Biological Molecules

Benedict's solution test for the presence of

• reducing sugars, e.g. glucose

• proteins

• fats

• starch

Biuret solution test for the presence of

• reducing sugars, e.g. glucose

• proteins

• fats

• starch

A sample of egg albumen (protein) solution was tested using the biuret test. Which one shows the result of the test and the deduction which can be made?

• A

• B

• C

• D

What shows that a solution contains protein?

• A

• B

• C

• D

Which food substance would produce a brick red precipitate when boiled with Benedict’s solution?

• fat

• protein

• reducing sugar

• starch

A food containing fats is tested with ethanol emulsion test. what would be the positive result?

• remains clear

• cloudy white emulsion forms

A food substance is tested with three reagents.

Iodine solution remains brown.

The biuret test gives a purple colour.

The ethanol test gives an emulsion.

Which nutrient(s) does the food substance contain?

• A

• B

• C

• D

The diagram shows cells from a storage organ of a plant.

The structures X are stained blue-black by iodine solution. (Hint: Plants photosynthesise to produce glucose. Excess glucose is stored as _____?)

What does X contain?

• glycogen

• starch

• fat

• amino acids

What is the basic unit to build proteins?

• glucose

• amino acids

• fatty acids and glycerol

What is starch made from?

• glucose

• amino acids

• fatty acids and glycerol