This topic summary covers Knowledge Organiser: Respiration within Respiration for GCSE Biology. Topic 2: Respiration It is section 17 of 17 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Knowledge Organiser: Respiration
Key Terms
- Aerobic respiration — uses oxygen, high ATP yield
- Anaerobic respiration — no oxygen, low ATP yield
- Mitochondria — site of aerobic respiration
- Lactic acid — product of animal anaerobic respiration
- Fermentation — yeast/plant anaerobic respiration
- Ethanol — alcohol product of fermentation
- Oxygen debt — extra O2 needed post-exercise
- Exothermic — releases energy as heat
Must-Know Facts
- Aerobic: glucose + O2 → CO2 + H2O (+ energy)
- Anaerobic (animals): glucose → lactic acid
- Anaerobic (yeast): glucose → ethanol + CO2
- Aerobic yields ~36-38 ATP; anaerobic yields only 2 ATP
- Respiration is exothermic (releases heat)
- All living organisms respire continuously
- Lactic acid is cleared in the liver using extra oxygen
- Mitochondria are most numerous in high-energy cells
Common Marks Lost
- Confusing respiration with breathing
- Saying anaerobic respiration in muscles produces CO2 (it produces lactic acid)
- Not mentioning the liver in oxygen debt answers
- Confusing exothermic (respiration) with endothermic (photosynthesis)
- Not comparing ATP yields when asked to compare aerobic and anaerobic
- Saying only animals respire (all living things do)
Practice questions for Respiration
Where in the cell does aerobic respiration take place?
Give three uses of energy released from respiration.
Quick recall flashcards
Word equation for aerobic respiration?
glucose + oxygen → carbon dioxide + water
(+ energy released)
Is respiration endothermic or exothermic?
Exothermic — it releases energy from glucose.
This energy is used for movement, growth, and keeping warm.