Cell Membrane Strucutre 1. Phospholipid bilayer a. hydrophilic heads point out (phosphate) b. hydrophobic tails in center (fatty acid)

Cell Membrane Strucutre 2. Cholesterol a. keeps p-lipid from sticking together b. is a lipid so its hydrophobic

Cell Membrane Structure 3. Transport proteins a. protein tunnels through bilayer b. only let specific things in/out c. can open and close

2 Types of Cellular Transport 1) Passive Transport = no energy needed mol. flow high concentration  low conc. 2) Active Transport = takes energy molecules pumped Low conc.  high conc. Exocytosis/endocytosis

3 Types of Passive Transport all high conc.  low conc. 1) Diffusion (any molecule, random motion) 2) Facilitated Diffusion (diffusion through transport protein) 3) Osmosis (diffusion of water through membrane)

Diffusion

Facilitated Diffusion Molecules too big to fit btwn phospholipids must go through transport protein

Osmosis Diffusion of water must cross a membrane

3 Types of Active Transport can be low conc.  high conc. 1) Protein pumps (transport protein pushes molecules against conc. gradient) 2) exocytosis (cell membrane spits out molecules) 3) endocytosis (cell membrane takes in molecules)

Protein Pumps Protein pushes molecules into areas where they are in high concentration. ATP is the energy used

Terms for solute concentrations substance dissolved in water (sugar) Hypertonic solution = high concentration of solute Hypotonic solution = lower concentration

Isotonic solutions = same concentration of solute if mol. can pass through membrane…. they will do so until equal conc. on each side