welcome but again, you keep coming back to your original idea. Taking a course...or now 2 as you proposed, will have marginal impact on the wholesome of your app. Goro, one of sdn's trusted advisors, and an adcom at a DO school, has stated in various threads that retakes are ok so long as they prove competency. they value the whole "this is you of now and not of the past". If you do search these threads, you'll see folks who have completely retaken every single course on their transcript after some event of importance led them to the path of medicine.
If you haven't taken the MCAT then you should take biochem for that reason only...that and because of the fact that biochem is becoming a requirement throughout many schools.