1.5 Lipids Flashcards
What characteristics to all lipids share?
-contain hydrogen carbon and oxygen
-the proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates
-insoluble in water
-soluble in organic solvents such as alcohols and acetone
What are the main groups of lipids called?
triglycerides and phospholipids
How do lipids provide a good source of energy?
when oxidises they provide more than twice the energy as the same mass of carbohydrate
How do lipids provide a goof source of waterproofing?
-insoluble in water
-produce an oily secretion from the sebaceous glands in the skin
How do lipids provide a good source of insulation?
-slow. conductors of heat
-act as electrical insulators in the myelin sheath around nerve cells
How do lipids provide a good source of protection?
fat is stored around delicate organs, such as the kidney
What does a triglyceride contain?
3 fatty acids
What is a saturated fatty acid?
a fatty acid that has no carbon carbon double bonds
What is an Unsaturated fatty acid?
had carbon carbon double bonds
State the characteristics of triglycerides?
-excellent source of energy
-good storage molecules
-large
-non-polar
What makes a phospholipid different from a lipid
one of the fatty acid molecules is replaced by a phosphate molecule
Do phospholipids repel or attract water?
repel (hydrophobic)
State the test for lipids?
add ethanol
What would a positive test for lipids look like?
a cloudy white emulsion
