tests

Question 1

how to test for protein

Answer 1

-add small amount of sample to test tube
-add Biuret solution
- shake / mix
- if protein present = goes purple/ lilac
-if protein not present = remains blue

Question 2

Test for starch

Answer 2

-add iodine solution to food sample
-if starch is present : goes blue-black
-if no starch : remains orange -brown

Question 3

Test for reducing sugars

Answer 3

• add Benedict’s solution to sample
  -heat in water bath for 5 mins
  -if sugar present: solution turns green/ yellow/ orange / brick red
  -if sugar not present it remains blue

Question 4

Test for lipids

Answer 4

-add ethanol and shake
-pour into cold water
-if lipids present : cloudy white emulsion form
-if lipids not present: solution remains clear

Question 5

experiment to show how different concentrations of sodium chloride solution affect appearance of plant cells

Answer 5

immerse onion skin (onion epidermis)

same volume of solutions

at least 2 different concentrations of salt solution

leave cells for 2 minutes

observe/ photograph under microscope