1. Processes for maintaining homeostasis Osmosis, diffusion, active transport, passive transport Warm-up Questions: What is homeostasis? Which organelle is responsible for letting things in and out of the cell?

2. Passive transport Passive transport is a process that does not require the cell to use any extra energy to preform. Osmosis is the diffusion of water through a semi-permeable membrane, typically with a concentration gradient. Passive diffusion is the transport of molecules from an area of high concentration to an area of low concentration. Facilitated diffusion uses carrier proteins to facilitate particle transfer. Passive Diffusion Facilitated Diffusion

3. Isotonic, hypertonic, hypotonic. When the concentration of particle is unbalanced between the inside and outside of the cell osmosis will occur until the levels are isotonic, or balanced. Hypertonic is when there are more particles on the outside of the cell rather than on the inside. Hypotonic is when the concentration of particles is greater inside the call rather than outside.

4. Active transport Carrier proteins are used to move large molecules (too big to diffuse through), ions(these cannot get pass the hydrophobic tails of the lipid bilayer), or to move in the opposite direction of the concentration gradient. It is also used to move materials out of the cell. This requires energy to be used in the form of ATP. Membrane video. The sodium potassium pump is used to move sodium and potassium ions across the cell membrane.