Food and its Importance

Question 1

Why humans need to consume food?

Answer 1

Repair worn out tissues
• Maintain a healthy body
• Grow new cells and tissues
• Gain energy for daily activities

Question 2

What are the substances?

Answer 2

1. Proteins
2. Carbohydrates
3. Fats
4. Fibre
5. Vitamins
6. Mineral salts
7. Water

Question 3

What are the nutrients?

Answer 3

1. Proteins
2. Carbohydrates
3. Fats
4. Vitamins
5. Mineral salts

Question 4

What are the food tests?

Answer 4

Food test Nutrients that produces a positive result
Biuret test : Protein
Benedict test : Sugar (Glucose) Carbohydrates
Iodine test : Starch
Grease spot test : Fats
Ethanol Emulsion test : Fats

Question 5

What is The Biuret test used for?

Answer 5

Proteins

Question 6

What are the steps? [ Biuret ]

Answer 6

1. Prepare the food sample solution in a test tube.
2. Add one drop of Biuret solution into the food sample.
3. Shake the test tube for a few seconds.
4. Repeat the process with a few more drops of Biuret solution.

Question 7

What are the colours?

Answer 7

• If protein is present:
- Colour changes from
blue to purple
• If protein is absent:
- Colour remains blue

Question 8

What is the Benedicts tst used for?

Answer 8

Benedict test is used to detect the presence of glucose.

Question 9

What are the steps? [ Benedicts ]

Answer 9

1. Prepare the food sample solution in a test tube.
2. Add equal volume of Benedict solution into the test tube.
3. Place the test tube in a hot water bath for a few minutes.
4. Take out the test tube when the colour stopped changing.

Question 10

Can Benedicts solution detect sucrose?

Answer 10

Benedict solution can only

detect glucose.

Question 11

What are the colours? [Benedicts]

Answer 11

• If glucose is present:
- Colour changes from blue to:
▪ greenish-yellow (low glucose level) /
▪ orange (moderate glucose level) /
▪ brick-red (high glucose level)
• If glucose is absent:
- Colour remains blue