1. 5/4 Agenda
Homeostasis Review: osmosis, cell transport, signal transduction
Homework:
Study for AP Exam
Sleep/Relax/Eat Well
Do your best! You guys are awesome!

2. Homeostasis Overview
Homeostasis is the natural balance your body keeps
There are many ways your body maintains homeostasis
Cell signaling
Negative Feedback Mechanisms
Cell transport
Outside sources can cause a disruption in homeostasis
Exercise
Stress
Food
Infection
Extreme Temperature
All living organisms have methods for maintaining homeostasis

3. Osmosis Osmosis is the movement of water across a membrane
Water moves from a low concentration of solute to a high concentration of solute
Or moves from a high concentration of water to a low concentration of water
Plants prefer a hypotonic environment to allow pressure against the cell wall so the plant will stand up straight
If not, wilting will occur
Animal cells need an isotonic solution so our cells stay the same size

4. Osmosis

5. Osmosis and IVs
If normal red blood cells have a solute concentration of 0.095% NaCl, how would you design the IV solution?
Why?

6. Cell Transport Active transport= requires ATP
Moves against a concentration gradient
Low to high
Used to concentrate solution inside a cell
Endocytosis/Exocytosis is an example
Solute moves through membrane by pinching membrane and creating its own vesicle
Passive transport= does not require ATP
Moves from a high concentration of solute to a low concentration
Facilitated Diffusion- an example of passive transport, but used a membrane protein to guide solute through
Used for polar or charge particles, or larger particles

8. Body Temperature Regulation