Membrane & Diffusion notes
- 1. KEY CONCEPT The cell membrane is a barrierKEY CONCEPT The cell membrane is a barrier that separates a cell from the externalthat separates a cell from the external environment.environment.
- 2. Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers.
- 3. Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers. • The cell membrane has two major functions.The cell membrane has two major functions. cell membrane
- 4. Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers. • The cell membrane has two major functions.The cell membrane has two major functions. o forms a boundary between inside and outside of the cell cell membrane outside cell inside cell
- 5. Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers. • The cell membrane has two major functions.The cell membrane has two major functions. – forms a boundary between inside and outside of the cell – controls passage of materials cell membrane outside cell inside cell
- 6. Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers.
- 7. cell membrane Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers. • The cell membrane is made of a phospholipidThe cell membrane is made of a phospholipid bilayer.bilayer.
- 8. cell membrane Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers. • The cell membrane is made of a phospholipid bilayer.The cell membrane is made of a phospholipid bilayer. • There are other molecules embedded in the membraneThere are other molecules embedded in the membrane.. protein cholesterol proteincarbohydrate chain protein channel
- 9. cell membrane Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers. • The cell membrane is made of a phospholipid bilayer.The cell membrane is made of a phospholipid bilayer. • There are other molecules embedded in the membrane.There are other molecules embedded in the membrane. • TheThe fluid mosaic modelfluid mosaic model describes the membrane.describes the membrane. protein cholesterol proteincarbohydrate chain protein channel
- 10. Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers. • The cell membrane is selectively permeable.The cell membrane is selectively permeable. Some molecules can cross the membrane while others cannot.
- 11. Cell membranes are composed of twoCell membranes are composed of two phospholipid layers.phospholipid layers. • The cell membrane is selectively permeable.The cell membrane is selectively permeable. Some molecules can cross the membrane while others cannot.
- 12. KEY CONCEPT Materials move across membranes because of concentration differences. 3.4 Diffusion and Osmosis3.4 Diffusion and Osmosis Concentration Gradient: when there is a difference in concentration between two areas
- 13. Passive transport does not require energy input from a cell. • Molecules can move across the cell membrane through passive transport. • There are two types of passive transport. • osmosis • diffusion 3.4 Diffusion and Osmosis3.4 Diffusion and Osmosis
- 14. Diffusion and osmosis are types of passive transport. • Molecules diffuse down a concentration gradient. • How would you define DIFFUSION?! 3.4 Diffusion and Osmosis3.4 Diffusion and Osmosis
- 15. Diffusion and osmosis are types of passive transport. • Osmosis is the diffusion of water molecules across a semipermeable membrane. 3.4 Diffusion and Osmosis3.4 Diffusion and Osmosis
- 16. Diffusion and osmosis are types of passive transport. • There are three types of solutions. • isotonic 3.4 Diffusion and Osmosis3.4 Diffusion and Osmosis • hypotonic • hypertonic
- 17. Some molecules can only diffuse through transport proteins. • Some molecules cannot easily diffuse across the cell membrane. • Facilitated diffusion is diffusion through transport proteins. 3.4 Diffusion and Osmosis3.4 Diffusion and Osmosis