Lipids & Membranes Flashcards
What is an advantage of a fluid membrane?
Proteins can communicate much faster with each other
What is a property of carbohydrate chains for cell-cell signalling?
They are hydrophobic
What membrane is the only one to contain carbohydrates?
Plasma membrane
How much of cholesterol is made in the diet?
10%
Give 5 examples of proteins in membranes
- Structural
- Receptors
- Ion Channels
- Transporters
- Enzymes
What are the 3 types of membrane protein and give info on each?
Integral (intrinsic) - embedded in the lipid membrane and span the entire membrane. they form either alpha helices or beta strands.
Anchored proteins which are covalently bound fatty acids. They allow fluidity of the membrane.
Peripheral (extrinsic) proteins which are attached to membrane surface by ionic interactions with integral proteins or with the polar head of phospholipids.
Lipids are — in water, — in fat and organic solvents
Insoluble, soluble
What are examples of a polar head on phospholipids?
choline, ethanolamine, inositol
Why are phospholipids amphiphatic?
They have a hydrophilic head and hydrophobic tails.
What bond holds a fatty acid chain to a glycerol molecule?
An ester bond
In a fatty acid, what does (x:y) stand for?
x = number of carbons in chain y = number of double bonds
Draw the cholesterol molecule
Look up
What does the polar head of the cholesterol bind to?
The head of the phospholipid
What is meant by the lipid bilayer being asymmetrical?
The two halves have a different lipid composition.
What is the definition of fluidity?
The ease at which lipid molecules move about in the plane of the bilayer (regulates movement of proteins, signalling and exocytosis)