Chemical tests Flashcards Preview

AQA A Level Biology COPY > Chemical tests > Flashcards

Flashcards in Chemical tests Deck (9)
Loading flashcards...
1
Q

What does Benedict’s Test test for?

A

Reducing and non-reducing sugars

2
Q

What does the emulsion test test for?

A

Lipids

3
Q

What does the Biuret Test test for?

A

Peptide bonds (proteins)

4
Q

How do you test for starch?

A

Add iodine solution. If starch is present, the solution will turn from orange red to blue black

5
Q

Which test would you carry out to test for proteins?

A

The Biuret test.

6
Q

How would you carry out a test to show the presence of proteins?

A

Crush/liquify the what you’re testing. Add an equal amount of biuret reagent. If proteins are present, it will turn from blue to lilac/purple

7
Q

How would you carry out a test to show the presence of reducing sugars?

A

Add copper sulfate (CuSO4) and heat in a water bath for 5 mins. If reducing sugars are present, a brick red precipitate will form. (Green–>violet–>orange–>red)

8
Q

How would you carry out a test to show the presence of non reducing sugars?

A

Carry out a Bendict’s test. If there is no colour change, take a new sample and add HCl to it. Heat it in a water bath for 5 mins, then add NaHCO3. Then redo Benedict’s test.

9
Q

How would you carry out a test to show the presence of lipids?

A

Add ethanol, shake, then add water gently on the side. If lipids are present,a cloudy layer will form on the top