PH1123 - Lipids Flashcards
lipid structural function? (2)
- plasma membrane (phospholipids)
- intracellular organelles
lipid energy function? (2)
- energy stores
- insulation (white adipose tissue and brown adipose tissue (thermogenesis))
lipid carrier function?
- absorption and transport of fat soluble vitamins (A, D, E, K)
lipid messenger function?
- cell signalling
examples of simple lipids? (2)
- fats; esters of fatty acids with glycerol (oils are fats in the liquid state
- waxes; esters of fatty acids with higher molecular weight than monohydric alcohols
examples of complex lipids? (2)
- phosphoipids
- glycolipids
examples of precursor and derived lipids? (3)
- fatty acids
- glycerol
- steroids
- hormones
what are triglycerides and their main function?
- they are esters of glycerol and fatty acids
- main storage forms of fatty acids
what are the differences between fats and oils? (2)
- fats have all available bonding sites taken up by H (saturated)
- oils have fewer Hs on account of double bonds (unsaturated)
what are the two molecules which the backbone of phospholipids are built? (2)
- (phospho)glycerides
- sphingosine
what is the structure of a phospholipid? (4)
- one unit of glycerol
- two units of fatty acids
- phosphate group
- N2 containing group
what is the polarity of a phospholipid like? (2)
- N2 end tends to attract a H+ and becomes positively charges; polar and water soluble
- fatty acid tails are non-polar and insoluble
what is the structure of sphingolipids?
- backbone is sphingosine not glycerol
where are sphingolipids mainly found?
- prominent on plasma membrane of cells
what are phophatidylinositols? (2)
- precursor molecule for phosphatidylinositol 4,5-bisphosphate (PIP2)
- cleaved to form DAG and IP3
what does DAG stand for?
- diacylglycerol
what does IP3 stand for?
- inositol triphosphate
what are DAG and IP3 examples of?
important secondary messengers
why are steroids classified as lipids?
- due to their solubility (they are hydrophobic)
what is the structure of steroids?
- four interlocking rings of C atoms with side groups attached to rings
what is cholesterol a precursor molecule for? (4)
- bile acids
- sex hormones
- adrenocortical hormones
- vitamin D
what is the structure of glycolipids?
- sugar attached to fatty acids
what are eicosanoids derived from?
derived from eicosa (-C20) polyenoic fatty acids
example of eicosanoids and function? (2)
- prostaglandins
- they act as local hormones and cause muscle contraction and inflammation
