I think that's a bit harsh. I think everyone knows that classes differ at schools, with different topics being taught or emphasized.
For example, my intro bio class was for my molecular bio major, so we did nothing with plants. I know many intro bio classes cover topics like that, but we have three bio majors at my school, with three significantly different intro classes. Being lost in this certain intro class does not mean that the previous bio class was worthless.
Theoretically, if you take a "cellular and molecular biology" class, it should cover the same material at any school, from the beginning chem, to the organelles in plants and animals, to DNA and all of the associated processes. I'm a bit surprised that you didn't end up covering plant stuff, as there would be no reason for a "molecular biology" class to exclude them. Luckily, I haven't heard of any MCAT questions covering intense plant information.
I guess I could be wrong, but I would be pretty surprised if there is as big of a variance in the class material between schools as you think. Obviously, there will be a different emphasis (mine was genetics), but overall, the MCAT and adcoms expect all pre-meds to walk away from a molecular biology class with the same fundamental knowledge, regardless of what the teacher happened to be researching at the time. If your class is excluding any information, or at least not giving you enough of a focus on that information for you to have a reasonable expectation of retaining it as well as the average pre-med, then there might be an issue with the class.
I have no problem using myself as an example. For some reason, during my time at a local community college, I went through my molecular biology class and picked up very little about DNA replication, transcription, translation, and the overall differences between lipids, proteins, and amino acids. We spent a great deal of time on crosses and genetic research methods, but for some reason, I didn't get everything I was supposed to from the class, even though I did feel like I studied. I have no problem admitting that my teacher was probably not as interested in teaching those portions and rushed through them, since her research was focused at a higher level of genetics. I had to reteach myself that material in the summer I studied for the MCAT.
I still probably could have gotten by the average cell biology lab, though. They don't tend to be nearly as difficult as chem or ochem labs...