2006 nissan altima starting problems and lurching?

I recently bought my 2006 nissan altima with 56k miles. It sometimes takes a while to start (7 seconds holding the key in ignition) and sometimes it takes 2 tries to start. Also, when it switches from the 1st to 2nd gear, it lurches forward. It's usually a violent lurch but sometimes it doesn't even happen. Whats the problem?