Question

multiple choice 1 point
which process moves materials against a concentration gradient?
active transport
osmosis
simple diffusion
dialysis
facilitated diffusion

Explanation:

• Active transport: Requires energy (ATP) to move substances from an area of low concentration to high concentration (against the concentration gradient).
• Osmosis: Movement of water down its concentration gradient (from high to low water concentration, or low to high solute concentration), passive.
• Simple diffusion: Passive movement of substances down their concentration gradient (high to low).
• Dialysis: Separation based on diffusion across a semipermeable membrane, passive, down concentration gradient.
• Facilitated diffusion: Passive movement (with help of proteins) down the concentration gradient.

Only active transport moves materials against the concentration gradient.

Answer:

A. active transport