University:
Winston-Salem Forsyth County Schools
Course:
AP Biology
Academic year:

2011
Views:

152

Pages:

2
Author:

michmashd9x

Name: _____________________________________ Key Terms: Plasma membrane Homeostasis pH Osmosis Diffusion Active transport Passive transport Semi-permeable membrane Testing Your Knowledge: 1. What is the function of the plasma membrane? The plasma membrane controls what goes into the cell and what come out of the cell. 2. The plasma membrane is semi-permeable, what does this mean? Semi-permeable or selectively permeable means that only certain molecules can pass through the membrane. 3. The fluid mosaic model is used to represent the plasma membrane, why? The plasma membrane is not solid. Phospholipids in the bilayer move fluidly. 4. What is homeostasis? Homeostasis refers to an organism’s ability to maintain its internal environment. 5. How do humans maintain homeostasis? When a human exercises and begins to get hot, the body sweats in an effort to cool itself. 6. Describe osmosis. Osmosis is the movement of water molecules through a selectively permeable membrane from an area of high to low concentration. Name: _____________________________________ 7. Describe diffusion. Diffusion is the movement of molecules across a membrane from an area of high to low concentration. 8. What is the difference between active and passive transport? Active transport requires the help of proteins or pumps to move materials against a concentration gradient. 9. What is the osmotic pressure? How can changes be predicted? Osmotic pressure depends on concentrations of solute and refers to the movement of water across a membrane. Water moves from an area of high concentration to an area of low concentration (osmosis and diffusion).