AQA · A-Level · Physical Education
Course version: 7582 · Version from Sept 2016
Energy systems: Energy transfer in the body.
Energy transfer means converting the chemical energy in food into usable cellular energy.
Checked against the AQA 7582 specification (opens in a new tab) on .
- Point 2 of 26
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Energy transfer means converting the chemical energy in food into usable cellular energy. ATP is the universal energy currency: breaking its terminal phosphate bond releases energy for muscle contraction. ATP is resynthesised from ADP and inorganic phosphate using energy from three systems. The ATP-PC system transfers phosphate from phosphocreatine to ADP very quickly but briefly. Anaerobic glycolysis breaks glucose or glycogen into pyruvate, yielding ATP without oxygen and forming lactate. The aerobic system uses oxygen in the mitochondria to oxidise glucose, glycogen or fat, producing carbon dioxide, water and large amounts of ATP. Learn the site, fuel, duration and by-products of each transfer route.
What earns the marks
- States that ATP is the universal energy currency and that its breakdown to ADP and inorganic phosphate releases energy for muscle contraction.
- States that ATP must be resynthesised from ADP and inorganic phosphate, and that this requires energy from food fuels.
- Describes the ATP-PC system as a fast, anaerobic transfer using phosphocreatine to rebuild ATP for short maximal bursts.
- Describes anaerobic glycolysis as the breakdown of glucose or glycogen to pyruvate, producing ATP without oxygen and forming lactate.
- Describes the aerobic system as oxygen-dependent oxidation of glucose, glycogen or fat in the mitochondria, producing carbon dioxide, water and large amounts of ATP.
- Identifies the by-products and limitations of each system, such as fatigue from lactate accumulation and the slow start of aerobic transfer.
- Applies the correct transfer route to a named activity or intensity.
Common mistakes and how to put them right
Thinking ATP is stored in large amounts.
Put it right: ATP stores are very limited and must be continuously resynthesised.
Believing energy transfer only happens in the muscles.
Put it right: It occurs in cells throughout the body, with muscle cells having high demand.
Confusing the fuel for anaerobic glycolysis with fat.
Put it right: Glycolysis uses glucose or glycogen, while fat is used aerobically.
Assuming the aerobic system produces lactate.
Put it right: Lactate forms when oxygen supply cannot meet demand, so it is associated with anaerobic glycolysis.
Exam tips
- Use the correct equation direction: ATP breaks down to ADP and inorganic phosphate, releasing energy, and is rebuilt from ADP and inorganic phosphate.
- Name the site of each process, such as the sarcoplasm for glycolysis and the mitochondria for aerobic oxidation.
- Link each energy transfer route to a sporting example so the answer shows application as well as knowledge.
Try the lesson
The start of the Energy systems: Energy transfer in the body. lesson, made from checked teaching notes for this specification point.
Have a go first
Which molecule is the immediate energy currency used by muscles to power contraction?
Listen
Energy transfer means converting the chemical energy in food into usable cellular energy. ATP is the universal energy currency: breaking its terminal phosphate bond releases energy for muscle contraction. ATP is resynthesised from ADP and inorganic phosphate using energy from three systems. The ATP-PC system transfers phosphate from phosphocreatine to ADP very quickly but briefly. Anaerobic glycolysis breaks glucose or glycogen into pyruvate, yielding ATP without oxygen and forming lactate. The aerobic system uses oxygen in the mitochondria to oxidise glucose, glycogen or fat, producing carbon dioxide, water and large amounts of ATP. Learn the site, fuel, duration and by-products of each transfer route. A strong answer earns marks for these points. States that ATP is the universal energy currency and that its breakdown to ADP and inorganic phosphate releases energy for muscle contraction. States that ATP must be resynthesised from ADP and inorganic phosphate, and that this requires energy from food fuels. Describes the ATP-PC system as a fast, anaerobic transfer using phosphocreatine to rebuild ATP for short maximal bursts. Describes anaerobic glycolysis as the breakdown of glucose or glycogen to pyruvate, producing ATP without oxygen and forming lactate. A common slip: Thinking ATP is stored in large amounts. Instead, ATP stores are very limited and must be continuously resynthesised. Exam tip: Use the correct equation direction: ATP breaks down to ADP and inorganic phosphate, releasing energy, and is rebuilt from ADP and inorganic phosphate.
Watch it explained
What is the one idea the video explains? Say it in a sentence.
Read the described scene instead
Energy transfer means converting the chemical energy in food into usable cellular energy. ATP is the universal energy currency. Breaking its terminal phosphate bond releases energy for muscle contraction, leaving ADP and inorganic phosphate. ATP stores are very limited, so ATP must be continuously resynthesised. ATP is rebuilt from ADP and inorganic phosphate. This resynthesis needs energy from food fuels, and three transfer systems can supply it. The ATP-PC system is fast but brief. Anaerobic glycolysis produces ATP without oxygen and forms lactate. The aerobic system uses oxygen in the mitochondria and produces large amounts of ATP. The ATP-PC system transfers phosphate from phosphocreatine to ADP very quickly. This rebuilds ATP without oxygen, but only briefly. It suits short maximal bursts, and its limitation is that it cannot sustain longer efforts. Anaerobic glycolysis breaks down glucose or glycogen to pyruvate. It yields ATP without oxygen and forms lactate. Glycolysis occurs in the sarcoplasm. When oxygen supply cannot meet demand, lactate accumulates and can contribute to fatigue. The aerobic system uses oxygen in the mitochondria. It oxidises glucose, glycogen or fat, producing carbon dioxide, water and large amounts of ATP. Fat is used aerobically. This route has a slow start because oxygen delivery and aerobic reactions take time. A common error is thinking ATP is stored in large amounts. In fact, ATP stores are very limited and must be continuously resynthesised. Energy transfer occurs in cells throughout the body, not only in muscles. Anaerobic glycolysis uses glucose or glycogen, not fat. The aerobic system does not produce lactate; lactate is linked to anaerobic glycolysis. To compare the systems, learn the site, fuel, duration and by-products of each. ATP-PC is fast and brief. Anaerobic glycolysis uses glucose or glycogen in the sarcoplasm and forms lactate. Aerobic transfer uses oxygen in the mitochondria to oxidise glucose, glycogen or fat, producing carbon dioxide, water and large amounts of ATP. Link each route to an intensity to show application.
Key words
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ATP as energy currency
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ATP resynthesis
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Anaerobic and aerobic transfer
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Fuels and by-products
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See every definition
- ATP as energy currency
- ATP is the universal energy currency, and breaking its terminal phosphate bond releases energy for muscle contraction.
- ATP resynthesis
- ATP is resynthesised from ADP and inorganic phosphate using energy from food fuels.
- Anaerobic and aerobic transfer
- Anaerobic glycolysis breaks glucose or glycogen into pyruvate without oxygen, while the aerobic system uses oxygen in the mitochondria to oxidise fuels.
- Fuels and by-products
- Glucose, glycogen or fat are used as fuels, and by-products include lactate, carbon dioxide and water.
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