LIPIDS

Question 1

What are lipids made of?

Answer 1

They are made of carbon, hydrogen and oxygen atoms
There are 2 types - triglyceriedes and phospholipids

Question 2

What are the properties of triglycerides?

Answer 2

They are insoluble in water (hydrophobic)
They are soluble in organic solvents

Question 3

How do triglycerides form?

Answer 3

1 glycerol molecule forms with 3 fatty acids
Each fatty acid forms an ester bond with the glycerol as part of a condensation reaction.

Question 4

What are the 2 types of fatty acid?

Answer 4

If the fatty acid chain has no double carbon-carbon bonds, the fatty acid is saturated
If the fatty acid chain contains 1 double carbon-carbon bond, the fatty acid is mono-unsaturated
If the fatty acid contains multiple double carbon-carbon bonds, the fatty acid is poly-unsaturated

Question 5

How does saturation affect the lipid’s properties?

Answer 5

A saturated fatty acid is straight, meaning the atoms are more packed together, leading to a higher boiling point. Saturated fats are solid at room temperature

An unsaturated fatty acid causes a bend in the molecule, meaning the atoms aren’t packed together, leading to a lower boiling point. Unsaturated fats are liquid at room temperature.

Question 6

What are phospholipids?

Answer 6

They are similar to triglycerides, but in place of a third fatty acid, there is a phosphate group

Question 7

What are the properties of phospholipids?

Answer 7

While the fatty acid molecules are still hydrophobic, the phosphate group is hydrophilic, and is a ‘polar’ molecule.

Question 8

Where are lipids used?

Answer 8

Triglycerides are often stored around delicate molecules like kidneys
Thet help retain body heat in the body and act as insulators for the myelin sheath

Phospholipids form bi-layers within cell surface membranes, as the hydrophilic ‘head’ helps to hold at the membrane’s surface