Lipids

Question 1

Compare and contrast triglycerides to phospholipids.

Answer 1

Triglycerides and phospholipids have similar structures as they are both made up of glycerol connected to fatty acid molecules through ester bonds.
However, triglycerides contain 3 fatty acid ‘tails’, whereas phospholipids only have 2.
Phospholipids also possess a phosphate group which is absent in triglycerides.

Question 2

what bond is involved in the synthesis of a phospholipid or triglyceride from glycerol and fatty acids?

Answer 2

Ester bond

Question 3

What type of reaction is the synthesis of ester bonds?

Answer 3

condensation reaction

Question 4

What type of reaction is the breaking apart of a triglyceride or phospholipid?

Answer 4

Hydrolysis reaction

Question 5

What is the function of triglycerides?

Answer 5

-Used as an energy source
-Inside cells, triglycerides group together into lipid droplets where the hydrophobic tails face inwards and the hydrophobic heads face outwards.
-These insoluble droplets make good energy storage molecules since they do not affect the osmotic potential of the cell.

Question 6

What is the function of phospholipids?

Answer 6

• they are the main component of cell membranes
  -form a phospholipid bilayer with the hydrophobic tails facing each other and the hydrophilic heads facing outwards, forming a barrier to prevent any polar molecules from entering or leaving the cell

Question 7

What is the function of cholesterol?

Answer 7

-helps strengthen the cell membrane
-cholesterol pushes the hydrophobic tails of phospholipids closer together, making the membrane more rigid.