B3 Biological Molecules

Question 1

What chemical elements make up carbohydrates?

Answer 1

C, H, O

Question 2

What chemical elements make up fats?

Answer 2

C, H, O

Question 3

What chemical elements make up proteins?

Answer 3

C, H, O, N, S

Question 4

____ molecules are made up from ____ molecules

Answer 4

Large, samller

Question 5

What is starch and glycogen (carbs) made up of?

Answer 5

Glucose

Question 6

What are proteins made up of?

Answer 6

Amino acids

Question 7

What are fats & oils made up of?

Answer 7

Fatty acids and glycerol

Question 8

Describe the food test for glucose (reducing sugars)

Answer 8

Benedict’s solution + food sample + heat –> blue - not present, green - low concentration, orange/yellow - positive

Question 9

Describe the food test for starch.

Answer 9

Iodine solution + food sample –> yellow - not present, blue/black - present

Question 10

Describe the food test for fats & oils.

Answer 10

1. Ethanol + food –> leave to dissolve
2. Add water
   Colourless - not present, white emulsion - present

Question 11

Describe the food test for proteins.

Answer 11

Biuret solution + food sample –> blue - not present, lilac/purple - present

Question 12

What is Biuret reagent made up of?

Answer 12

Mixture of sodium hydroxide and copper sulfate