Respiration: the reaction happening in you right now
Respiration is not breathing. Breathing moves air; respiration is a chemical reaction inside every living cell that releases the energy those cells run on.
Part of your national curriculum
- Biology: material cycles and energy: Understand aerobic and anaerobic respiration in living organisms, including the breakdown of organic molecules to enable all the other chemical processes necessary for life
Lesson overview
What you'll learn in this lesson
Understand aerobic and anaerobic respiration in living organisms, including the breakdown of organic molecules to enable all the other chemical processes necessary for life
Key learning points
- • Aerobic respiration
- • Anaerobic respiration
- • Why it is not optional
This lesson at a glance
- 25 minutes
- 20 parts to scroll through
- 4 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 20
Visual introductionPicture this
Respiration: the reaction happening in you right now
Respiration is not breathing. Breathing moves air; respiration is a chemical reaction inside every living cell that releases the energy those cells run on.
In a nutshell
Understand aerobic and anaerobic respiration in living organisms, including the breakdown of organic molecules to enable all the other chemical processes necessary for life
Learning cycle
Part 2 of 20
Learning cycle 1 of 2
Part 1 · Aerobic respiration
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 20
Learn
Aerobic respiration
glucose + oxygen → carbon dioxide + water. This happens continuously in cells, releasing energy for movement, growth, warmth and every other chemical process life needs. Cells that work hard, such as muscle and liver cells, contain many mitochondria.
Reset break
Part 4 of 20
Pause
That's sitting 1 of 5 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 20
Learn
Anaerobic respiration
When oxygen cannot arrive fast enough, human muscle cells switch to glucose → lactic acid. Far less energy is released per glucose molecule, and lactic acid builds up. Yeast follows a different anaerobic route: glucose → ethanol + carbon dioxide, which is why bread rises.
Quick check
Part 6 of 20
Quick check
Part 7 of 20
Reset break
Part 8 of 20
Pause
That's sitting 2 of 5 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 20
Learning cycle 2 of 2
Part 2 · Why it is not optional
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 20
Learn
Why it is not optional
Without respiration a cell cannot build proteins, pump substances across membranes or repair itself. Every other life process is paid for by the energy respiration releases.
Quick check
Part 11 of 20
Reset break
Part 12 of 20
Pause
That's sitting 3 of 5 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.
Quick check
Part 13 of 20
Explore the idea
Part 14 of 20
Worked example
Worked example: the end of a sprint
A sprinter's legs ache and their breathing stays fast after finishing. Explanation: during the sprint, oxygen delivery lagged behind demand, so muscles respired anaerobically and lactic acid built up. Continued deep breathing supplies the oxygen needed to break that lactic acid down, which is why recovery breathing outlasts the race.
Challenge round
Part 15 of 20
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
Reset break
Part 16 of 20
Pause
That's sitting 4 of 5 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 17 of 20
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Yeast follows a different ____ route: glucose → ethanol + carbon dioxide, which is why bread rises.
Without ____ a cell cannot build proteins, pump substances across membranes or repair itself.
Challenge round
Part 18 of 20
Game · Recall cards
What are the products of aerobic respiration?
Card 1 of 4
Mastery quiz
Part 19 of 20
Marked quiz
End of lesson quiz: Respiration: the reaction happening in you right now
4 questions, marked with the reasoning shown. No timer.
1. What are the products of aerobic respiration?
2. Why does anaerobic respiration release less energy than aerobic?
3. What causes muscle fatigue during intense exercise?
4. Aerobic respiration produces
Lesson round-up
Part 20 of 20
Lesson round-up
Ready when you are
Quiz score
Not sat
Games
Not played
Points this lesson
0
Best run
0 in a row
Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 20 · Watch & discover
How this is going
- Not looked at yet
Understand aerobic and anaerobic respiration in living organisms, including the breakdown of organic molecules to enable all the other chemical processes necessary for life