Lipids Flashcards
Describe the key structural features of fatty acids.
Hydrophobic hydrocarbon chain with a terminal carboxy group
Explain the functions of fatty acids.
Major source of energy in body, form structural components of cells and organelles, cell signalling (prostaglandins, leukotrienes, steroids)
Describe the key structural features of mono-, di- and tri-acylglycerides.
Glycerol and corresponding number of fatty acid chains.
Explain the functions of mono-, di- and tri-acylglycerides.
Triacylglycerides: main form of energy storage in body, stored in adipose tissue, DAG’s are potent intracellular signallers, mobilize Ca++, monacylglycerol is a breakdown product of TAG in fat digestion
Distinguish between the classifications of lipids.
1)fatty acids and derivatives (prostaglandins and leukotrienes)
2) lipids containing glycerol (MAG/DAG/TAG) and phospholipids
3) lipids not containing glycerol (steroids and sphingolipids)
4) lipoproteins and lipopolysaccharides
Explain the functions of lipids.
Energy, cell and organelle structure, cellular signalling
Describe the key structural features of lipids (phospholipids, sphingolipids, sterols, lipoproteins and terpenes).
- Phospholipids: phosphate group in hydrophilic head
- Sphingolipids: sphingosine + FA + R group
- Sterols: 4 ring structure
- Steroid: fused 4 ring s with hydroxy or keto group on C3
- Lipoproteins: spherical, transport lipids in plasma
- Terpenes: made of isoprene units
Discuss disorders of fatty acid oxidation with particular reference to those involving medium chain length fatty acids (e.g. medium chain acyl CoA dehydrogenase deficiency - MCAD).
MCAD involved in mitochondrial FA B-oxidation, deficiency (autosomal recessive) causing intolerance to fasting, hypoglycaemia, impaired ketogenesis, hypoglycaemic coma.
What are the essential fatty acids?
- Linoleic acid (omega 6 FA)
- a linoleic acid (omega 3 FA)
- Deficiencies are rare but can cause scaly dermatitis and visual & neurological abnormalities
