🍫 Digestive System

Chapter: Human Body Systems · Level ★★☆ · Time: 20 min

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NameClassDate

After this worksheet you can

Order the digestive pathwayMatch enzyme to substrate/productExplain villi functionRecall gastric juice components

📚 Quick Recap

🎯 What you'll practice: The digestive pathway and the enzyme-substrate-product relationships that MDCAT tests.

🧮 Section B · Problem Solving ● INTERMEDIATE 2 + 3×3 = 11

5Gastric juice contains HCl and .

6The large intestine mainly reabsorbs .

7Name the enzyme that converts lactose into glucose and galactose.

8List the full digestive pathway from mouth to anus.

9Why do villi and microvilli increase absorption efficiency?

🚀 Section C · Challenge ● CHALLENGE 5

10Pepsin works at pH 2, but as food enters the small intestine it becomes neutral/alkaline. Explain why pepsin would not continue to function in the small intestine.

💭 Reflection — the most useful thing I learned:

A ___/4 B ___/11 C ___/5 Total ___/20 Teacher's Signature Parent's Signature

✂ answer key — fold or cut before handing out

1-B 2-A 3-B 4-B | 5 = pepsinogen 6 = water 7 = lactase 8 = mouth → oesophagus → stomach → small intestine → large intestine → rectum → anus 9 = they dramatically increase the surface area of the small intestine lining, allowing more nutrient molecules to be absorbed per unit time | 10 = Like all enzymes, pepsin has an optimum pH range (around pH 2) at which its active site retains the correct shape to bind its substrate; in the near-neutral/alkaline environment of the small intestine, pepsin's structure is no longer stable at that pH, denaturing or losing its functional shape, so it stops being an effective catalyst there — protein digestion instead continues via different enzymes suited to that pH.

📄 Need offline practice?Print this worksheet or open the one-page cheat sheet.

🗒 Cheat Sheet

🧠 Section A · Concept Check ● BEGINNER 4 × 1 = 4

🧮 Section B · Problem Solving ● INTERMEDIATE 2 + 3×3 = 11

🚀 Section C · Challenge ● CHALLENGE 5