Biological Molecules

Question 1

Carbohydrates elements present

Answer 1

Carbon, hydrogen and oxygen

Question 2

Simple molecules carbs

Answer 2

Monsaccharids (simple sugars) - building blocks for complex carbs

Eg) glucose, galactose and fructose

Question 3

Simple carbs 2

Answer 3

Dissacharides - 2 joined monosaccharides

Eg) sucrose, maltose, lactose

Question 4

Complex carbs

Answer 4

Polysaccharides - rich in vitamins, minerals and fibre

Eg) glycogen (animals), starch (plants), chitin

Question 5

Use of carbohydrates

Answer 5

Provide energy

Constant level of glucose in the blood must be obtained

Question 6

Test for starch

Answer 6

Iodine test:

1) add 3-5 drops of iodine solution to a food sample on spotting tile
2) brown - blue/black mean starch is present

Question 7

Test for glucose:

Answer 7

Benedicts test for glucose

1) place 2ml (10 drops) of Benedicts solution to 5-6 drops of test solution
2) test tube in water bath at 90 degrees for 5 mins
3) original colour - brick red

Question 8

Proteins elements present

Answer 8

Hydrogen, carbon, oxygen, nitrogen and some sulfur

Question 9

Monomers of proteins

Answer 9

Amino acids

Question 10

Polymers of proteins

Answer 10

Polypeptides

Question 11

What do npolypeptide chains make up

Answer 11

Proteins

Question 12

Use of proteins

Answer 12

Cellular support

Cell signalling

Question 13

Test for proteins

Answer 13

Biuret solution:

1) add 5 drops of biuret solution to aqueous food sample
2) record colour change: blue - violet

Question 14

Lipids elements present

Answer 14

Carbon, hydrogen and oxygen

Question 15

Monomers of lipids

Answer 15

Fatty acids (x3) + glycerol

Triglycerides

Insoluble in water

Question 16

Uses of lipids

Answer 16

Energy storage

Forming membranes

Question 17

Test for lipids

Answer 17

Emulsion test:

1) add 5ml of ethanol to food sample
2) shake test tube
3) add shaken solution to water
4) clear to cloudy