Biological molecules

Question 1

Sources of carbohydrates

Answer 1

Bread, rice, pasta, potato, yam, noodles

Question 2

Function of carbohydrates

Answer 2

Provides energy for cell activities

Question 3

Benedicts test

Answer 3

Add 2 cm3 benedicts solution to 2cm3 of food sample. Place test tube in boiling water bath for 2-3 minutes.

Question 4

Results for Benedict’s test

Answer 4

Blue (no reducing sugar)
Orange (traces of reducing sugar)
Yellow (moderate amount of reducing sugar)
Red (Large amount of reducing sugar)

Question 5

Iodine test

Answer 5

Add few drops of iodine in potassium iodide to food sample

Question 6

Results for iodine test

Answer 6

Iodine solution turns from blue to blue black in the presence

Question 7

Digestion of carbohydrates

Answer 7

starch (cellulose and glycogen) to Maltose (sucrose and lactose) to glucose (fructose and galactose)

Question 8

Sources of protein

Answer 8

Tofu, Beef, Chicken, Pork, Soybean, fish

Question 9

Functions of protein

Answer 9

Suppose cell growth, repair worn out muscles

Question 10

Biuret’s test

Answer 10

Add 2cm3 of liquid food sample to 2cm3 of biuret solution. Shake well and stand for 5 minutes.

Question 11

Results for biuret’s test

Answer 11

Violet indicates presence of protein, blue indicates absence of protein

Question 12

Digestion of protein

Answer 12

Protein to polypeptide to amino acids

Question 13

Sources of Fat

Answer 13

Butter, cheese and avocado

Question 14

Results for ethanol emulsion test

Answer 14

White emulsion produced

Question 14

Functions of fat

Answer 14

Source of energy

Question 15

Ethanol emulsion test

Answer 15

Add 2cm3 of ethanol to a drop of liquid food sample, shake throughly. Add 2cm3 of water and shake.

Question 16

Digestion of fats

Answer 16

3 fatty acids and glycerol