Exchange And Transport Flashcards
What type of Phosphate heads line the external surface?
Hydrophilic
What lipid tails line internal surfaces?
Hydrophobic
what two things are embedded in the cell membrane?
Proteins and Glycoproteins.
what is allowed to diffuse in and out of the diffusion barrier?
Small non- polar molecules.
What are phospholipids made from?
Two fatty acid chain ‘tails’ which attach to one phosphate group ‘head’
what is the phosphate group?
Polar and hydrophilic.
What is the fatty acid chains?
Non- polar and hydrophobic.
what happens to phospholipids when in water?
When exposed to water phospholipids form one of two structure: a micelle or a bilayer.
Phospholipid bilayer is described as?
Partially permeable.
Permeability depends on?
The membrane composition.
who and when was the fluid mosaic model created?
Proposed by Singer and Nicholson in 1973.
Mosaic means?
Phospholipid bilayer is randomly populated with proteins.
Fluid means?
Phospholipid and proteins have free movement within the membrane.
what does a channel protein do?
Allows ions to diffuse into and out of the cell.
What does channel proteins do?
upon activation the active site can change shape to carry specific molecules across the membrane e.g. glucose.
