Final answer:
The function of adenosine triphosphate (ATP) in living things is to serve as the B. main source of energy for cellular processes. It provides the energy required for various cell functions, such as muscle contraction and active transport. The correct option is B. It is the main source of energy for cellular processes.
Step-by-step explanation:
Adenosine triphosphate (ATP) plays a critical role in the life of cells and is the principal molecule for storing and transferring energy in cells. During cell respiration, ATP is produced, which then serves as the main energy source for many cellular processes. The function of ATP is to transfer the energy necessary for all sorts of cellular activities, such as muscle contraction, active transport across cell membranes, and the synthesis of biomolecules.
The structure of ATP consists of an adenosine molecule bound to three phosphate groups, known as the alpha, beta, and gamma phosphates. When one of these phosphate groups is removed through hydrolysis (an exergonic reaction), energy is released, which can then fuel endergonic reactions within the cell.
This process turns ATP into adenosine diphosphate (ADP) or adenosine monophosphate (AMP), depending on how many phosphates are released, and this reaction can be reversed to regenerate ATP during cellular respiration, which includes processes such as glycolysis and oxidative phosphorylation.
In summary, ATP acts as the energy currency of the cell, capturing chemical energy obtained from the breakdown of food molecules and releasitng it to fuel other cellular processes. Therefore, the correct option in response to the question about the function of ATP is B. It is the main source of energy for cellular processes.