36. In a hypertonic solution, water flows through aquaporins embedded in the plasma membrane of the cell. This type of transport is best known as which of the following?
Answer: C
Osmosis is the correct process occurring in a hypertonic solution.
In a hypertonic solution, water moves across the plasma membrane through aquaporins, which are specialized channels that facilitate the flow of water. This movement of water toward a higher concentration of solutes is known as osmosis.
A) active transport
Active transport involves the movement of substances against their concentration gradient, requiring energy input, typically in the form of ATP. Since the flow of water through aquaporins in a hypertonic solution occurs passively and does not require energy, this option is incorrect.
B) diffusion
Diffusion refers to the movement of molecules from an area of higher concentration to an area of lower concentration, but it is a broader term that does not specifically address the movement of water. While osmosis is a specific type of diffusion, diffusion alone does not capture the specific mechanism for water transport in this context, making this option incorrect.
C) osmosis
Osmosis specifically describes the movement of water across a selectively permeable membrane in response to solute concentration differences. In the context of a hypertonic solution, water flows out of the cell through aquaporins toward the area of higher solute concentration, making this option the correct answer.
D) facilitated diffusion
Facilitated diffusion refers to the process by which substances move across a membrane with the help of transport proteins, but it does not specifically denote the movement of water. While aquaporins facilitate the diffusion of water, the more precise term for this process when specifically discussing water movement is osmosis, thus rendering this option incorrect.
Conclusion
Osmosis is the most accurate term to describe the movement of water through aquaporins in a hypertonic solution, as it specifically addresses the behavior of water in response to solute concentration. Other options fail to encapsulate this distinct process, either by mischaracterizing the energy requirements or failing to specify the substance being transported. Therefore, osmosis is definitively the correct answer.