Cell Membrane Questions

1. Why is the cell membrane called a fluid mosaic model - because the membrane is fluid (oil consistency) and has a collection of components in it such as phospholipid, proteins and carbohydrate chains.

2. Structure and function of a glycoprotein Cell recognition proteins important for your immune system to recognize and destroy invaders

3. Why is the cell membrane the gatekeeper of the cell? The cell membrane (plasma membrane) is a barrier between the cell and its external environment It regulates the passage of molecules into and out of the cell

4. What substances are able to pass through the membrane? Not? Pass through: uncharged molecules and water Can’t pass through: macromolecules and ions - ions are transported into and out of the cell using proteins - macromolecules are transported into and out of the cell by exocytosis and endocytosis

5. Difference between active transport and passive transport Active transport requires energy and passive transport does not

6. Diffusion, facilitated diffusion and active transport

7.Why are large substances moved into and out of the cell by exocytosis and endocytosis…. THEY ARE TOO LARGE

10. Endocytosis and Exocytosis Endocytosis- decrease the circumference of the cell membrane Exocytosis- increases the circumference of the cell membrane

Property Simple Diffusion Facilitated Diffusion Active Transport Special Membrane proteins no yes Yes and No Highly selective No Yes (more specific than simple diffusion) Yes Require ATP Active or Passive transport passive active