What favors the active transport in a membrane?
I was reading about active transport in membranes where ATP is used. ATP "reacts" with the protein pump and converts into ADP and also make a conformational change to the pump. Now this conformational change can transport molecules from low concentrations to high concentrations areas i.e. opposite in their concentration gradient. My problem is that for this to happen we must couple the hydrolysis of ATP with the "reaction" of transport along the membrane.
But I can't find it in textbooks and also I can't imagine if such coupling makes sense. In many textbooks it is stated that the energy that released due to the hydrolysis fo ATP is used to drive the pumping. I don't know if it is possible to couple two reactions with no common intermediates. 793
Also in the pictures that show the active transport like the one in the left side the molecules can't go through the lipids.
So the molecules just move from low to high but the moving from high to low (diffusion) is blocked because the molecules can't move through the lipids. In other words it isn't like molecules make something that it would be otherwise violated because at first the motion from one side to the other is blocked. I mean even if we have no ATP the molecules won't flow from high to low concentration. Then what is the point of "active" transport? For a moment I thought to describe the above scheme for active transport as the following reaction: $$\ce{ATP + H2O + M_{in}} \rightleftharpoons \ce{ADP + P_i + M_{out}} $$
Which can be thought as the sum of:
$$\ce{ATP + H2O } \rightleftharpoons \ce{ADP + P_i}$$
and
$$\ce{M_{in}} \rightleftharpoons \ce{M_{out}}$$
But as I stated I haven't find a coupling reaction with no common intermediates and also it doesn't make sense to write the second equilibrium as the molecules can't go through the lipids. Also from the second reaction we should expect the concentrations on both sides to be equal (because the equilibrium constant must be equal to unity) no matter the concentration of ATP.
So can the first equilibrium alone describe the "active" transport? I mean if this reaction is exergonic then indeed by varying the amount of ATP we can alter the concentration of M outside of the membrane due to the Le Chatelier principle.
Edit ATP hydrolysis causes conformational changes to the protein channel which in turns "passes" molecules from one side to the other. Fine. But what if the lipids were permeable to the molecules? Then shouldn't the two concenctrations on the two sides (in and out) be equal or because the ATP hydrolysis is exergonic we will expect to have an imbalance in the concentrations? 453