Anatomy and Physiology II Practice Test

What term describes the process when food molecules enter the cells and undergo chemical changes?

1. Digestion

2. Assimilation

3. Absorption

4. Metabolism

The correct answer is: Assimilation

The process described in the question refers to how food molecules are not only taken up by the cells but also undergo transformation to be utilized by the body. Assimilation is the correct term for this process, as it encompasses both the uptake of nutrients and their conversion into cellular components or energy. When food is consumed, it is first digested, broken down into smaller molecules. During absorption, these molecules pass through the intestinal wall into the bloodstream. However, assimilation specifically highlights what happens after absorption, where these molecules enter cells and are transformed through metabolic processes. This transformation is crucial because it enables the body to utilize the nutrients for growth, energy, and repair. In contrast, digestion refers to the mechanical and chemical breakdown of food into smaller components, while absorption involves the transport of those smaller molecules into the bloodstream. Metabolism encompasses all chemical reactions occurring in the body, including both the breaking down of nutrients for energy and the building up of these nutrients for essential bodily functions, but it is broader than just the process of assimilation. Thus, assimilation is the most precise term for when food molecules enter cells and undergo chemical changes.