The Cell Membrane Write

Cell Membrane The membrane of the cell has many different names. You may hear it called: The phospholipid bilayer The semi-permeable membrane Fluid Mosaic Model Plasma membrane Listen

Cell Membrane Properties Semi-permeable Some things can move in and out of the cell membrane freely, while others cannot. Write

Phospholipid Bilayers The major component of Cell membranes are phospholipids that combine to make a phospholipid bilayer. Phospholipid – a type of lipid Bi – two Layer – a sheet of material Two layers of phospholipids Listen

Phospholipid Bilayer This is a phospholipid It has a phosphate head and two tails (fatty acid chains) Head = Hydrophilic (Loves water) Tails = Hydrophobic (Fears Water) Draw and Label

Phospholipid Bilayer This is a phospholipid Bilayer There are two layers of phospholipids Draw and Label

Phospholipid Bilayer Formation When put into water, phospholipids will arrange themselves so that their heads are in the water. This allows the tails to group together and stay away from the water. Listen

Phospholipid Bilayer The Bilayer creates a sphere that is known as a liposome. Our cell membranes are a large liposome. Listen

Things in the Phospholipid Bilayer Phospholipids Cholesterol Open Channel Proteins Gated Channel Proteins Protein/Sugar Markers Write

Phospholipids Structure: Lipids Function: Makes up majority of the Cell membrane Write

Cholesterol Structure: Lipids Function: Stabilizes the cell membrane Write

Open Channel Proteins Structure: Proteins Function: Allow molecules that cannot pass through the phospholipid bilayer into the cell Write

Open Channel Protein Example Example: Aquaporins Water is a polar molecule and cannot pass through the phospholipid bilayer due to the hydrophobic tails. Instead it moves in and out of the cells through a type of open channel protein called an aquaporin. Listen

Gated Channel Proteins Structure: Proteins Function: Allow molecules that cannot pass through the phospholipid bilayer to pass only if certain conditions are met Write

Gated Channel Protein Example Example: Insulin and Glucose Before Glucose can go through a gated protein channel, insulin must first signal the gated protein channel to open. Listen

Markers Structure: Proteins + Carbohydrate Chains Function: Tag and identify the cell. Important for immune system function. Write

Gated Channel Protein Example Example: Blood Types Blood Types are determined by the type of carbohydrate chains you have on your red blood cells. If you are Type O you have do not have A or B carbohydrate chains Your body will attack any cell that has A or B carbohydrate Chains If you are Type A you have A carbohydrate Chains Your body will attack any cells that have B carbohydrate chains If you are type B you have B carbohydrate chains Your body will attack any cells that have A carbohydrate chains If you are Type AB you have both A and B carbohydrate chains Your body will not attack A or B chains O A B AB =A =B Listen

Solutions Listen

Solutions A solution is made of at least two parts. The solvent and one or more solutes. Solvent: A liquid, usually water, that dissolves a solute Solute: Something that is dissolved by a liquid Listen

Solution Water Solvent Solute Solution Listen

Concentrations Concentration: how much solute is in the solution. Listen

Different Concentrations Low Concentration High Concentration Listen

Concentration Gradient:A change in concentration between two solutions. Equilibrium:the concentration of particles is equal on both sides of the semi- permeable membrane. Properties of Two Interacting Solutions Write

Concentration Gradients When two solutions with different concentrations are placed together a concentration gradient appears Solution with a low concentratio n Solution with a high concentratio n Concentration Gradient

Equilibrium When two solutions with different concentrations mix until their concentrations are the same then equilibrium has been met. Equal Concentrations Equilibrium

Comparing Solutions When we compare two solutions together we use three terms to describe the solutions. Hypertonic – a solution that has a higher concentration (amount of solute) Isotonic – a solution that has the same concentration (amount of solute) Hypotonic – a solution that has a lower concentration (amount of solute) Write

Isotonic A solution that has the same amount of solutes (concentration) when compared to another solution. 50% H2O 50% Solute 50% H2O 50% Solute Have the same concentration Isotonic

Hypotonic A solution that has a lower amount of solutes (concentration) when compared to another solution. 63% H2O 37% Solute 90% H2O 10% Solute Hypotonic Hypertonic

A solution that has a higher amount of solutes (concentration) when compared to another solution. 90% H2O 10% Solute 40% H2O 60% Solute Hypertonic Hypotonic