Biochemistry Tests Flashcards
0
Q
Test for reducing sugars
A
Heat with Benedict’s solution (CuSO4)
Sugar reduces CuSO4
Blue solution to orange-red precipitate
1
Q
Testing for starch
A
Add a solution of iodine (in KI).
Changes colour from yellow-brown to blue-black
2
Q
Non-reducing sugars
A
Boil with HCl (hydrolysis the sugar to monosaccharides)
Cool and neutralise with NaHCO3 or Na2CO3
Carry out Benedict’s test
Blue solution to orange-red precipitate
3
Q
Testing for lipids
A
Mix with ethanol, dissolves lipids
Pour into water in test tube
Cloudy, white emulsion forms near top, lipid comes out of solution, disperses as tiny droplets
4
Q
Test for proteins
A
Add Biuret reagent (NaOH and CuSO4)
Reacts with peptide bonds
Colour change from pale blue to lilac
