Year 8 - Science
Digestion and enzymes
Human digestive system
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit examines the human digestive system, including the roles of tissues, organs, enzymes, and beneficial bacteria. It also focuses on evaluating risks, interpreting data, identifying patterns, and suggesting improvements to enhance the reliability of investigations.
Lesson Summary
You will learn to describe the processes of mechanical and chemical digestion that break down food to release nutrients, including the role of enzymes.
Key Notes
- The differences between mechanical and chemical digestion and where they take place.
- Food is made up of carbohydrates, proteins and fats.
- Carbohydrates, proteins and fats in food are broken down by digestion into smaller molecules that can be absorbed.
- Enzymes are biological molecules that act as catalysts to speed up chemical digestion of carbohydrate, protein and fat.
- Enzymes digest carbohydrates into starch and sugars, proteins into amino acids, and fats into fatty acids and glycerol.
Vocabulary To Learn
- digestion: Digestion is the process of breaking down large food molecules into smaller molecules that can be absorbed into the blood.
- enzyme: An enzyme is a biological molecule that is a catalyst that speeds up the rate of a reaction.
- carbohydrate: A carbohydrate is a molecule made of carbon, hydrogen and oxygen, and provides energy.
- protein: A protein is a molecule made of amino acids, and is used for growth and repair.
- fat: A fat is a molecule that is stored and used for energy.
Common Mistakes To Avoid
- Food is absorbed without being digested; or "goodness" from food is what is absorbed.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
The differences between mechanical and chemical digestion and where they take place. Food is made up of carbohydrates, proteins and fats.
2. Define this scientific word and use it in context. 'digestion'
Digestion is the process of breaking down large food molecules into smaller molecules that can be absorbed into the blood. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Food is absorbed without being digested; or "goodness" from food is what is absorbed. Correction: The lesson explores the roles of mechanical and chemical digestion (by enzymes) of different food types into small molecules to be absorbed.
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