Which of the following is an example of facilitated diffusion?

• A. Water moving through aquaporins
• B. Carbon dioxide diffusing out of a cell
• C. Glucose transport into a cell via a carrier protein
• D. Oxygen moving across the cell membrane

Answer: (C)

Verified step by step guidance

1. Facilitated diffusion is a type of passive transport that requires the assistance of a protein to move molecules across the cell membrane.
2. Identify the molecules involved in each option: water, carbon dioxide, glucose, and oxygen.
3. Determine which molecules require a protein to assist in their transport across the cell membrane. Water uses aquaporins, glucose uses carrier proteins, while carbon dioxide and oxygen do not require proteins.
4. Understand that facilitated diffusion is necessary for molecules that cannot pass freely through the lipid bilayer due to size or polarity, such as glucose.
5. Conclude that glucose transport into a cell via a carrier protein is an example of facilitated diffusion, as it requires a specific protein to assist in its movement across the membrane.