Lipids Flashcards
What do lipids contain?
Carbon, hydrogen and oxygen.
What is smaller in carbohydrates then in lipids?
The proportion of oxygen to carbon and hydrogen.
What are lipids in water?
Insoluble.
What are lipids soluble in?
Organic solvents such as alcohols and acetone.
What are the main groups of lipids?
Triglycerides and phospholipids.
What are triglycerides?
Fats and oils.
What are the roles of lipids?
Source of energy, waterproofing, insulation, protection and in cell membranes.
Why are lipids used for waterproofing?
They are insoluble in water.
What is an example of lipids being used for waterproofing?
Plants and insects have waxy, lipid cuticles that conserve water.
Why are lipids used as insulation?
Fats are slow conductors of heat.
What are fats at room temperature?
Solid.
What are oils at room temperature?
Liquids.
Why are triglycerides called triglycerides?
They have three fatty acids combined with a glycerol.
What bond does each fatty acid form with glycerol?
Ester bond.
In what reaction does an ester bond form?
Condensation reaction.
What does hydrolysis of a triglyceride produce?
Glycerol and three fatty acids.
What is the worded formula for a triglyceride?
Glycerol+3 fatty acids—>triglyceride+3 waters.
What happens if the glycerol molecule in all triglycerides are the same?
The differences in the properties of different fats and oils come from variations in the fatty acids.
How many different fatty acids are there?
Over 70.
What do all fatty acids have?
A carboxyl group with a hydrocarbon chain attached.
When is a fatty acid described as saturated?
When the fatty acids hydrocarbon chain has no carbon-carbon double bonds.
Why do we call fatty acids with no carbon-carbon double bonds saturated?
All carbon atoms are linked to the maximum possible number of hydrogen atoms.
What do we call a fatty acid with a single bond between carbons in the hydrocarbon chain?
Mono-unsaturated.
What do we call a fatty acid with more then one double bond between carbons in the hydrocarbon chain?
Polyunsaturated.
Why are triglycerides an excellent source of energy?
They have a high ratio of energy storing carbon-hydrogen bonds to carbon atoms.
What is a benefit of triglycerides having a low mass to energy ratio?
They make good storage molecules as much energy can be stored in a small volume.
What kind of molecules are triglycerides?
Large, non-polar molecules.
What is a result of triglycerides being large, non-polar molecules that are insoluble?
Their storage doesn’t affect osmosis in cells or the water potential of them.
What is a benefit of triglycerides having a high ratio of hydrogen to oxygen atoms?
They release water when oxidised and therefore provide an important source of water.
How are phospholipids different from lipids?
One of the fatty acids is replaced by a phosphate molecule.
What are fatty acids in water?
Hydrophobic.
What are phosphate molecules in water?
Hydrophilic.
What is a phospholipid made from?
A hydrophilic head and a hydrophobic tail.
What are molecules with two ends (poles) called?
Polar.
What do phospholipids form in aqueous solutions?
A bilayer within cell surface membranes.
Where are the hydrophilic phosphate heads held?
At the surface of the cell surface membrane.
What can form from a phospholipid and carbohydrate?
A glycolipid.
What are glycolipids important in?
Cell recognition.
