Cell Membranes Flashcards
What is the structure of a cell membrane?
A bilayer of phospholipids which form micelles when in water
Hydrophilic heads point out and hydrophobic tails point inside.
What model are membranes described as?
The fluid mosaic model:
Membrane is a collection of different protein molecules that move around by diffusion.
How is the membrane affected by the saturation of fatty acids?
More saturate means lower melting point because membranes are more fluid
How does temperature affect the membrane?
More unsaturated means less affected by temperature drops
Cold- looses fluidity
Hot- gains fluidity
How does tail length affect fluidity?
Longer tail- decreased fluidity
Shorter tail- increased fluidity
What is the function of cholesterol in the cell membrane?
Fit between phospholipid bilayer and provides stability, reduces fluidity and prevents membrane from being too tightly packed and prevent polar molecules from leaking out of membrane
What re glycoproteins and glycolipids?
Proteins and lipids that have short carbohydrate chains attached to them.
How does cell signalling work?
A hormone (messenger molecule) is released in the blood stream
Hormone binds to receptor at the target cell
Receptor is complementary to hormone
Signal is converted from one method of transmission to another
Hormone triggers reactions within the cell
Final response occurs
