Aquaporins

For a long time scientists believed that water moved freely through a cell membrane even though the center of the cell membrane is hydrophobic. They thought that water "leaked" across the cell membrane, but we now know that this is not true.

In the early 1990s scientists measured the movement of water across a cell membrane and found that it was too rapid to be "leaked" across the bilayer membrane. They found that the cell membrane contained water-specific transport proteins, called aquaporins, that facilitated the movement of water. These proteins do not actively move water, rather they are believed to be simple gates that open and close in response to different conditions.

• Does the word aquaporin adequately describe the function of this protein?
• If you could come up with another word, what word would you propose to describe a water-specific protein?
• What is a transport protein?
• How would you incorporate aquaporins into the water potential discussion of plant cells?

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