# Digestive system

The organs that break food into small molecules the blood can carry around the body.

Biology (school) · Part 03: The human body · Card 2 of 11 · Last updated 2026-10-19

## Analogy

A disassembly line that cuts big things into tiny pieces.

## In practice

Enzymes break starch into glucose, protein into amino acids and fat into fatty acids and glycerol.

## Practice

### Flashcards

- **What do enzymes break protein into?** Amino acids.

## Questions people ask

### What does bile do in digestion?

Bile is made in the liver and stored in the gall bladder. It is alkaline, which neutralises acid from the stomach so enzymes in the small intestine work well. It also breaks large fat drops into tiny droplets, giving lipase enzymes more surface area to work on.

### Which enzymes digest which food?

Carbohydrases such as amylase break starch into sugars. Proteases such as pepsin break proteins into amino acids. Lipases break fats into fatty acids and glycerol. Each enzyme matches one type of food molecule, and different parts of the gut make them, such as the mouth, stomach and pancreas.

## Related concepts

- [Villi](https://studyvisually.com/learn/science/biology-school/biology-school-part-3/biology-school-part-3-concept-3)

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