Lipids Flashcards
What is the common and defining feature of lipids?
Insolubility in water
What are the main biological functions of lipids?
Energy storage
Structural components of cell membranes
Important signalling molecules
What are the 5 common classes of lipids in eukaryotic cells?
Fatty acids
Triacylglycerols
Phospholipids
Glycolipids
Sterols
What are fatty acids?
Carboxylic acids with hydrocarbon chains
What affects the physical properties of fatty acids?
Degree of unsaturated bonds
Are saturated or unsaturated fatty acids liquid at room temperature?
Saturated
What are fatty acdis named by?
Length of the hydrocarbon chain and number and position of any carbon-carbon double bonds
What are the essential fatty acids?
Polyunsaturated fatty acids that cannot be synthesised by humans and must be obtained from the diet e.g. omega-3 fatty acids and omega-6 fatty acids
What are triaclyglycerols?
Composed of three fatty acids covalently joined to glycerol through ester linkages
What do triacylglycerols do?
Provide stored energy and are stockpiled in adipocytes in humans
What is the main role of phospholipids and glycolipids?
Structure
What is the basic structure of phospholipids and glycolipids?
A backbone
At least one fatty acid
Something else
What are the two backbones possible for phospholipids and glycolipids?
Glycerol
Sphingosine
What are sphingolipids?
Phospholipids or glycolipids with a sphingosine backbone
What are sterols?
Precursors to other biomolecules such as steroid hormones and bile acids
What are sterols synthesised from?
Simple five carbon structures called isoprenes
What is the family of cholesterol inhibitors and give an example of one?
Statins
Rosuvastatin
What are the roles of cholesterol?
Production of sex hormones
Assists in bile production in liver
Building block for human tissues
Creating Vitamin D
What is Niemann-Pick Disease?
Lysosomal storage disease characterised by a sphingomyelin metabolism disorder
What causes Niemann-Pick Disease?
Rare autosomal recessive genetic defect in the gene encoding the enzyme sphingomyelinase resulting in a build up of sphingomyelin in the brain, spleen , liver and lungs
What is the outcome for those with Niemann-Pick Disease?
Develops in infancy and leads to mental impairment and eventually death
What is Tay-Sachs Disease?
Lysosomal storage disease due to mutations in the HEXA gene causing a build up of gangliosides in brain
What does the HEXA gene do?
Encodes the hexosaminidase A enzymes which catalyses the degradation of gangliosides
What is the outcome of a patient with Tay-Sachs Disease?
Progressive deterioration of nerve cells and of mental/physical capabilities that begins at ~6 months and usually results in death by age 4
