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

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

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

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

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]

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?

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?

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

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

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!

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

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

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