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What is bioenergetics?
- (ACSU)
- The body's ability to acquire, convert, store, and utilize energy
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What is adenosine triphosphate (ATP)?
Immediate source of energy for all cellular activities, including muscle contraction
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What is ATP broken down to?
Adenosine diphosphate (ADP)
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How is ATP replenished and why does it need to be replenished?
- Replenished via other energy pathways that replace ATP as it's used;
- Needs to be replenished because only a limited amount is stored in the cell
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What is the phosphagen system?
Energy pathway composed of ATP and phosphocreative (pCr) stored in muscle fibers
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What does the enzyme creatine kinase do?
Through activity it helps PCr yeild its phosphate group so that it can be added to ADP to synthesize ATP
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How is the phosphagen system used for exercise? What are its limitation?
- Immediately available for use by the working muscles, but is limited in its capacity to supply energy;
- During all-out-effort exercise, stored ATP and PCr in phosphagen system can only sustain activity for 30 seconds
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What is the nonoxidative system referred to and why?
Referred to as anaerobic pathway because oxygen is not required for it to produce ATP
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What produces ATP in the nonoxidative system?
Only carbohydrates (glucose)
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What happens in the nonoxidative system as the absence of oxygen occurs?
Breakdown of carbs yeilds lactic acid (lactate), which can contribute to muscle fatigue as it accumulates.
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When is the nonoxidative system the main provider of energy to the body?
Working muscles in athletic events lasting 30 seconds to 3 minutes
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What is the oxidative system referred to and why?
aerobic system because the APT-producting pathway requires oxygen it to proceed
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What synthesizes ATP in the oxidative system?
- Carbohydrates
- Fats (lipids)
- Sometimes protein
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What are the metabolic by-products of oxidative phosphorylation and what effect do they have on the muscle?
- By-products are water and carbon dioxide;
- Have no fatiguing effect on the working muscles
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When is the oxidative system the main provider of energy to the body?
Activities lasting more than 3 minutes
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What are the disadvantages of the oxidative system?
- Relatively slow in synthesizing ATP demaneded by exercising muscles;
- If inadequate oxygen is delivered, it depends on the nonoxidative system to produce energy resulting in lactate accumulation
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What is the anaerobic threshold/lactate threshold?
The point at which energy production results in lactate accumulation due to inadequate oxygen to the muscles
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What does endurance training do for ATP production and why?
- Increase the capacity of the oxidative system to produce ATP;
- Increases the storage of energy substrates (carbs/fats) used in the oxidative pathway
- Because of increased mitochondrial density, leading in increase in enzymes and other proteins involved in oxidative synthesis of ATP
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What does resistance training do for ATP production and how?
- Improves that capacity of the muscle to produce ATP anaerobically;
- Increases the glycolytic enzymes used in the anaerobic pathway along with the amount of glycogen stored in the muscle
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