← Biology XI
📖 Lecture 🎬 Walkthrough 🧪 Practical
Class XI · Chapter 13 · Walkthrough

Nutrition — from food to fuel

01 · The journey

Through the alimentary canal

Food is ingested, digested along the canal, absorbed into the blood, assimilated by cells, and the waste is egested. ▶ Play to follow a mouthful from mouth to large intestine.

02 · Digestion

Enzymes do the cutting

Amylase turns starch into maltose, protease/pepsin turns protein into amino acids, and lipase turns fats into fatty acids + glycerol. Bile first emulsifies fat into droplets so lipase works faster.

03 · Absorption

Villi soak it up

Small soluble products are absorbed through millions of villi: a large surface area, a one-cell-thick wall, a capillary network for sugars & amino acids and a lacteal for fats.

🔬 Digestion viewerthe journey
Watch food move and break down.