Lipids and Membranes Flashcards
Lipid
Insoluble in water but soluble in fat and organic solvents
Biological function of lipids
Energy store
Precursors for vitamins
Steroid hormones
Bile acids
Membrane structure
Triglycerides
AKA triacyclglycerols
3 fatty acids and glycerol
Where are triglycerides stored?
In adipose tissue
What are fatty acids?
Long chain aliphatic carboxylic acids
Polyunsaturated fatty acid
Contains more than one double bond
What does delta symbol show?
The position of the double bond relative to the carboxylate group
What are phospholipids made of?
Glycerol
2 fatty acids
Phosphate containing head group
What is the phosphatidyl group?
Phosphate glycerol and fatty acid component
Common head groups
Choline
Serine
Ethanolamine
Inositol
What are glycolipids made of?
Glycerol
2 fatty acids
Head group containing sugar
Structure of steroids
Multi ring hydrophobic region
Hydrophilic region
Composition of plasma membrane
H-L
Cholestrol
Phosphatidylcholines
Phosphatidylethanolamine
Sphingophospholipid
Carbohydrate
Composition of outer mitochondrial membrane
45% Phosphatidylcholines
Others
Composition of inner mitochondrial membrane
50% Phosphatidylcholines
Others
Composition of nuclear membrane
55% Phosphatidylcholines
Others
10% Cholesterol
PE
Phosphatidylethanolamine
PC
Phosphatidylcholines
What happens if there are more short chain fatty acids?
Fewer Van der Waals
Greater fluidity
What happens due to kinks in unsaturated fatty acids?
Fewer Van der Waals
Greater fluidity
What happens if there is greater cholesterol in the membrane?
Lower fluidity
Types of membrane proteins
Structural
Receptors
Ion channels
Transporters
Enzymes
How to remove peripheral proteins?
High salt, urea
Detergent
Phospholipases
How to remove anchored proteins?
Detergent
Phospholipases
How to remove integral proteins?
Detergent
TSD
Tay Sachs Disease
Autosomal recessive disease
Causes accumulation of GM2 gangliosides in neurone lysosomes
Defect in enzyme that breaks down GM2 gangliosides
Trademark symptom of TSD
Macular cherry red spot during ophthalmology observation
Breakdown of gangliosides
GM1 - GM2 - GM3 - Glc Cer - Cer - Sphingosine
Amphipathic
Polar head group and non polar fatty acid tail
What are anchored proteins?
Proteins that are covalently linked to a fatty acid chain or to surface glycolipid
What are lipid rafts?
Ordered membrane microdomains linked to cell signalling that have high levels of cholesterol
