3 What have I learned about health and lifestyle?

Summary: Tags: science oxford-science student-book-7 biology Created: 2026-05-19 Last Updated: 2026-05-19

In this chapter, you have:

• learned about the parts of a balanced diet, and how much of each part you should eat to stay healthy
• tested a range of foods to identify which nutrients they contain
• studied the main organs in the digestive system
• learned about the role that bacteria and enzymes play in digestion
• understood the effects of harmful substances on the body.

Journey through health and lifestyle What do I already know? - A healthy diet

• Good hygiene
• Breathing
• Movement of joints and muscles This chapter - 3.1 Nutrients
• 3.2 Digestive system
• 3.3 Food tests
• 3.4 Unhealthy diet
• 3.5 Bacteria and enzymes in digestion
• 3.6 Harmful substances What comes next? - Respiration
• Digestive system and enzymes

Figure 1

1. To stay healthy, you must eat a balanced diet. Match the nutrients to their function in the body. Nutrient carbohydrates lipids proteins minerals Function used for growth and repair needed in small amounts to keep you healthy provide Energy provide a store of energy and are used to insulate the body (4 marks)
2. Figure 1 shows the digestive system. Figure 1 Name structure X. (1 mark)State what happens in structure Y. (1 mark)Identify which letter represents the structure that stores faeces until it leaves the body. (1 mark)State what happens in digestion. (2 marks)
3. Describe the role of two parts of a balanced diet. (4 marks)
4. A student wants to do a food test to find out which nutrients are in crisps. They start by making a solution of the crisps. Name the piece of equipment the student should use to break the crisps into small pieces. (1 mark)Suggest two safety precautions the student should take before doing a food test. (2 marks)Describe how the student should test the food solution for protein. (3 marks)
5. Drugs that are not given to us by a doctor can harm our body. Describe the meaning of a medicinal drug. Give one example. (2 marks)State how a drug causes an effect on the body. (1 mark)Explain the difference between a stimulant and a depressant. (2 marks)
6. Enzymes are special proteins that play an important role in digestion. Describe the role of enzymes in digestion. (1 mark)Explain why enzymes are called Catalysts. (2 marks)Compare how carbohydrates and proteins are digested. (4 marks)
7. Explain some health issues caused by an unhealthy diet. (6 marks)