Diffusion

In diffusion, the net movement of a substance travels down its concentration gradient. Explain what this means.

When diffusion has reached equilibrium, we say that the net movement of the molecules is zero. Does this mean the molecules stop moving? Why?

Simple diffusion can occur through a cell membrane. According to the video, what are some cell membrane characteristics that can affect the diffusion rate?

Does simple diffusion require an input of energy?

• Yes
• No
• Maybe

Is simple diffusion passive or active transport?

• Passive
• Active

Sometimes, a substance can only travel across a cell membrane via facilitated diffusion. What is facilitated diffusion?

Does facilitated diffusion require an input of energy?

• Yes
• No
• Maybe

Is facilitated diffusion passive or active transport?

• Passive
• Active

Diffusion is a critical process required for oxygen to leave the lungs and to enter the blood and for carbon dioxide to leave the blood and enter the lungs to be exhaled. Knowing what you know about how a substance travels in diffusion, in order for oxygen to leave the lungs and enter the blood, there would be a (HIGHER or LOWER) concentration of OXYGEN in the lungs compared to the blood.

• Higher
• Lower

Diffusion is a critical process required for oxygen to leave the lungs and to enter the blood and for carbon dioxide to leave the blood and enter the lungs to be exhaled. Knowing what you know about how a substance travels in diffusion, in order for carbon dioxide to leave the blood and enter the lungs, there would be a (HIGHER or LOWER) concentration of CARBON DIOXIDE in the alveoli compared to the blood.

• Higher
• Lower