Protein molecules play key roles in living organisms and are digested in the digestive system.
Name the four main chemical elements present in all protein molecules.
Protein and amino acids are related substances. Complete the table by inserting a tick (✓\checkmark✓) if the property applies or a cross (×\times×) if it does not.
| Substance | Is a polymer | Contains nitrogen | Broken down by protease | Absorbed into the blood in the small intestine | Synthesised at ribosomes |
|---|---|---|---|---|---|
| protein | |||||
| amino acid |
Describe how you could test a sample of food for the presence of protein.
Give two safety precautions you would take when carrying out the test.
21 exam-style questions on Edexcel IGCSE Biology Biological molecules. Each one has a worked solution and a mark scheme showing where the marks go.