lipids

Question 1

Describe how to do the emulsion test for lipids and how a positive result would be identified.

Answer 1

mix with / add , ethanol / alcohol , and water ;
(goes) cloudy ;
(emulsion test)

Question 2

How might the lipid content of mycoprotein differ from food that comes from animals?

Answer 2

less (overall , lipid / fat) ;
less / no , saturated (fat / lipid / fatty acids) ;
more unsaturated (fat / lipid / fatty acids) ;

Question 3

Identify two differences and two similarities in the structures of triglycerides and phospholipids

Answer 3

triglyceride phospholipid
difference 3 fatty acids 2 fatty acids ;
difference 3 ester bonds 2 ester bonds ;
difference absence of phosphate presence of phosphate ;
similarity (contain) glycerol ;
similarity (contain) fatty acids ;
similarity (contain) ester bonds ;
similarity (contain elements) C,H and O ;

Question 4

Uses of lipids;

Answer 4

• steroid hormones
• source of cholesterol
• insulation of neurones
• membranes
• protection of organs
• thermal insulation
• stores energy/ biological fuel

Question 5

Describe saturated fatty acids

Answer 5

• maximum hydrogen bonds
• solid at room temperature
• single carbon bonds

Question 6

Describe unsaturated fatty acids

Answer 6

• double bond carbon
• not fully saturated with hydrogen
• liquid at room temperature
• double bond causes a kink in structure

Question 7

Describe a triglyceride

Answer 7

• glycerol + 3 fatty acids
• 3 ester bonds
• created through condensation

Question 8

Describe phospholipids (5)

Answer 8

• two fatty acids tail
• phosphate head
• amphipathic; hydrophilic head, hydrophobic tail
• Contains glycerol
• ester bonds

Question 9

Describe cholesterol

Answer 9

• amphipathic; OH group polar head phospholipid

Hydrocarbon end hydrophobic

Question 10

What are the three types of lipids?

Answer 10

• triglycerides
• phospholipids
• steroids

Question 11

Describe a fatty acid

Answer 11

• carboxylic acid

- carboxyl group (COOH) and hydrocarbon chain