Which of the following is an example of a channel protein?

• A. ATP synthase
• B. Aquaporin
• C. Integrin
• D. G-protein coupled receptor

Answer: (B)

Verified step by step guidance

1. Understand the role of channel proteins: Channel proteins facilitate the transport of substances across a cell membrane by providing a passageway through which molecules can move.
2. Identify the function of aquaporins: Aquaporins are a type of channel protein specifically responsible for the transport of water molecules across cell membranes.
3. Differentiate between channel proteins and other types of proteins: Channel proteins, like aquaporins, form pores in the membrane, whereas other proteins like ATP synthase are involved in energy production, integrins are involved in cell adhesion, and G-protein coupled receptors are involved in signal transduction.
4. Recognize the structural characteristics of aquaporins: Aquaporins have a unique structure that allows them to selectively transport water molecules while preventing the passage of ions and other solutes.
5. Conclude that aquaporins are the correct example of channel proteins from the given options, as they directly facilitate the movement of water across cell membranes.