4. Biological Molecules

Question 1

List the chemical element that make up carbohydrate, protein and fats

Answer 1

Carbohydrates - carbon, hydrogen and oxygen
Fats-carbon, hydrogen and oxygen

Protein - Carbon, hydrogen, oxygennitrogen and sulphur

Question 2

What all can glucose link up

Answer 2

• Glycogen, starts or cellulose

Question 3

What are proteins and fats made from

Answer 3

Amino acid
Fatty acids and glycerol

Question 4

Describe the test for carbohydrates.

Answer 4

Test for starch
Iodine solution
P-blue/black_- —- N- orange-brown

Fest for reducing sugar heat)
Benedict solution
P- green yellow than brick red
N-blue

Question 5

Describe the tests for fats and oil

Answer 5

Ethanol emulsion test
Shake food with ethanol, pour into a tube containing water
P - milky appearance with droplets formed

Question 6

Describe the test for proteins

Answer 6

Biuret reagent
Positive-purple
Negative-blue

Question 7

Describe dcpip test

Answer 7

‘test for presence of vitamin C
Negative - blue/purple
Positive - colourless

Question 8

3 main constituents of a DNA nucleotide

Answer 8

Base
Deoxyribrase sugar
Phosphate ‘

Question 9

Describe the structure of a DNA molecule

Answer 9

• 2 strands of nucleotides are coiled together to form a double helix
• each strand contains chemicals called bases
• every pair has bonds between them to hold them together
• there is a complementary base pairing where A pairs with and C pairs with G