Lipids 1 Flashcards
Structure of membranes?
Sheet like, two molecules thick, form closed boundaries between different compartments
What are membrane lipids?
Small molecules that have both hydrophilic and hydrophobic moieties. They spontaneously form lipid bilayers that are a barrier to the flow of polar molecules
What do membranes consist of?
Lipids and proteins, also carbohydrates
What regulates the functions of membranes?
Specific proteins
How are proteins and lipids held together?
By non covalent interactions which act cooperatively
Symmetry of membranes?
Asymmetric- two faces of biological membranes differ
Fluidity of membranes?
Very fluid as there is a rapid diffusion of lipids in the plane of the membrane- although they do not readily rotate across
Polarity of membrane?
Most cell membranes are electrically polarised, eg the inside is typically negative
Four major roles of fatty acids?
- Are building blocks of phospholipids and glycolipids
- Proteins are modified by the covalent attachment of fatty acid
- Are fuel molecules
- Derivatives of fatty acids serve as hormones and intracellular messengers
What are fatty acids stored as?
Triacylglycerols (uncharged esters of fatty acids with glycerol)
What are saturated fatty acids?
Only single bonds in the fatty acid
What are unsaturated fatty acid?
At least one double bone on the fatty acid
Stereochemistry of double bond in unsaturated fatty acid?
Cis
What is oleate?
A monosaturated fatty acid : 18:1 cis-9
Do fatty acids vary in chain length and degree of unsaturation?
Yes
16 carbon fatty acid?
Palmitate; CH2(CH2)14COO-