2 Cell Membrane Cell membrane = controls what enters and leaves the cellprovides protection and supportReceives chemical signalsAll cell membranes are made up of a double layer known as a lipid bilayer.
3 The Structure of the Cell Membrane Section 7-3Outsideof cellInside(cytoplasm)CellmembraneProteinsProteinchannelLipid bilayerCarbohydratechainsTo concept map
4 Cell Walls Cell wall = provides support and protection for the cell the cell wall is found in plant and fungi cells not animal cells
5 Measuring concentration The cytoplasm of a cell contains many different substances in waterThe substances dissolved in the solution are called solutesThe concentration of a solution is the mass of the solute in the volume of solutionExample: 12 grams of salt in 4 liters of water is 12g/3LThe concentration is 3g/L
6 Diffusion In a solution molecules move constantly and randomly Diffusion = molecules tend to move from an area of high concentration to an area of low concentration to spread outWhen the concentration in the solution is the same throughout it is at equilibriumDiffusion happens without having to use energy
7 OsmosisMany substances can diffuse across the membrane bus some are too large or strongly charged and cannot cross.Water moves easily across the membraneOsmosis = is the diffusion of water through a selectively permeable membraneWater will move across the membrane until equilibrium is reached, at that point the concentration of water and solute will remain the same. This will mean they are isotonic
10 Facilitated Diffusion Some molecules, such as Glucose, move across the cell membrane through protein channelsFacilitated diffusion= is when a protein in the cell membrane helps a molecule move across it
12 Active TransportActive transport is when a cell uses energy to “pump” molecules across the membrane against the concentration gradientMoving molecules from a low concentration to a high concentrationRequires energy!!
13 Active Transport Molecule to be carried Section 7-3 Energy Molecule being carriedEnergySection 7-3Active TransportTo concept map
14 EndocytosisEndocytosis = is the process of taking material into the cell by means of infoldings, or pockets of the cell membraneEndo = In
15 Endocytosis – two types Phagocytosis: extensions of cytoplasm surround a particle and package it within a food vacuolePinocytosis: tiny pockets form around the cell membrane, fill with fluid, and pinch off to form vacuoles
16 Exocytosisexocytosis: the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell.Exo = Out