Lipids

What is a saturated fatty acid?

A fatty acid with no double bonds between carbon atoms in its chain

What is an unsaturated fatty acid?

A fatty acid with one or more double bonds between carbon atoms in its chain

What is a monounsaturated fatty acid?

A fatty acid with one double bond between carbon atoms in its chain

What is a polyunsaturated fatty acid?

A fatty acid with more than one double bond between carbon atoms in its chain

Are animal fats saturated or unsaturated?

Saturated

Are oils saturated or unsaturated?

Unsaturated

Give two properties of fatty acids.

• High ratio of C-H bonds to carbons

• Hydrophobic

Give 2 functions of triglycerides.

• Waterproofing

• Energy storage molecule

What is the structure of phospholipids?

A glycerol molecule, 2 fatty acids, a phosphate group

What makes up the phosphate group in a phospholipid?

Phosphorus, 3 oxygens, OH group attached

What are three properties of phospholipids?

• Half polar, half non-polar

• Insoluble in water

• Soluble in alcohol

Which region of a phospholipid is polar, and how do you know?

The head- phosphate group is hydrophilic, so attracts water

Which region of a phospholipid is non-polar, and how do you know?

The tail- fatty acids are hydrophobic, so repel water

How do phospholipids orient themselves when placed in water?

With the hydrophilic phosphate heads facing towards the water and the hydrophobic fatty acid tails facing away from the water

What 3 structures can phospholipids form in water?

Bilayer, monolayer, micelle

Why are triglycerides and phospholipids both soluble in alcohol?

Alcohols have both a polar and a non-polar region

What test can you use to test for the presence of lipids in a sample?

The emulsion test

What are the steps, and positive result, of the emulsion test?

• Add ethanol and shake

• Add cold water and shake

• A milky white emulsion will form

What are the 2 lipids you need to know?

Triglycerides and phospholipids

What is the structure of a fatty acid?

A hydrocarbon chain attached to a carboxyl group

What is the common abbreviation for a fatty acid?

RCOOH

What is the structure of a triglyceride?

3 fatty acids and a glycerol molecule

What is the name of the bond between the fatty acids and the glycerol?

Ester bond

Ester bonds are formed during which type of reaction?

A condensation reaction

What word can be used to describe phospholipids as being half hydrophobic, half hydrophilic?

Amphipathic