CELL MEMBRANES & DIFFUSION

MIXTURE TWO OR MORE ELEMENTS THAT ARE PHYSICALLY MIXED TOGETHER

FLUID AND NONDISSOLVED MATERIAL SUSPENSION

ALL COMPONENTS ARE EVENLY DISTRIBUTED AND DISSOLVED SOLUTION

SOLUTE SUBSTANCE BEING DISSOLVED Substance that dissolves the solute SOLVENT

SOLUTE SUBSTANCE BEING DISSOLVED Substance that dissolves the solute SOLVENT

AMOUNT OF SOLUTE PER SOLVENT Mass / Volume CONCENTRATION

MOVES FROM EVERYTHING HIGH TO LOW

MOVEMENT FROM HIGH TO LOW CONCENTRATION Concentration Gradient: the differences in concentration of two mediums ↑ Concentration Gradient = ↑ Diffusion DIFFUSION

Osmosis : the diffusion of water

CONCENTRATION OF SOLUTE IS THE SAME THROUGHOUT THE SYSTEM EQUILIBRIUM

TONICITY DIFFERENCE IN WATER CONCENTRATION OF TWO SOLUTIONS SEPARATED BY A PERMEABLE MEMBRANE HYPERTONIC MORE SOLUTES IN THE AREA HYPOTONIC LESS SOLUTES IN THE AREA ISOTONIC EQUAL AMOUNTS

10% STARCH 30% STARCH HYPERTONIC = WATER DIFFUSES OUT OF CELL, CELL SHRINKS

30% STARCH 10% STARCH HYPOTONIC = WATER DIFFUSES INTO CELL, CELL EXPANDS

20% STARCH ISOTONIC = NO NET MOVEMENT

Cytoplasm Cytoskeleton Nucleus Nucleolus Ribosomes Rough E.R. Smooth E.R. Plasma Membrane Golgi Apparatus Mitochondria Vacuole Lysosome

The Plasma Membrane of cells are made up of a PHOSPHOLIPID BILAYER Hydrophilic Head Hydrophobic Tails “water-loving” “water-fearing” PHOSPHOLIPID BILAYER

The Plasma Membrane of cells also have PROTEINS and CHOLESTEROL Help movement across the membrane; protein channels Detect materials outside the cell Help keep the membrane fluid and wavy

___IN___ Nutrients -sugars (glucose) -proteins -fats Salts O2O2 H2OH2O ___OUT___ Waste - ammonia - salts - CO 2 Products - Proteins H2O

INSIDE OUTSIDE Uncharged smaller particles can pass through the membrane Charged particles (+/-) or large particles cannot LIPIDS O2 CO2 SALT +/- WASTES STARCH

Large and/or charged particles must use Transport Proteins or Protein Channels to pass through the plasma membrane

Simple Diffusion Facilitated Diffusion Simple Diffusion vs. Facilitated Diffusion Move from HIGH to LOW through a transport protein Move from HIGH to LOW directly through the lipid bilayer Passive Transport : diffusion occurs down the Concentration Gradient

Sometimes, transport needs to occur AGAINST the Concentration Gradient Example: Glucose Cells must use ACTIVE TRANSPORT to go against the gradient

Active Transport uses ATP Energy to push materials from LOW to HIGH concentration

Simple Diffusion Facilitated Diffusion Passive Transport Active Transport

shipping out of the cellshipping into the cell

How does endocytosis and exocytosis work?