M&R 1.1 - The Membrane Bilayer Flashcards
What are the functions of the bilayer? (5)
- Continuous and selective permeable barrier
- Control chemical environment inside
- Communication
- Recognition
- Signal generation in response to stimuli
What is the dehydrated composition of the membrane?
- 40% Lipid
- 60% Protein
- 1-10% Carbohydrate
How does the hydrated composition of the membrane differ from the dehydrated composition?
Hydrated is 20% water
What is the significance of water in the Bilayer?
- Bonds to Bilayer with hydrogen bonds
- Facilitates hydrophilic interactions
Which 3 lipids are involved in the membrane?
- Phospholipids
- Glycolipids
- Cholesterol
Describe the head of a phospholipid molecule
- Hydrophilic
- Polar
- Negative
Describe the fatty acid chains of a phospholipid molecule
- Hydrophobic
- Uncharged
- Non-polar
- Cis double bond causes a kink
What is the advantage of phospholipids in the bilayer?
Increases the fluidity therefore allowing it to be ever-changing
How do Glycolipids differ from phospholipids?
The phosphocholine moiety is replaced with a sugar group
What is a Glycolipid with a sugar monomer called?
Cerebroside
What is a Glycolipid with an oligosaccharide chain called?
Ganglioside
What is the advantage of the similarity between phospholipids and Glycolipids?
Creates a constant environment for membrane proteins
Describe the head group of a cholesterol molecule
- Polar
- Hydrophilic
- Hydroxyl
Describe the tail group of a cholesterol molecule
- Aliphatic
- Non-polar
Describe the conjugated ring structure of a cholesterol molecule
- Planar
- Single bonds that are rigid
