Testing For Biological Molecules Flashcards
(28 cards)
What’s something we do at the start of each testing?
Grind the food we are testing we a small amount of distilled water.
What do we grind food in?
A mortar and pestle.
What do we do once the grinder mixture is a paste?
Add more distilled water and stir.
What do we do after we mix the food paste and distilled water?
We filter the mixture to remove solid food particles.
Why do we filter solid food particles?
As they could make the test results difficult to see.
What is the filtrate?
The food solution that passes through the filter.
How much of the food solutions do we place in the test tube?
3cm^3
What solution do we add to test for starch?
A solution containing iodine and potassium iodide.
How much iodine solution do we add to test for starch?
1cm^3
What colour does the solution turn if starch is present?
A blue-black colour.
What colour would the solution be if starch isn’t present?
Remain orange.
What solution is first added to test for proteins?
Dilute sodium hydroxide solution.
What solution is added second to test for proteins?
Dilute copper (||) sulfate solution.
What do we do after we add in solutions?
Mix.
What colour does the solution turn if protein is present?
Purple or lilac.
What colour will the solution be if protein isn’t present?
Remain blue.
What is biuret solution?
A premixed solution of sodium hydroxide and copper (||) sulfate.
What does the test for protein actually detect?
Peptide bonds.
What are peptide bonds found in?
Proteins.
What are peptide bonds not in?
Amino acids.
In what test must the food solution not be filtered?
Test for lipids.
Why is the lipid solution not filtered?
As the lipids stick to the filter paper.
What do we do to the lipid food solution instead of filtering it?
Leave it to allow the food particles to settle.
What and how much do we add to test for lipids?
3cm^3 of ethanol and 3cm^3 of water.
