What is active transport in cells?

Active transport in cells is the process where substances are moved against a concentration gradient, requiring energy.

Active transport is a vital cellular process that moves ions or molecules across a cell membrane from a region of lower concentration to a region of higher concentration. Unlike passive transport, which works with the concentration gradient, active transport works against it. This process is 'active' because it requires the cell to expend energy, usually in the form of adenosine triphosphate (ATP).

The process of active transport is carried out by specific proteins embedded in the cell membrane. These proteins, known as transport proteins or carrier proteins, bind to the molecule or ion to be transported. The energy provided by ATP changes the shape of the protein, allowing the molecule or ion to be moved across the membrane.

Active transport is essential for many cellular functions. For example, it helps cells to absorb nutrients from their environment, even when the concentration of nutrients outside the cell is lower than inside. It also enables cells to maintain a suitable pH and ionic concentration, and to expel waste products.

There are two types of active transport: primary and secondary. Primary active transport directly uses energy to transport molecules across a membrane, while secondary active transport uses an electrochemical gradient to drive the transport of molecules.

In summary, active transport is a crucial process that allows cells to move substances against a concentration gradient, enabling them to maintain homeostasis and perform essential functions. It requires energy and is facilitated by specific proteins in the cell membrane.