What can physicists do?
Physicists explain experimental observations (e.g. a particular property of a cellular membrane) mathematically, based on natural principles such as the conservation of energy. For example, if two particular cellular membranes are observed to fuse (blend together), a favorable circumstance of molecular interactions must have occurred. The physicists measure those forces, then calculate when and how the favorable scenario occurs, and then test the results against new experiments. Often, the whole process goes in reverse to end up with a quantitative determination of the previously unknown forces.
Compared to more applied disciplines, basic Physics research can at times be slow ("Really?" would say my collaborators.) But I can tell you why. First, the physicist, a little mathematician of the sort, will start by labeling everything with x, y, z, and many Greek letters. Then add plenty of exotic decorations, including arrows, hats, circles, and squiggles, causing the MS Word editor to turn automatically to Swedish. This theoretical step, never as easy as it sounds, provides a description of the system in terms of what we call "degrees of freedom". Whether they like it or not, this mathematical assignment applies to biological membranes too. Once this assignment is done, the physicists-proper is briefly activated, just enough to activate in turn the engineer, one other facet of the physicists (and the only practical one as you can recognize). The practical side of a physicists has to come up with the proper laboratory setup to measure all the many x's and y's, with and without the squiggles. The physicists' many faceted job then is to integrate measurement and theory in a meaningful way such that the cause and effects can be distinguished.
Suppose you go to school whenever the sun is up. What causes what is not always as clear as in this particular example!