Chemotaxis is the movement of an organism or cell in response to chemical stimuli in its environment. This process allows cells, such as bacteria or white blood cells, to navigate toward beneficial substances like nutrients or away from harmful ones, enhancing their survival and function. In chemotaxis, cells detect chemical gradients, meaning they sense differences in concentration of specific chemicals. They then move toward higher concentrations of attractants or lower concentrations of repellents. This behavior is crucial in various biological processes, including immune responses and developmental biology.