Biology · AQA Paper 1
Respiration and Metabolism
How cells release energy by aerobic and anaerobic respiration, how the body responds to exercise, and how the reactions of metabolism build and break down carbohydrates, proteins and lipids. Matches AQA GCSE Biology 4.4.2 (respiration). Every lesson is for both Combined Science and separate Biology; the Higher tier extras are marked.
Lessons
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1
Aerobic and Anaerobic Respiration
Every living cell is transferring energy from glucose all the time. This lesson covers respiration as an exothermic reaction, the equations for aerobic and…
8 terms -
2
Response to Exercise
During exercise the muscles need far more energy than at rest. This lesson explains how the heart rate, breathing rate and breath volume change, what happens…
8 terms -
3
Metabolism
A cell carries out thousands of chemical reactions at once. This lesson names them collectively as metabolism, and links together how sugars, amino acids…
8 terms
Key terms in this chapter
All 24, gathered from every lesson.
- Respiration
- The exothermic reaction in living cells that transfers energy from glucose.
- Exothermic reaction
- A reaction that transfers energy to the surroundings.
- Aerobic respiration
- Respiration that uses oxygen, and transfers a large amount of energy.
- Anaerobic respiration
- Respiration without oxygen, which transfers much less energy.
- Lactic acid
- The product of anaerobic respiration in muscles.
- Ethanol
- The alcohol made when yeast and plant cells respire anaerobically.
- Fermentation
- Anaerobic respiration in yeast cells.
- Mitochondria
- The parts of a cell where most of the reactions of aerobic respiration take place.
- Heart rate
- The number of times the heart beats each minute.
- Breathing rate
- The number of breaths taken each minute.
- Breath volume
- The volume of air taken in with each breath.
- Lactic acid
- A product of anaerobic respiration in muscles.
- Muscle fatigue
- When muscles stop contracting efficiently after long periods of vigorous activity.
- Oxygen debt
- The extra oxygen the body needs after exercise to remove the lactic acid that has built up (Higher tier).
- Recovery time
- The time taken for the heart rate to return to its resting rate after exercise.
- Oxygenated blood
- Blood carrying a lot of oxygen, which is supplied to the muscles.
- Metabolism
- The sum of all the reactions in a cell or the body.
- Synthesis
- Building a larger molecule from smaller ones.
- Glycogen
- A carbohydrate in which animals store glucose, in the liver and muscles.
- Cellulose
- A carbohydrate made from glucose that strengthens plant cell walls.
- Amino acid
- A small molecule that is joined with others to make proteins.
- Fatty acid
- A small molecule that joins with glycerol to make a lipid.
- Glycerol
- A small molecule that joins with three fatty acids to make a lipid.
- Urea
- A waste substance made from the breakdown of excess protein, which is excreted.