Biology chapter 7

What is meant by the fluid mosaic model of membrane structure?

a tapestry of several types of molecules (phospholipids, cholesterols, and proteins) that are constantly moving. This movement helps the cell membrane maintain its role as a barrier between the inside and outside of the cell environments.

What are the types and examples of facilitated diffusion?

carrier proteins and channel proteins. Ex. Ex. : Aquaporin channel

What are the components of membranes?

lipids, proteins, and carbohydrates

What affects the rate of simple diffusion versus facilitated diffusion?

low solute concentration

What are the types and examples of active transport?

pumps and coupled transport. Ex. sodium potassium pump. Ex. Electrochemical gradient

What influences membrane fluidity?

temperature, cholesterol, and the kind of fatty acids in the phospholipids that form the cell membrane.

What explains the orientation of phospholipids within the bilayer?

The head (polar region) of each phospholipid molecule is oriented towards the exterior of the bilayer. The tail (nonpolar region) of each phospholipid molecule is oriented towards the interior of the bilayer. This orientation is due to the hydrophobic effect.