4.1 Plasma Membrane Structure and Function The plasma membrane regulates the passage of molecules into and out of the cell.The membrane contains lipids and proteins. Each protein has a specific function.
1. Why is the term "fluid-mosaic" used to describe the plasma membrane? Answer2. What is the glycocalyx? Answer
4.2 The Permeability of the Plasma Membrane Some substances, particularly small, noncharged molecules, pass freely across the plasma membrane.The plasma membrane is differentially permeable. Therefore, some ions and polar molecules need assistance to cross the membrane.
3. What is meant by "differentially permeable?" Answer4. How does passive transport differ from active transport? Answer
4.3 Diffusion and Osmosis Molecules spontaneously diffuse (move from an area of higher concentration to an area of lower concentration), and some can diffuse across a plasma membrane.Water diffuses across the plasma membrane, and this can affect cell size and shape.
5. Why does oxygen diffuse from the lungs into the blood and not in the opposite direction? Answer6. If a cell is placed into a hypotonic solution, in what direction will there be movement of water? Answer
4.5 Exocytosis and Endocytosis Vesicle formation takes other substances into the cell, and vesicle fusion with the plasma membrane discharges substances from the cell.
9. Pinocytosis differs from phagocytosis in what way? Answer
Fluid-Mosaic Model of Membrane Structure 1 (50.0K)