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Introduction: Aquaporins or water channels are the proteins that help in the movement of water across the membrane. They are integral membrane proteins that form pores in the membrane to allow the transfer of water and sometimes small solutes.
Answer to Problem 1TY
Correct answer: Aquaporins are the protein channels that allow the transfer of water across the plasma membrane. Hence, the correct answer is option c.
Explanation of Solution
Reason for correct answer:
Aquaporins are a part of major intrinsic proteins that result in the pore formation. This allow the exchange of water molecules, and in some cases, small solute particles across the plasma membrane.
Option c. is given as “a protein channel in plasma membranes that facilitates the diffusion of water”.
The intrinsic proteins that cause the exchange of water molecules across the membrane are called aquaporins. Hence, the correct answer is option c.
Reasons for the incorrect answer:
Option a. is given as, “a channel protein that allows the influx of K+ into cells, causing water to flow in between the phospholipids of the plasma membrane”.
The aquaporins only allow the transfer of water molecules from extracellular fluid to the cytoplasm and not ions. Hence, option a. is incorrect.
Option b. is given as, “a type of blue-colored pore in the epidermal surfaces of plants”.
The aquaporins are not blue colored and are present in the plasma membrane of the cells for the transport of water. Hence, option b. is incorrect.
Option d. is given as, “a transport protein, or transporter, in plasma membranes that use protons to co-transport water”.
Aquaporins are the primary channels for the transport of water, some small neutral solutes and carbon dioxide through the plant cell membrane. They transfer the water molecules based on the concentration gradient. Hence, option d. is incorrect.
Option e. is given as, “none of the above”.
The aquaporins serve as protein channels that are hydrophobic and allow the transfer of water molecules. Hence, option e. is incorrect.
Hence, the options a., b., d., and e. are incorrect.
Aquaporins are present on the plasma membrane of the plant, animal, and bacterial cells. These protein channels serve as the key transport route for the water molecules. They are hydrophobic and can also transfer some neutral solutes and carbon dioxide across the plasma membrane.
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Chapter 39 Solutions
Biology
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