International Sports Sciences Association (ISSA) Trainer Practice Exam

What molecule is primarily used for storing and transferring energy in the body?

1. Glucose

2. Creatine

3. Adenosine triphosphate (ATP)

4. Lactate

The correct answer is: Adenosine triphosphate (ATP)

Adenosine triphosphate (ATP) is the primary molecule used for storing and transferring energy in the body due to its unique structure and function. ATP consists of three phosphate groups, and the energy stored within the high-energy bonds between these phosphate groups can be released when the bonds are broken, allowing the energy to be utilized for various cellular processes. This capability makes ATP essential for powering muscle contractions, nerve impulses, and biochemical reactions. Unlike glucose, which primarily serves as a source of energy through metabolic pathways, ATP is directly used by cells to perform work, making it the immediate energy currency of the cell. Although glucose, creatine, and lactate play roles in energy metabolism, they do not function in the same direct manner as ATP. Glucose is a carbohydrate that gets converted into ATP through glycolysis and cellular respiration, while creatine serves primarily as a reservoir for quick energy release in muscle cells but requires ATP to perform its function. Lactate is a byproduct of anaerobic metabolism and does not directly store or transfer energy in the same way ATP does. Thus, ATP stands out as the key molecule for energy transfer and utilization in the body.