Cell Transport Passive and Active Transport

1.All cells have a cell membrane a.Functions: o Controls what enters and exits the cell o Provides protection and support for the cell About Cell Membranes

About Cell Membranes (continued) 2. Structure of cell membrane a.The cell membrane is made of two layers of phospholipids called the lipid bilayer b.Proteins are also embedded in cell membrane Phospholipid Lipid Bilayer

About Cell Membranes (continued)  3. Cell membranes have pores (holes) in it a. the holes or pores makes the cell membrane Selectively permeable: or Allows some molecules in and keeps other molecules out Pores

Outside of cell Inside of cell (cytoplasm) Lipid Bilayer Proteins Transport Protein Phospholipids Carbohydrate chains Structure of the Cell Membrane Go to Section: Animations of membrane structure

1. Passive Transport  cell doesn’t use energy  HIGH  low concentrations 2. Active Transport  cell does use energy  LOW  high concentrations Types of Cell Transport

Passive Transport Characteristics  cell uses no energy  molecules move randomly  Molecules spread out from an area of high concentration to an area of low concentration.  (High  Low) 3 Different Types 1.Diffusion 2.Facilitated Diffusion 3.Osmosis

CC oncentration gradient- the difference in concentration of solutes or particles in different places Concentration Gradient

1. Diffusion 1.Diffusion: random movement of particles from an area of HIGH concentration to an area of low concentration.  Diffusion continues until all molecules are evenly spaced or have reached equilibrium Simple Diffusion AnimationSimple Diffusion Animation

Facilitated diffusion Facilitated diffusion happens when specific particles move through proteins found in the membrane  It is diffusion with the HELP of proteins in the membrane 2. Facilitated Diffusion

Osmosis water Osmosis is ONLY the diffusion of water through a selectively permeable membrane high to low  Water moves from high to low concentrations Osmosis Osmosis animation 3. Osmosis

 Solute – a SUBSTANCE dissolved in a fluid  Solvent – the FLUID part of a solution  Solution – a MIXTURE of two or more substances (a solute and solvent) Solute/Solvent/Solution

 This is sugar water.  What is the solute?  What is the solvent?  What is the whole mixture called? Solute/Solvent/Solution

 A glass of iced tea.  What is the solute?  What is the solvent?  What is the whole mixture called? Solute/Solvent/Solution

 Ex: Dr. Pepper  What is the solute(s)?  What is the solvent?  What is the whole mixture called? Solute/Solvent/Solution

HHHHypotonic: A solution that has a lot of water and that water moves INSIDE the cell making it swell Hypotonic Solution Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis

 Hypertonic: The solution has MORE solutes and a lower concentration of water  The water will move OUT of the cell making it shrink or crenate Hypertonic Solution Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis shrinks

 Isotonic: The concentration of solutes and water in solution and in the cell are EQUAL  Water moves equally in both directions and the cell remains same size! Isotonic Solution Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis

What type of solution are these cells in? A CB HypertonicIsotonicHypotonic

Overcoming Osmosis Contractile vacuoles – structure that will expel excess water from unicellular organisms that live in water. (like Paramecium!) Turgor pressure – water pressure in a plant cell when a plant is placed in a HYPOtonic solution. A loss of turgor pressure causes wilting (plasmolysis).Turgor pressure Paramecium (protist) removing excess water video

Active Transport Characteristics cell uses energy actively moves molecules to where they are needed Movement from an area of low concentration to an area of high concentration Goes AGAINST the concentration gradient 2 Types of Active Transport 1.Endocytosis 2.Exocytosis

Types of Active Transport 1. Endocytosis:  taking bulky material into a cell Uses energy Cell membrane fold in around food particle forms food vacuole & digests food This is how white blood cells eat bacteria!

Types of Active Transport 2. Exocytosis “leaving the cell”  Forces material out of cell in bulk membrane surrounding the material fuses with cell membrane Cell changes shape – requires energy EX: materials or wastes are released from cell Endocytosis & Exocytosis Endocytosis & Exocytosis animations

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