Question: 106 Movement and accumulation of ions across a membrane against their concentration gradient can be explained by
(1) Passive Transport
(2) Active Transport
(3) Osmosis
(4) Facilitated Diffusion
Answer: Option (2)
Explanation:
Movement of ions against their concentration gradient requires energy.
In active transport, ions are moved from a region of lower concentration to a region of higher concentration.
This process is carried out by specific membrane proteins and requires energy in the form of ATP.
Passive transport, facilitated diffusion, and osmosis occur along the concentration gradient and do not require energy.
Therefore, movement and accumulation of ions against their concentration gradient is explained by active transport.