Which term describes the difference in solute concentration across a distance?

Which term describes the difference in solute concentration across a distance?

• A. Concentration gradient
• B. Energy
• C. Isotonic
• D. Ion channel

Answer: (A)

The main idea here is concentration gradient—the difference in solute concentration from one location to another. This gradient is what drives diffusion, as particles tend to move from places with more solute to places with less, until the concentrations even out. The steeper the gradient, the faster diffusion occurs. The other terms don’t describe this difference: energy is a broad concept related to work and movement, isotonic describes equal solute concentrations between two compartments, and an ion channel is a membrane protein that lets ions pass, not the actual concentration difference.

The main idea here is concentration gradient—the difference in solute concentration from one location to another. This gradient is what drives diffusion, as particles tend to move from places with more solute to places with less, until the concentrations even out. The steeper the gradient, the faster diffusion occurs. The other terms don’t describe this difference: energy is a broad concept related to work and movement, isotonic describes equal solute concentrations between two compartments, and an ion channel is a membrane protein that lets ions pass, not the actual concentration difference.