Membranes Flashcards
What are membranes made out of?
Phospholipid bilayer
What are the properties of membranes?
Dynamic, flexible, insulating, selective permeability and act as binding sites for chemical recognition
What provides membranes with flexible properties?
Fatty acids
What provides membranes with insulating properties?
Hydrocarbon tails
What does dynamic mean?
Always being made and destroyed depending on the needs of the cell
What type of cell has the most protein?
Mitochondria
What are the 2 types of membrane proteins?
Integral and Peripheral
What is a peripheral membrane protein?
A protein that can be removed without disturbing the membrane. It is non-amphiphatic and its binding sites are on the IC side of the membrane. They can act as enzymes and are important for cell size and motility
What is an integral membrane protein?
A protein that can’t be removed without disturbing the membrane. It is amphipathic and its has the same orientation as the phospholipids and may span the membrane. They can act as channels, carriers, enzymes and receptors
Why do membrane proteins act as channels?
Allows ions to cross the membrane
Why do membrane proteins act as carriers?
Allows substances to be transported across the membrane
Why do membrane proteins act as enzymes?
To provide binding sites on the membrane surface
Why do membrane proteins act as receptors?
To provide recognition sites for chemicals
Where does diffusion occur?
Between compartments
What is the process of diffusion?
Movement form high -> low concentrations
What are the requirements for diffusion?
Permeable to the membrane, small, uncharged and lipophilic (hydrophobic)
What helps diffusion?
Large surface area, high permeability and high concentration gradient
What are protein channels?
They are trans-membranous IMPs that act as an aq route for the diffusion of ions