cell
Interstitial fluid
- outside cell

4. Passive Processes Diffusion Molecules ALWAYS moving; Brownian motion
Movement from high to low concentration, or down a concentration gradient
Equilibrium - concentration is equal/balanced.

5. Membrane is Selective Permeability
Allows some materials to pass, not all
3 types of diffusion in cells
Simple diffusion - lipid-soluble or small - to pass through pores
Facilitated diffusion - too big or not lipid-soluble; need protein carriers (channel or gated proteins)
Osmosis - movement of water across membrane from [hi] to [lo]

6. 1. Which substance(s) can move through the membrane? Why?
Study the diagram below. It represents a container that is divided by a semi permeable membrane. A different solution in its initial state is shown on each side of the membrane.
1. Which substance(s) can move through the membrane? Why?
2. Which direction will the molecule(s) will move? To side I or II?
3. Which substance will move across fastest? Why?
4. How long will the molecule(s) will continue to move?

7. Osmosis - How Cells Respond to Different Solutions
10% solute
85% H2O
15% solute
95% H2O
5% solute
90% H2O
10% solute
90% H2O
10% solute
90% H2O
10% solute
Isotonic
(no net movement
of water)
Hypotonic
Hypertonic
What solution would you give someone who is retaining water?

8. Why shouldn’t you drink ocean water if you are thirsty?

9. Another Passive Process
Filtration
Water & solutes forced through a membrane by pressure
Pressure gradient
(high to low)
Happens in kidneys.

10. Active Transport Processes
Transport substances that can’t pass because:
too large
not lipid-soluble
against concentration gradient
2 common forms of active transport
Solute pumping
Bulk transport
Energy (ATP)
required!

11. Solute pumping Amino acids, some sugars and ions are pumped
ATP energizes protein carriers, moves substances against concentration gradients (from low to high, or up a gradient concentration.
Sodium-Potassium
Pumps

12. Bulk Transport Exocytosis Endocytosis Moves out of cell by vesicle
engulfed by vesicle & brought in
2 Types
Phagocytosis – cell eating
Pinocytosis – cell drinking

13. High to Low Any direction as needed Protein Pumps Filtration
Channel or Gate Proteins
Pressure through capillaries
Protein Pumps
Anything dissolved in blood
Water, urea, sugars, ions