biology tests

Question 1

If asked to describe a practical investigation what do you do?

Answer 1

C - change - independent variable
O - organism being tested
R - repeats
M - measure - dependant variable
S - same - controlled variables

Question 2

Investigate food samples for the presence of starch

Answer 2

Starch is detected using iodine solution. This turns blue-black in the presence of starch.

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Question 3

Investigate food samples for the presence of protein

Answer 3

Proteins are detected using Biuret reagent. This turns a mauve or purple colour when mixed with protein.

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Question 4

Investigate food samples for the presence of glucose

Answer 4

Benedict’s solution gradually turns from blue to cloudy orange or brick red when heated with glucose.

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Question 5

Investigate food samples for the presence of fats/lipids

Answer 5

Ethanol is used a milky-white emulsion forms if the test substance contains lipids.

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