Topic: Physical Digestion
Lesson 1: Introduction to Physical Digestion and Human Teeth
| Section | Details |
|---|---|
| Objective | – Understand physical digestion as the breakdown of food into smaller pieces without chemical change. – Identify the types and structure of human teeth and their roles in physical digestion. |
| Activities | Starter (5 mins): Show a video or animation of chewing and ask students why chewing is important for digestion. Main (25 mins): 1. Define physical digestion as breaking food into smaller pieces without chemical changes. 2. Explain how physical digestion increases surface area for enzyme action. 3. Introduce types of human teeth and their functions: – Incisors: Cutting food. – Canines: Tearing food. – Premolars and Molars: Crushing and grinding food. 4. Show diagrams of human teeth and discuss their structure: – Enamel: Hard, protective layer. – Dentine: Supports enamel and contains tubules. – Pulp: Contains nerves and blood vessels. – Cement: Anchors teeth to the gums and bone. – Gums and Bone: Provide support. Plenary (10 mins): Students label a diagram of human teeth and match each type with its function. |
| Resources | Video or animation of chewing, diagrams of human teeth, labeling worksheets. |
| Time | 40 minutes |
| Homework | Draw and label a diagram of a human tooth and write a brief explanation of how each part supports physical digestion. |
| Assessment | Students correctly identify and label the types and structures of teeth and explain their functions during discussions and activities. |
| Past Paper Practice | IGCSE Biology 0610/21/M/J/19 Q2(a). |
Lesson 2: Role of Physical Digestion and Function of the Stomach
| Section | Details |
|---|---|
| Objective | – Describe the function of the stomach in physical digestion. – Understand the importance of physical digestion in increasing the surface area for enzyme action. |
| Activities | Starter (5 mins): Ask students to feel their stomach after eating and discuss what might be happening inside. Main (25 mins): 1. Explain how the stomach performs physical digestion: – Muscular Walls: Contract to churn food and mix it with gastric juices. – Mechanical Breakdown: Food is broken into smaller pieces. 2. Discuss the importance of physical digestion in increasing surface area for enzyme action during chemical digestion. 3. Relate the stomach’s physical digestion to enzyme activity in breaking down proteins. Plenary (10 mins): Students summarize the role of the stomach in physical digestion using bullet points. |
| Resources | Diagrams of the stomach, video of stomach churning food, summary worksheets. |
| Time | 40 minutes |
| Homework | Write a short paragraph explaining why physical digestion is essential before chemical digestion. |
| Assessment | Students correctly describe the role of the stomach and the importance of physical digestion during discussions and summaries. |
| Past Paper Practice | IGCSE Biology 0610/22/M/J/20 Q5(a). |
Lesson 3: Role of Bile in Digestion
| Section | Details |
|---|---|
| Objective | – Understand how bile emulsifies fats and oils to increase surface area for chemical digestion. – Outline the role of bile in the digestive process. |
| Activities | Starter (5 mins): Show an image of oil and water mixing poorly and ask students how this relates to fat digestion in the body. Main (25 mins): 1. Explain the production and storage of bile: – Produced by the liver. – Stored in the gall bladder and released into the small intestine. 2. Describe the role of bile in emulsifying fats: – Breaks fats into tiny droplets. – Increases surface area for lipase action. 3. Relate bile’s role to the efficient digestion of fats. Plenary (10 mins): Students create a diagram showing the emulsification process and explain it in pairs. |
| Resources | Images or videos of oil emulsification, diagrams of bile production and function, worksheets for diagram creation. |
| Time | 40 minutes |
| Homework | Write an explanation of how bile and enzymes like lipase work together to digest fats. |
| Assessment | Students correctly explain and diagram the role of bile in emulsifying fats during activities. |
| Past Paper Practice | IGCSE Biology 0610/31/O/N/19 Q3(a). |
Key Notes for Teachers:
- Use diagrams and videos to illustrate physical digestion and the role of the stomach and bile.
- Emphasize the link between physical digestion and its importance for chemical digestion.
- Provide hands-on activities, such as labeling and diagram creation, to reinforce learning.
Key Notes for Students:
- Physical digestion increases surface area for enzymes to act on food molecules.
- Human teeth, the stomach, and bile play critical roles in breaking down food physically.
- Bile emulsifies fats, making chemical digestion by lipase more efficient.
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