Question

Which of the following energy substrates cannot be depleted during extreme exercise intensities or duration?

- creatine phosphate
- glycogen
- water
- ATP

Answer 1

During extreme exercise, creatine phosphate and glycogen provide energy for muscle contraction but can be depleted, unlike water which does not get depleted in the same manner.

Step-by-step explanation:

The energy substrates that can be depleted during extreme exercise are creatine phosphate, glycogen, and ATP. Creatine phosphate acts as a quick energy reserve for the first few seconds of muscle contraction, whereas glycogen is used for longer activities, eventually leading to ATP generation through the process of glycolysis.

Given that both creatine phosphate and glycogen can be depleted, and ATP levels are maintained only through substrate consumption and regeneration, water is the correct answer as it cannot be depleted in the same way during exercise.

Answer 2

Water is the correct option that cannot be depleted during extreme exercise as it is not directly used as an energy substrate like creatine phosphate, glycogen, or ATP, all of which can be depleted.

Step-by-step explanation:

During extreme exercise intensities or duration, various energy substrates are used by the body. These include creatine phosphate, glycogen, and ATP. Creatine phosphate serves as a rapid source of energy, providing ATP during the first few seconds of intense muscular activity. It is rapidly depleted after about 8-10 seconds. Glycogen, stored in muscles, can also be broken down through glycolysis to generate ATP, lasting around 90 seconds of high-intensity activity. ATP, already present in the muscle cells, is quickly utilized during muscular contraction but is continuously synthesized from other substrates like creatine phosphate and glycogen. Water, on the other hand, does not serve as an energy substrate but is vital for maintaining overall cellular function and is not depleted in the same way as the other molecules during exercise.

Therefore, when given the options of creatine phosphate, glycogen, ATP, and water, the correct option that cannot be depleted during extreme exercise intensities or duration is water. While the other substrates can be exhausted, water is crucial for hydration and many other cellular processes and is not directly used as a source of energy during muscular contraction.