Lipids Flashcards
Lipids form polymers and have an affinity for water. TRUE/FALSE?
False;
Lipids do not form polymers
They do not have an affinity for water
What type of functional group linkage holds a fatty acid to glycerol in a triacylglycerol?
An ester
Distinguish between a saturated and an unsaturated fatty acid in terms of chemical structure and overall shape.
A saturated fatty acid has single bonded carbon atoms which causes it to have a linear structure/shape.
Unsaturated fatty acids have double bonds between some of its carbon atoms which replace some hydrogen bonds. These double bonds create a ‘break’ or bend in the structure or shape of the subunit.
These rigid kinks in the fatty acid tails reduce the number of van der Waals attractions that can form along their lengths, causing oils to be liquids at room temperature.
Why do polyunsaturated fatty acids tend to be liquids (oils) at room temperature?
Polyunsaturated fats do not have as many hydrogen bonds in their chemical structure, and a such their weak intramolecular and intermolecular bonding makes them have a low melting point resulting in them being liquid at room temperature.
Draw a Kekule structure for palmitic acid, a 16-carbon fatty acid.
/\/\/\/\/\/\/\/ ^OH and H} at the end
(a) What is the shiny material on the surface of an apple?
(b) What is its purpose?
(c) How do the material’s properties suit its function?
a) Wax is the shiny material on the surface of an apple.
b) Its purpose is to preserve the apple; keep the skin looking fresh.
c) Wax is made up of hydrophobic properties that do not allow the apple to lose water and become dehydrated or dry up.
(a) How do steroids differ structurally from other lipids?
(b) List two biological functions of steroids.
a) Steroids are made up of hydrophobic molecules that are tightly packed and a four fused hydrocarbon ring structure whereas, other lipids have a wireframe or Kekule structure.
b) 1 - signal molecules 2- cholesterol is converted into vitamin D (healthy bones and teeth) and bile salts (digestion of fats)
(a) What process is used to produce vegetable oil margarine?
(b) Why do producers usually add yellow food colouring to margarine?
a) hydrogenation: adding hydrogen bonds to double bonds between carbons in the vegetable oils
b) Margarine has a naturally white colour that looks more like lard so to make it more appetizing producers added a yellow food colouring so that it resembled butter.
Why do physicians recommend that people not eat diets rich in cholesterol and/or saturated fats?
High cholesterol foods and saturated fats can clog the arteries and lead to atherosclerosis or other heart diseases. The fats and cholesterol form deposits of fats in the lining of blood vessels that can become hard and prevent blood flow which delays or obstructs the movement of oxygen and nutrients.
Why are fats more energetically dense than carbohydrates?
Fats are more reduced and therefore produce a lot of energy via oxidation.
