Final answer:
Passive transport is the movement of substances across the cell membrane without the use of energy, whereas active transport requires energy to move substances against their concentration gradient. Both are crucial for cellular homeostasis.
Step-by-step explanation:
The main difference between passive and active transport is the need for energy. Passive transport does not require cellular energy and moves substances down their concentration gradient, from a higher to a lower concentration. In contrast, active transport requires energy, often in the form of adenosine triphosphate (ATP), to move substances against their concentration gradient, from a lower to a higher concentration. Examples of Passive Transport
- Simple diffusion (e.g., oxygen and carbon dioxide)
- Facilitated diffusion with carrier proteins (e.g., glucose)
- Osmosis (e.g., water)
Examples of Active Transport include the sodium-potassium pump, which uses ATP to move sodium out of a cell and potassium into it, and vesicle transport, such as endocytosis, where substances are engulfed by the cell membrane to enter the cell and exocytosis, where substances are expelled. Both transport mechanisms are essential for maintaining cellular homeostasis, as they regulate the internal environment of the cell by controlling the movement of molecules across the cell membrane.