@ket9 This card is found from the Milesdown PDF & it seems like the distinction between “maintaining” and “facilitating” bidirectional transport is why this was defined for flippases. Although, an argument could be made that this is a hazy distinction, not one that someone could pick up going through this note.
Taking another look at this suggestion, you are correct that this is a mischaracterization of what flippases do. From the source below: “Flippases” (red) catalyze the transport of lipids toward the cytoplasm and require ATP, “floppases” (blue) catalyze the ATP-dependent transport of lipids away from the cytoplasm, and “scramblases” (purple) catalyze the bi-directional, non-energy-dependent transport of lipids.
Scramblases or floppases might be referenced in passages but I haven’t seen them tested in an MCAT question. With that said, I’ve edited the card to reflect what a flippase does. I’ve kept the other definitions in Extra since they are concise & wouldn’t add that much review time if viewed; if you find that these definitions for scramblases and/or floppases are just as important, please submit new note suggestions & include a reference to where they’ve been tested.