Movement and accumulation of ions across a membrane against their concentration gradient can be explained by
- Facilitated Diffusion
- Passive Transport
- Active Transport
- Osmosis
Answer
(3) Active Transport
Solution
Movement of ions against their concentration gradient (uphill) needs energy from ATP and is carried out by membrane pumps; this is active transport. Facilitated diffusion, passive transport and osmosis all occur only along the gradient, without energy.
Answer: (3)