2 Cell membraneDefine: The cell membrane regulates what enters and leaves the cell and also provides protection and support.Composition: Made up of a double-layered sheet called a lipid bilayerThe lipid bilayer gives the cell membrane a flexible structure that forms a strong barrier between the cell and its surroundings.The lipid bilayer also includes proteins used to channel molecules across and carbohydrates for communication.
4 Cell WallThe main function of the cell wall is to provide support and protection for the cellPlant cell walls are made up of cellulose
5 Quick Review Solution – A mixture of two or more substance Solvent – The liquid in which a solute is dissolved to form a solutionSolute – The substance dissolved in the solutionConcentration – The mass of a solute found in a volume of solution. Mass / Volume (g/L)
6 Transport Active Passive Transport across a membrane that requires the cell to use energyTransport across a membrane that requires the cell to use NO energy
7 DiffusionDiffusion is the process of particles moving from an area of high concentration to an area with low concentrationWhen the concentration of the solute is the same throughout a system, the system has reached equilibriumBecause diffusion depends upon random particle movement, substances diffuse across membranes without requiring the cell to use energy
9 FAcilitated diffusion Few molecules are too big to get through the membrane by themselves.Facilitated: Make an action or process easier.Facilitated diffusion: Molecules that cannot normally pass through the cell membrane get help using their own personnel protein channel.NO ENERGY REQUIRED!!!
10 Active Transport Uses energy Generally carried out by transport proteins or “pumps”“Pumps” work pumping concentration from low to high. (Backwards from normal)
11 OsmosisMost biological membranes are selectively permeable. Only allowing some substances through and denying others.Osmosis is the diffusion of water across a selectively permeable membrane.
12 How osmosis worksMovement of WATER from an area of high concentration to an area with low concentration.Water will continue to move across a membrane until equilibrium is complete.Isotonic – Same strength of soluteHypertonic – Above strength of soluteHypotonic – Below Strength of solute
13 Osmotic PressureFor cells to survive, they must find a way to balance the intake and outtake of water.If balance is not met, a force called osmotic pressure occurs. Creating a situation where cells will struggle to survive.