First off - study hard! The bar exam is tough enough without financial pressures over your head.
Let me try and address your second question first - there are many things that the Character and Fitness Committee will look at when determining your fitness for admission. The best advice I can give ytou there is to ALWAYS be honest, complete in your answers, and willing to accept responsibility if you have made mistakes. Remember your ethics course (if you have taken it already that is)? Candor before the tribunal. Be honest, and be forthright.
Bankruptcy is not a bar to admission, I know practicing attorneys who filed prior to admission and lawyers who filed after being admitted to the bar. It is my belief that a question you may have to answer is how you got into a bad financial situation, and what actions you took prior to filing bankruptcy to try and fix the problem. Bankruptcy is a privledge and not a right, but it is also seen as a legitimate way of dealing with financial difficulties that have become overwhelming. Go take a quick look at Local Loan Co. v. Hunt: bankruptcy is designed to give the honest but unfortunate debtor a fresh start.
One quick thing to remember - bankruptcy will (generally, except in cases of undue hardship) not eliminate your student loans (See 11 U.S.C. 523(a)(8) )