In passive transport, how does increasing temperature generally affect the rate of diffusion of small molecules across a membrane or through a fluid?

• A. It stops diffusion by eliminating the concentration gradient.
• B. It has no effect on the rate of diffusion because diffusion depends only on concentration gradient.
• C. It increases the rate of diffusion because molecules have greater kinetic energy and move faster.
• D. It decreases the rate of diffusion because higher temperature increases molecular mass.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the concept of passive transport and diffusion. Passive transport is the movement of molecules across a membrane without the input of energy, driven by the concentration gradient.
2. Step 2: Recall that diffusion rate depends on factors such as concentration gradient, temperature, and the kinetic energy of molecules.
3. Step 3: Recognize that increasing temperature increases the kinetic energy of molecules, causing them to move faster.
4. Step 4: Faster molecular movement leads to an increased rate of diffusion because molecules cross the membrane or move through the fluid more rapidly.
5. Step 5: Conclude that increasing temperature generally increases the rate of diffusion, not stops or decreases it, and it does not eliminate the concentration gradient or affect molecular mass.