Passive transport and active transport are two different processes involved in moving substances across cell membranes:
1. Passive transport:
Passive transport does not require energy input from the cell. It relies on the natural movement of molecules from an area of high concentration to an area of low concentration. This process is driven by the concentration gradient, meaning molecules move spontaneously to achieve equilibrium without the cell expending energy. An example of passive transport is simple diffusion, where small non-polar molecules like oxygen and carbon dioxide move freely across the cell membrane.
2. Active transport:
Active transport, on the other hand, requires energy in the form of adenosine triphosphate (ATP) to transport molecules against their concentration gradient, from an area of low concentration to an area of high concentration. This process allows the cell to accumulate substances that are needed in higher concentrations inside the cell compared to their surroundings. An example of active transport is the sodium-potassium pump, which maintains the concentration gradients of sodium and potassium ions across the cell membrane.
In summary, the main difference between passive transport and active transport is that passive transport does not require energy input from the cell and occurs along the concentration gradient, while active transport requires energy and moves substances against the concentration gradient.
