F4 biology(osmosis)問題~~~~~

You need to understand the word "osmosis". This word is specific to water, like the above definition says.

But you should also know, diffusion is a broader term to describe the movement of molecules. (no matter to the present of a selectively permeable membrane.)

You can use diffusion to describe water movement when you focus at the part that the membrane is not present.

Anyway, we usually use diffusion to describe movement of molecules rather than water in a medium that a mixture of water and other molecules.

osmosis同diffusion 係有可能同時發生...

首先你要知道osmosis同diffusion ge 定義...osmosis 係水分子透過selectively permeable membrane從high water potential to low water potential ge 移動, diffusion 就係任何分子由高濃度至低濃度的移動...

我假設依家細胞外的水勢比細胞內低...咁水分子就會由細胞內透過osmosis 去到細胞外...同時, 細胞外某些分子的濃度比細胞內低(因為細胞外的水勢比細胞內低), 只要分子的size 細 (例如glucose), 就能用diffusion 透過cell membrane 進入細胞...這就是diffusion 同osmosis 同時進行的例子...

Osmosis is diffusion of water throught selectively permanable membrance.