Plasma Membrane Structure and Function

Membrane Functions Protection Communication Recognition Selectively allow substances in Respond to environment The last two can be combined and reworded as maintaining homeostasis

How does the cell Membrane maintain homeostasis? Separating the outside environment from the inside of the cell Regulating what goes in and out of the cell Cell membrane is Selectively Permeable Lets some molecules pass through while keeping other molecules out Think about it! What goes in? What leaves?

How molecules enter and leave the cell is related to cell membrane structure Look at all of the parts. They all play a specific role.

Cell Membrane structure Phospholipid bilayer hydrophilic heads-like water (polar) hydrophobic tails-don’t like water (nonpolar) Phospholipids are in motion!

embedded in the cell membrane Cholesterol Keeps the membrane fluid at low tempertures Keeps the phospholipids from moving too fast at high temperatures Transport Proteins Passage way for food, water and ions Receptors Proteins Receives chemical messages from outside the cell and sends them inside Marker Proteins Name tags that lets the cell know that the cell belongs to you Anchor Proteins Keeps other proteins in the membrane from moving