What is the difference between chem 2e03 and chem 2oa3? Are they both the same? If I plan on applying to professional schools is there a downside to taking chem 2e03?

I haven't really heard about chem2e03 before, but it would depend on which program you were in. For life science students, they usually take chem2OA3. They are anti-requisites, though. For professional schools, you'd have to check the requirements for each individual school to see if they require one particular course over the other. Which program are you in, by the way?

If the professional school requires a lab and/or requires 2OB3 as well, then you need to take 2OA3.

Chem 2E03 has just tutorials, instead of labs. So if you're considering professional schools, some don't require Orgo at all, others will require one of or both 2OA3 and 2OB3.

2e03 is to just get a pass in the orgo field. If you want med school or anything further that uses orgo chem you have to take 2oa3/2ob3