Digestion & Nutrition - Testing for protein and fat

Question 1

What is protein needed for?

Answer 1

Growth and repair

Question 2

Give one example of a protein rich food

Answer 2

Meat, cheese, fish

Question 3

What is fat needed for?

Answer 3

Insulation and energy

Question 4

Give two diseases linked with too much fat in the diet

Answer 4

Coronary heart disease (CHD), obesity

Question 5

Name one type of food that contains fat

Answer 5

Butter, cream, eggs, red meat

Question 6

What are the chemicals that can test for protein and fat?

Answer 6

Protein - Biuret reagent/Fat - ethanol

Question 7

What are Proteins?

Answer 7

Proteins are long chains of small
molecules called amino acids.
There are over 20 different kinds of amino acid.
Proteins are used by the body for growth and repair.

Question 8

Proteins are made of ?

Answer 8

Amino acids

Question 9

Proteins are not polymers because the amino acids in the chain are ?

Answer 9

Not the same

Question 10

Fats are made of ?

Answer 10

Fatty acids and glycerol

Question 11

Both protein and fats are ………………….. molecules ?

Answer 11

large

Question 12

Biuret solution will turn what colour in the presence of a protein ?

Answer 12

positive - purple/ lilac, negative - blue

Question 13

What is the colour change if protein is present?

Answer 13

Blue to purple/lilac

Question 14

If fat is present, the ethanol will turn a ………… colour when the water is added.

Answer 14

cloudy white

Question 15

What two chemicals are added to test for fat?

Answer 15

Water and ethanol

Question 16

What is a positive for an ethanol test

Answer 16

Clear and colourless to cloudy white

Question 17

how much water and/or ethanol is added to test for fat and in which order ?

Answer 17

2cm^3 of each, ethanol first