Which substances are absorbed through co-transport in the body?

Co-transport, also known as secondary active transport, is a mechanism by which certain substances are absorbed into the body by utilizing the concentration gradient established by primary active transport. In this process, a molecule such as sodium moves down its concentration gradient, which simultaneously allows other substances to be transported against their concentration gradients.

Glucose and amino acids are absorbed primarily through co-transport with sodium ions in the intestines. When sodium is absorbed into epithelial cells lining the gut, it creates a potential difference that drives the uptake of glucose and amino acids into these cells. This mechanism is efficient and essential for providing the body with the necessary energy and building blocks, as glucose serves as a primary energy source, and amino acids are vital for protein synthesis and various metabolic processes.

Other options do not fit this mechanism. For instance, while sodium and potassium are critical electrolytes involved in various functions in the body, their absorption is not facilitated through the same co-transport system utilized by glucose and amino acids. Fructose is absorbed by facilitated diffusion, and vitamins and minerals each have distinct absorption mechanisms that do not involve co-transport in the same way as glucose and amino acids do. Thus, glucose and amino acids represent the classic examples of substances that are absorbed through co