Digestion and the gut
Digestion breaks huge food molecules into tiny ones your body can absorb — and it needs both chemical helpers and a whole community of bacteria.
Part of your national curriculum
- Biology: structure and function: Understand the tissues and organs of the human digestive system, including the role of enzymes and the importance of bacteria in the gut
Lesson overview
What you'll learn in this lesson
Understand the tissues and organs of the human digestive system, including the role of enzymes and the importance of bacteria in the gut
Key learning points
- • The journey of food
- • Enzymes speed up digestion
- • Gut bacteria
This lesson at a glance
- 28 minutes
- 17 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 17
Visual introductionPicture this
Digestion and the gut
Digestion breaks huge food molecules into tiny ones your body can absorb — and it needs both chemical helpers and a whole community of bacteria.
In a nutshell
Understand the tissues and organs of the human digestive system, including the role of enzymes and the importance of bacteria in the gut
Learning cycle
Part 2 of 17
Learning cycle 1 of 2
Part 1 · The journey of food
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 17
Learn
The journey of food
Food travels from the mouth through the oesophagus to the stomach, then the small intestine, where most digestion and absorption happens, and finally the large intestine, where water is absorbed before waste leaves as faeces.
Reset break
Part 4 of 17
Pause
That's sitting 1 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 17
Learn
Enzymes speed up digestion
Enzymes are biological catalysts. Amylase (in saliva and the small intestine) breaks starch into sugars; protease breaks proteins into amino acids; lipase breaks fats into fatty acids and glycerol. Each enzyme works best at a specific pH and temperature.
Quick check
Part 6 of 17
Quick check
Part 7 of 17
Reset break
Part 8 of 17
Pause
That's sitting 2 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 17
Learning cycle 2 of 2
Part 2 · Gut bacteria
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 17
Learn
Gut bacteria
Trillions of bacteria live in the large intestine. They help break down fibre that human enzymes cannot digest, produce some vitamins (such as vitamin K), and support the immune system by competing with harmful microbes for space and food.
Quick check
Part 11 of 17
Reset break
Part 12 of 17
Pause
That's sitting 3 of 4 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 13 of 17
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 14 of 17
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
____ are biological catalysts.
They help break down fibre that human enzymes cannot digest, produce some vitamins (such as vitamin K), and support the immune ____ by competing with harmful microbes for space and food.
Challenge round
Part 15 of 17
Game · Recall cards
What does amylase break down?
Card 1 of 4
Mastery quiz
Part 16 of 17
Marked quiz
End of lesson quiz: Digestion and the gut
4 questions, marked with the reasoning shown. No timer.
1. What does amylase break down?
2. Where does most digestion and absorption occur?
3. What is one benefit of gut bacteria?
4. Which enzyme breaks down protein?
Lesson round-up
Part 17 of 17
Lesson round-up
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Understand the tissues and organs of the human digestive system, including the role of enzymes and the importance of bacteria in the gut