Why is the cell membrane so important?

Cell Membrane Basics Also known as the plasma membrane Semi-permeable-only some material can get in or out 3. Has a phospholipid bilayer inside cell outside cell

Semi-Permeable Membrane Controls what gets in or out Needs to allow some materials — but not all — to pass through the membrane lipid inside cell outside cell salt waste sugar aa H2O

Semi-Permeable Membrane What gets in easily? Lipids Water Why? 1. Channels are made out protein; “likes” both water and lipids

Semi-Permeable Membrane Movement Movement Types: Passive Transport- No energy required Active Transport- Energy required (ATP)

Passive (No Energy) Transport Diffusion – molecules move from a high to low concentration Osmosis- water moves from a high to low concentration Wants to create homeostasis! High Low

Water balance is important! Osmosis Water balance is important! Hydrated Dehydrated “Drown”

Hypotonic Solution: Higher concentration of fresh water outside of the cell. Cell swells and bursts. Hypotonic Solution: Equal amount of fresh water inside and outside of cell. Hypertonic Solution: Lower concentration of fresh water outside of the cell. Cell shrinks.

Two Types of Diffusion Facilitated Diffusion: Simple Diffusion: Osmosis and Diffusion Facilitated Diffusion: Uses protein pump due to size of molecules

VS Active Transport Molecules move from low to high Requires energy (ATP) VS

Active Transport Endocytosis: Engulfs/Brings in molecules Exocytosis: Allows molecules and waste to exit a cell