Cell Membrane and Diffusion Diffusion Demo 1 What

Cell Membrane and Diffusion

Diffusion Demo • 1) What color is the solution in the bag? • 2) What color is the solution in the beaker? • 3) What observations can you make after the bag has been sitting the solution after 30 minutes? • 4) Explain what has happened using the vocab brainstormed on the board. (remember the PEAR)

Diffusion notes • Remember molecules are always moving. • Diffusion: molecules moving from an area of high concentration to an area of low concentration • Equilibrium: concentrations equal out but molecules continue to move

Diffusion

Diffusion

Solutions-Fluid that contains dissolved solids • Solvent- Liquid portion of solution, dissolves solid • Solute- substance that is dissolved in a solvent

What Cell Membrane Let’s Diffuse • Yes • Water • Non charged Micromolecules (alcohol, oxygen, carbon dioxide) • No • Macromolecules • Don’t your cells need them? • Charged molecules

Osmosis • Diffusion of water across a membrane • One of the most important substances that crosses the membrane is water • Water is the solvent and glucose is the solute

Passive Transport • Passive transport (diffusion)uses no energy. • Tonicity- degree to which a solution’s concentration of solute versus water causes water to move into or out of a cell.

Types of Tonicity • Isotonic- solute conc. is equal on both sides of the membrane, no net gain or loss of water.

Types of Tonicity • Hypertonic- solution conc. of solute is higher than the conc. inside the cell. • Water conc. lower outside cell, water diffuses out of cell • Cell shrink

Types of Tonicity • Hypotonic – Solution conc. Of solute is lower than the conc. Inside the cell. • Water conc. Higher outside of cell, water diffuses in • Cell gets bigger

What type of tonicity? and explain the glucose and water levels both inside and outside of each cell?

Active Transport • Requires cells to expend energy to move molecules against the solute’s concentration gradient.

Facilitated Transport • Carrier Protein assists in movement of diffusion. • No energy required. • Increases rate of diffusion