Food and Biological Molecules

Question 1

Testing for starch

Answer 1

• Add iodine
• If starch is present, it will turn from orange-brown to blue-black

Question 2

Testing for glucose (sugar)

Answer 2

• Add benedicts and heat it (90)
• If glucose (sugar) is present, it will turn from blue to red

Question 3

Testing for protein

Answer 3

• add sodium hydroxide and a few drops of copper sulphate (biuret reagent)
• If protein is present, it will turn from blue to lilac

Question 4

Testing for fat

Answer 4

• Crush with ethanol and then add water
• If it is present, a white emulsion will form

Question 5

Examples and use of Protein

Answer 5

Meat, Fish, Eggs, Beans

Growth and repair

Question 6

Examples and use of Carbohydrates

Answer 6

Potatoes, Bread, Pasta

To release energy (through
respiration)

Question 7

Examples and use of Lipids

Answer 7

Butter, oily fish

To provide energy, be an
energy store, to protect
organs and for heat
insulation (typically for small intestine :) )

Question 8

Examples and uses of Vitamins

Answer 8

Fresh fruit and vegetables

Vitamin C – healthy skin

Vitamin A – good vision

Vitamin D – for calcium
absorption

Question 9

Examples and uses of Fibre

Answer 9

Cereal, Brown Pasta and
rice, Bread, Vegetables

Keeps food moving through
the gut

Question 10

Deficiency of Protein

Answer 10

Kwashiorkor

Question 11

Vitamin C defficiency

Answer 11

Scurvy

Question 12

Vitamin D defficiency

Answer 12

Rickets