Talk:Aquaporin

Lead section is unclear
Good, but "could do better"! … Two hydrophobic loops contain conserved asparagine-proline-alanine NPA motif. Because aquaporin is usually always open and is prevalent in just about every cell type, it causes water to almost always flow to down its concentration gradient. This leads to a misconception that water readily passes through the cell membrane down its concentration gradient. … The first of these two sentences contains three puzzles for the non-specialist: This fragment: "it causes water to almost always flow to down its concentration gradient" contains two grammatical infelicities (since it would be better as "it almost always causes water to flow down its concentration gradient") and two further puzzles: I propose to improve the grammar, but will leave the rest to somebody better informed than I, meanwhile marking it. yoyo (talk) 04:41, 5 November 2019 (UTC)
 * 1) What does "conserved" mean in this context? (I have no idea.)
 * 2) What is "NPA" and how does it relate to the preceding compound word "asparagine-proline-alanine"? (I think it's an acronym of sorts, thus: "asparagiNe-Proline-Alanine", but who knows?)
 * 3) What does "motif" mean in this context? (I have only a glimmer of an idea, and it's this:  in music and the plastic arts, a "motif" is a small assemblage that occurs repeatedly, sometimes with variations.  Is the usage in biochemistry similar?)
 * 1) what is this "concentration gradient"?
 * 2) which direction is "down" that gradient?