Question

15 Which of the following is the reason why an aquaporin does not pass ions (such as Na+) through? A. The Nations are too small to pass through the pore rapidly enough B. The Nations are too large to pass through the narrow pore C. The Nations do not favorably interact with the wall of the pore and therefore cannot be dehydrated D. Two Asn residues in the channel prevent the passage of Na+ ions. E. A Na+ ion must become fully hydrated to pass through

Answer 1

15. Aquaporin does not allow/pass the ions such as Na+ through them because of 2 Asn residues in the channels prevent the passage of Na+ ions.The pore structure of aquaporin is like 3D hour glass like structure which prevents the entry of ions.The structure contains Asn-Pro-Aln at the pore opening.It has also been said that there are conical entrances at the pore with suitable angle opening avoids the entry of ions.

20. EIEE