Term
| What is ATP, how is it formed, and how does it provide energy during metabolism? |
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Definition
| ATP is the immediately available source of energy for almost all bodily functions, including muscle contraction. It is formed when a phosphate group is added to ADP during phosphorylation, a process that requires a considerable amount of energy. It can also be produced through other reactions both with and without oxygen, (the latter being known as oxidative phosphorylation.) During metabolism, energy is released when the last phosphate group splits away from adenosine by the action of adenosine triphosphatase, (ATPase). |
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Term
| At rest, carbohydrates and fats are almost equally used as the primary substrates for energy. During high intensity exercise, more carbohydrates are used than any other substrate. |
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Definition
| What is the primary substrate used to provide energy at rest? During high-intensity exercise? |
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Term
| What is the role of PCr in energy production, and what are its limitations? Describe the relationship between muscle ATP and PCr during sprint exercise. |
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Definition
| PCr, (phosphocreatine), donates a phosphate to ADP to create ATP. It's limited by the fact that it is not freely available and is not used towards cellular work, as well as only lasting for a few seconds. Instead, it regenerates ATP to maintain a constant supply of it while resting. During sprint exercise, the body is rapidly using large amounts of energy, depleting your ATP and reducing it to ADP and P. This would trigger creatine kinase to separate P from Cr and donate it to the leftover ADP, maintaining ATP for continuous exercise in the process. |
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Term
| Describe the essential characteristics of the three energy systems. |
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Definition
ATP-PCr and glycolysis can both act without oxygen and are known together as anaerobic metabolism, while oxydative phosphorylation requires oxygen, and is known as aerobic metabolism.
ATP-PCr acts by separating phospate from creatine and donating the phosphate to ADP to maintain ATP. It acts quickly, but isn't sustainable since its ability to create energy only lasts for a few seconds.
Glycolysis produces ATP by breaking down glucose by using a pathway involving glycolytic enzymes. It is a more complex process than ATP-PCr.
The oxydative system is the most complex system of the three and is the only one that requires oxygen to function. It is defined as the system where the body breaks down substrates using oxygen by using respiration to break down substrates for energy. This takes place in the mitochondria as opposed to the cytoplasm like the other systems and can come from either carbohydrates (starting with glycolysis), or fats. |
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Term
| Why are the ATP-PCr and glycolytic energy systems considered anaerobic? |
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Definition
| ATP-PCr and glycolytic energy systems are considered anaerobic because they can act in the absence of oxygen. The oxidative system on the other hand, needs oxygen, which makes it aerobic. |
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