Biological Experiments

Question 1

In the test for starch, add what solution?

Answer 1

Iodine solution

Question 2

In a positive result for the test for starch…

Answer 2

Colour change: brown/yellow to blue/black

Question 3

For a test for reducing sugars (i.e monosaccharides, moltose and lactose), add what solution?

Answer 3

Benedict’s solution

Question 4

2 conditions for Benedict’s test.

Answer 4

i) Happens over a boiling water bath

ii) Use equal quantities of Benedict’s solution.

Question 5

For a positive result in the test for reducing sugars…

Answer 5

Colour change: Blue - green - yellow - orange - brick red.
Also precipitate forms at the bottom of the Benedict’s solution.

Question 6

For the test for protein, add which two solutions?

Answer 6

Sodium hydroxide and copper sulphate.

Question 7

For a positive result in the test for proteins / biuret test

Answer 7

Colour change: Blue to purple.

Question 8

The test for proteins is also known as…

Answer 8

The ‘biuret’ test. ‘Biuret’ is the name of the compound which gives the purple colour.