Presentation on theme: "Cell Membrane Transport. Cell membrane transport There are 2 types of cell membrane transport: Passive Transport Substance move from High concentration."— Presentation transcript:
Cell membrane transport There are 2 types of cell membrane transport: Passive Transport Substance move from High concentration to low concentration -no energy required Active Transport Substance move from low concentration to high concentration -energy (ATP) required
Another perspective on passive and active transport
Passive Transport Diffusion The movement of particles from areas of high concentration to low concentration
Diffusion Factors that influence the rate of diffusion Temperature Pressure Electrical currents Molecular size
Equilibrium the concentrations of particles are the same on both sides of the membrane
Facilitated Diffusion Particles flow from high concentration to low concentration but this time they need the help of proteins to get through the cell membrane.
Osmosis The diffusion of water across a selectively permeable membrane Important in maintaining cell homeostasis Water flows to side of membrane where the water concentration is lower until equilibrium is reached
Osmosis Osmosis is controlled by the amount of solutes on either side of a membrane
Osmosis – Types of Solutions When dealing with osmosis, water can either move into the cell or out of it. The solute cannot move to equal out the concentration of solutions, so the water has to. We describe the solutions that cells are in as either hypotonic, isotonic, or hypertonic.
Isotonic Solution Isotonic solution – Concentration of solute is the same in the cell and the area around the cell. Water moves in and out at equal rates.
Hypotonic Solution Hypotonic Solution – Concentration of solute is lower in the solution than in the cell. Net movement of water INTO the cell.
Hypotonic solutions Since water moves into the cell the cell, animal cells can explode Cytolysis
Plant and animal cells in a hypotonic solution Turgor Pressure – central vacuole is full; pressure against the cell wall
Hypertonic Solution Hypertonic solution – concentration of solute is higher in the solution than in the cell. Net movement of water OUT of the cell.
Hypertonic solutions Since water moves out of the cell the cell will shrink
Plant and animals cells in a Hypertonic Solution Plasmolysis: shrinking of cytoplasm due to osmosis
Active Transport Molecules move from low concentration to high concentration Requires energy….why?
Active Transport Molecular Transport Protein Pumps Small molecules and ions carried across the cell membrane by proteins in the membrane that act like pumps (low high) Bulk Transport Endocytosis – in! Exocytosis – out!