Which of the following is considered a type of active process in the cell membrane?

Active processes in the cell membrane require energy, typically in the form of adenosine triphosphate (ATP), to move substances against their concentration gradient. Primary active transport specifically involves the use of ATP to transport ions or molecules from an area of lower concentration to an area of higher concentration.

In primary active transport, a protein in the cell membrane, often referred to as a pump (like the sodium-potassium pump), directly uses ATP to change its conformation and move substances across the membrane against their natural flow. This is crucial for maintaining concentration gradients that are essential for many cellular functions, including nerve impulse transmission and muscle contraction.

Other methods of movement across the cell membrane, such as facilitated diffusion, filtration, and osmosis, are considered passive processes. They do not require energy because they rely on the natural movement of substances along their concentration gradients. Thus, recognizing primary active transport as an active process highlights the unique role of energy in certain membrane transport mechanisms.