Nutrients

Question 1

What are the function of Water in humans?

Answer 1

1. Solvent for chemical reaction
2. Essential components of cells, tissue, fluids, digestive juices and blood.
3. Transport dissolved substances around the body
4. Controls body temperature

Question 2

What are the function of Water in plants?

Answer 2

1. Essential for photosynthesis
2. Keeps plant turgid→Helps keep the plant upright
3. Needed for transport of mineral salts up the xylem.
4. Needed for transport of sucrose and amino acids in the phloem

Question 3

What is a condensation reaction?

Answer 3

A condensation reaction is a chemical reaction in which two simple molecules are joined together to form a larger molecule with the removal of one molecule of water.

Question 4

What is hydrolysis?

Answer 4

Hydrolysis is a chemical reaction in which a water molecule is needed to break up a complex molecule into smaller molecules.

Question 5

What are the 3 monosaccharides?

Answer 5

Glucose, Fructose, Galactose

Question 6

What are the 3 disaccharides?

Answer 6

Maltose, Sucrose, Lactose

Question 7

What are the 3 polysaccharides?

Answer 7

Starch, Glycogen, Cellulose

Question 8

Which sugar isn’t a reducing sugar?

Answer 8

Sucrose

Question 9

What are carbohydrates made up of? What is the ratio?

Answer 9

Carbohydrates are made up of elements carbon, hydrogen and oxygen. They are in the ratio of C:H:O is 1:2:1

Question 10

What are the functions of carbohydrates?

Answer 10

1. Provide energy for cell activities
2. Form protection layer(Cellulose used for cell wall)
3. Conversion into other organic compounds(eg. Amino acids and fats)
4. Form nucleic acid(eg. DNA)
5. Synthesize lubricants
6. Synthesize nectar in flowers

Question 11

How to test for reducing sugars?(Benedict’s test)

Answer 11

1. Add 2ml of benedict’s solution to 2ml of food sample in a test tube.
2. Shake the mixture
3. Heat the contents in a boiling water bath for 2-3 minutes.

Question 12

What does the different colours of the benedict’s test tell?

Answer 12

Remains blue→no reducing sugar
Turns green→trace of reducing sugar
Turns orange→moderate amount of reducing sugar
Turns red→large amount of reducing sugar

Question 13

What are fats made up of?

Answer 13

Fats are organic molecules made up of elements like carbon, hydrogen and oxygen.

Question 14

What are the properties of a saturated fat?

Answer 14

Fatty acid chain is straight and it is solid at room temperature.

Question 15

What are the properties of unsaturated fat?

Answer 15

Fatty acid chain is wavy and it is liquid at room temperature.

Question 16

What are the functions of fats?

Answer 16

1. Source and store of energy
2. Insulating material to prevent excessive heat loss
3. Solvent for fat soluble vitamins and hormones
4. Component of cell membranes
5. Reduce water loss from skin

Question 17

How to test for fats?(ethanol emulsion test)

Answer 17

1. Add 2ml of ethanol to 2ml of food sample in a test tube.
2. Shake the contents of the tube vigorously.
3. Add 3ml of water into the test tube and shake the mixture

Question 18

What are proteins made up of?

Answer 18

Proteins are organic molecules made up of the elements carbon, hydrogen, oxygen and nitrogen.

Question 19

What are the function of proteins?

Answer 19

1.Synthesis of new protoplasm for growth and repair of
worn-out cells
2.Synthesis of enzymes and some hormones
3.Synthesis of antibodies

Question 20

How to Test for protein(Biuret test)

Answer 20

1. Add 2ml of sodium hydroxide solution to 2ml of food sample into a test tube.
2. Shake the mixture thoroughly
3. Add 1% copper(ll) sulfate solution drop by drop, shaking the mixture after each drop