Wiley Open Access is a decent place to start. This link should help:
http://www.wileyopenaccess.com/view/searchResults.html?o=score&q=molecular+biology&jsearchType=AR%2CLI%2CJA
However, you should have free access to all kinds of online articles through your university. Do a little digging and you can probably get in to several journals Wiley won't allow (at least not for free).
As for confidence, well, it's tough to say. I outright guessed on one question, and there were a few others where I
think my answer was right, but I wouldn't swear to it. And that's kinda how the MCAT rolls. I spent several hundred hours preparing for this exam and had virtually all the content down. But the MCAT isn't an exercise in regurgitation of trivia. How you assimilate new information and are able to logically reason through unfamiliar situations is just as important as your knowledge base. And, just like all other skills, your critical reasoning needs to be developed through hard work and practice.
In short, I certainly didn't get everything right and I'm not even particularly confident I got a high score. But I know I did what I could to give myself a shot at my target score. And, in the end, that's about all you can really do.