Digestion-and-Enzymes-Worksheet - Free Printable

Let's solve the Digestion and Enzymes Worksheet step by step, based on the diagram of the human digestive system.

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1. a. Label the diagram

We need to identify and label the six parts indicated by lines in the diagram. Based on standard human anatomy:

- Top left (mouth): Mouth
- Top right (throat/neck area): Oesophagus (Esophagus)
- Middle left (large organ above stomach): Liver
- Middle right (J-shaped organ): Stomach
- Bottom left (coiled tubes): Small intestine
- Bottom right (larger looped tube): Large intestine (Colon)

> ✔ So, the correct labels are:
> - Mouth
> - Oesophagus
> - Liver
> - Stomach
> - Small intestine
> - Large intestine

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1. b. Physical digestion takes place at two places in the system. Circle two labels to show the places where this occurs.

Physical digestion refers to the mechanical breakdown of food into smaller pieces without changing its chemical structure.

Two main sites of physical digestion:
1. Mouth – Chewing (mastication) breaks food into smaller pieces.
2. Stomach – Muscular contractions churn food into a semi-liquid mixture called chyme.

> ✔ So, you should circle:
> - Mouth
> - Stomach

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1. c. Explain why physical digestion is important.

Answer:

Physical digestion is important because it increases the surface area of food particles. This allows digestive enzymes to act more efficiently during chemical digestion. Smaller food pieces also move more easily through the digestive tract and are better prepared for nutrient absorption in the small intestine.

> ✔ Example answer:
> *Physical digestion breaks down large food particles into smaller ones, increasing the surface area for enzymes to work on. This makes chemical digestion more efficient and helps nutrients to be absorbed more easily in the small intestine.*

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✔ Final Answers Summary:

#### a. Labels:
- Top left → Mouth
- Top right → Oesophagus
- Middle left → Liver
- Middle right → Stomach
- Bottom left → Small intestine
- Bottom right → Large intestine

#### b. Circle:
- Mouth
- Stomach

#### c. Explanation:
Physical digestion is important because it breaks food into smaller pieces, increasing surface area for enzymes to act on, which speeds up chemical digestion and improves nutrient absorption.

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