2 Cell Membrane Cell membrane regulates what leaves and enters the cell. It is a lipid bilayer with proteins embedded in the layer.
3 Phospholipids Phosphate head- polar “likes” water Lipid tail- 2 fatty acids- non-polar- does not “like” water
4 Phospolipid Bilayer There are 2 types of proteins in the lipid bilayer Integral Proteins- transport substances across membranePeripheral Proteins- bind to the bilayer temporarily, perform various cellular processes.
5 Phospholipid BilayerCholesterol plays an important role in maintaining the integrity of the membrane.Keeps it firm and from becoming too permeable.Carbohydrates- Act as cell markers, allow cells to identify each other.
7 DiffusionAll cells must exist in a liquid environment in order to survive.A solution is a mixture of two or more substances.Solute- substance dissolved into the solventSolvent- substance solute dissolves into.Ex- iced tea mix is the solute, water is the solvent
8 Diffusion Particles are constantly moving in a solution. Particles tend to move from an area of high concentration to an area of low concentration, this is called diffusion.Movement from high to low concentration is called the concentration gradient
10 EquilibriumParticles move from high to low conc. until they are the same throughout the system, this is called equilibrium
11 DiffusionSince particle movement is random, diffusion occurs across the membrane without the use of energy.Called Passive Diffusion
12 OsmosisOsmosis is the diffusion of water across a selectively permeable membrane.
13 OsmosisWater will move across a membrane until the concentrations of water and the solute are equal, this is an isotonic solution.Hypertonic solution- when there is more solute then water. concentratedHypotonic solution- when there is more water then solute. dilute
15 Facilitated Diffusion Proteins in the cell membrane allow some substances pass through easier then others.Still follows concentration gradientEx- doorman at a club, lets some people in easier then others
16 Active TransportSometimes particles have to move from low to high concentration, against the concentration gradient.This requires energy and is called active transport.Ex- swimming against the current of a river.Use proteins to carry particles across