Biology food tests Flashcards
(15 cards)
Why do we do food tests?
To test for concentration and presence of carbohydrase, proteins and lipids.
What colour is Benedict’s reagent?
Blue liquid
What colour does Benedict’s reagent turn when sugars are present?
Green, yellow, orange, red
What does Benedict’s test identify?
Sugars
How do we test for sugars after applying Benedict’s reagent?
Heat the food up
What colour is Iodine solution?
Brown
What colour will Iodine turn if starch is present?
Black
What does the iodine test identify?
Starch
What happens when starch is present in food?
Iodine will bind and turn black
What colour is Biuret reagent?
Blue
What colour will Biuret reagent turn if proteins are present?
Purple shade
What does the Biuret test identify?
Proteins
How do we test for osmosis?
Potato test
Name the steps of the potato test
Cut potato into identical pieces, measure mass of potatoes and record, put into tub with different concentrations of sugar or salt into water, leave the potatoes for a while, dry off potato slices and weigh them again, calculate the mass gained or lost during the experiment
Why do we use potatoes for osmosis tests?
Potato cells are semi permeable allowing water to be passed but not solutes
