B4 biological molecules

Question 1

chemical elements that make up carbohydrates

Answer 1

• carbon
• hydrogen
• oxygen

Question 2

chemical elements that make up fats

Answer 2

• carbon
• hydrogen
• oxygen

Question 3

chemical elements that make up protein

Answer 3

• carbon
• hydrogen
• oxygen
• nitrogen

Question 4

what large molecules can be formed from glucose

Answer 4

• starch
• cellulose
• glycogen

Question 5

what is protein made from

Answer 5

amino acids

Question 6

what is fat made from

Answer 6

fatty acids and glycerol

Question 7

how to test for starch

Answer 7

iodine solution test
- add drops of iodine to solution/food
- red-brown –> blue black

Question 8

how to test for reducing sugars

Answer 8

benedict’s solution test
- add equal solution to be tested + benedict’s solution
- shake and heat gently
- blue –> green –> yellow –> orange –> brick red

Question 9

how to test for proteins

Answer 9

biuret test
- add biuret solution and shake for 15s
- blue –> violet

Question 10

how to test for fats and oils

Answer 10

ethanol emulsion test
- add ethanol and shake gently
- filter and discard residue
- cloudy white suspension