Comparison of Active and Passive Transport
Cells require a constant supply of nutrients and elimination of waste to maintain their functions. To accomplish this, they employ two different methods of transportation: active and passive transport. Both have their unique characteristics and functions.
- Passive transport is the movement of molecules or ions across the cell membrane without any energy input from the cell. This process depends solely on the concentration gradient, which is the difference in the concentration of the solute between two regions, to drive the movement of molecules from higher to lower concentrations. Passive transport can be further divided into three types: diffusion, osmosis, and facilitated diffusion.
- Active transport, on the other hand, is the movement of molecules or ions across the cell membrane against the concentration gradient, from lower to higher concentrations. This process requires the input of energy from the cell to act as a driving force for the movement of molecules. Active transport can be further divided into primary and secondary active transport.
Differences between the two types of transport are summarized in the table below:
| Active Transport | Passive Transport |
|---|---|
| Requires energy input from cell | No energy input required |
| Moves molecules against the concentration gradient | Moves molecules along the concentration gradient |
| Can move molecules from low to high concentration | Can only move molecules from high to low concentration |
| Examples include primary and secondary active transport | Examples include diffusion, osmosis, and facilitated diffusion |
In summary, both active and passive transport are essential processes for maintaining the proper functioning of cells. The difference lies in their mechanisms and the requirements for energy input. Passive transport relies on the concentration gradient, while active transport requires the input of energy from the cell to move molecules against the gradient.