Cell Transport Passive and Active Transport About Cell
Cell Transport Passive and Active Transport
About Cell Membranes 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 (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
Structure of the Cell Membrane Outside of cell Proteins Lipid Bilayer Transport Protein Animations of membrane Go to structure Section: Carbohydrate chains Phospholipids Inside of cell (cytoplasm)
Types of Cell Transport 1. Passive Transport cell doesn’t use energy HIGH low concentrations 2. Active Transport cell does use energy LOW high concentrations
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
Concentration Gradient Concentration gradient- the difference in concentration of solutes or particles in different places
1. Diffusion Simple Diffusion Animation 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 http: //bio. winona. edu/berg/Free. htm
2. 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
3. Osmosis animation Osmosis is ONLY the diffusion of water through a selectively permeable membrane Water moves from high to low concentrations
Solute/Solvent/Solution 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?
Hypotonic Solution Hypotonic: A solution that has a lot of water and that water moves INSIDE the cell making it swell • Osmosis Animations for isotonic, hypertonic, and hypotonic solutions
• Hypertonic Solution 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 shrinks Osmosis Animations for isotonic, hypertonic, and hypotonic solutions
• Isotonic Solution 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! Osmosis Animations for isotonic, hypertonic, and hypotonic solutions
What type of solution are these cells in? A B C Hypertonic Isotonic Hypotonic
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). 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 animations
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