Biological Molecules

Question 1

What is the element and monomers that make up carbohydrates

Answer 1

Monomer- glucose
Elements- carbon, hydrogen, oxygen

Question 2

How are carbohydrates stored in different organisms

Answer 2

Plants cell wall- cellulose
Plants- starch
Animals- glycogen

Question 3

What is the element and monomers that make up lipids

Answer 3

Monomer- 1x glycerol, 3x fatty acids
Element- carbon, hydrogen, oxygen

Question 4

What is the element and monomers that make up proteins

Answer 4

Monomer- amino acids
Elements- carbon, hydrogen, oxygen, nitrogen

Question 5

Testing for starch

Answer 5

1 prepare food sample appropriately (if solid crush with a pestle and mortar and add 5cm^3 or water) and place in test tube
2 add 5cm^3 of iodine solution
3 observe color change if positive orange brown to blue black

Question 6

Testing for reducing sugars

Answer 6

1 prepare food sample appropriately (if solid crush with a pestle and mortar and add 5cm^3 or water) and place in test tube
2 add 5cm^3 of Benedict’s solution
3 prepare a water bath set at 75C and observe the test tubes for 5 mins
4 observe color change if positive blue to green, orange, brown or brick red depending on the percentage of glucose

Question 7

Testing for protein

Answer 7

1 prepare food sample appropriately (if solid crush with a pestle and mortar and add 5cm^3 or water) and place in test tube
2 add 5cm^3 of biuret solution
3 observe color change if positive pale blue to purple

Question 8

Testing for lipids

Answer 8

1 prepare food sample appropriately (if solid crush with a pestle and mortar and add 5cm^3 or water) and place in test tube
2 add 5cm^3 of distilled water
3 add 5cm^3 of ethanol
4 observe color change if positive cloudy emulsion forms