A student tests three foods, X, Y and Z, for biological molecules.
The Table shows the results.
Table
| Food | Colour after heating with Benedict's reagent | Colour with iodine solution | Colour with biuret reagent |
|---|---|---|---|
| X | brick red | orange-brown | blue |
| Y | blue | blue-black | purple |
| Z | blue | orange-brown | blue |
Identify the food that contains starch.
Food Z contains lipids.
Describe a test the student could do to show that food Z contains lipids. Include the positive result.
The Benedict's test needs heating.
Describe how the student should heat the test tubes safely.
Food Y contains protein. Proteins are polymers.
Name the monomers that join together to make proteins.
113 exam-style questions on OCR GCSE Biology 1.3 Respiration, covering 1.3.1 Cellular respiration supplies ATP, 1.3.2 Aerobic and anaerobic respiration, 1.3.3 Sugars and carbohydrates, 1.3.4 Amino acids and proteins, and 1.3.5 Fatty acids and lipids. Each one has a worked solution and a mark scheme showing where the marks go.