someone just asked a similar question, so I'm just going to copy and paste what I wrote. I know your from UCLA because of the class title and so am I.
the answer to your question is that it depends on what schools you are applying to and also what major you are. If you are one of those traditional premedical majors like MCDB, pyschbio, biochem, my guess is that you don't need to take it. I'm an electrical engineering major and I don't have upper division bio lab courses, so I had to take LS1 to fulfill that requirement. The key here is the lab. LS2-4 are sufficient to fulfill most school's one year requirement of biology but you are missing one quarter of lab because LS4 does not have a lab component. You need one year of bio classes with lab. So what you can do is take LS2-4 and take another lab class or upper div lab class. If you are a traditional premed major I'm sure you have upper divs that can be considered as biology classes that have a lab component to it. I took LS1 because i don't any other bio class with a lab other than LS2 and LS3. I took MCDB100 as my upper div bio class for schools like UCI and UC Davis that require upper div bio course and that didn't have a lab component. Essentially, I took LS1 for that one week 2 hour lab, which annoyed me a bit.
If you apply to UCSD, they don't even require lab for bio, physics, or chem and in their case, you won't have to take it and you won't even have to take the chem labs or physics labs either, but I think they're like one out of the three schools in the entire nation that do not require labs. All 100+ med schools require lab.
I have friends that did not take that class and go to stanford, northwestern, ucla, etc, so you don't need to take it in my opinion just watch out that you have all the one yr lab requirement fulfilled. With regards to the MCAT, you don't really need stuff from that class at all. I remember I had one question of all questions on the bio section when I took it that needed something from LS1 and as long as you review the main topics that are on the MCAT using like barron's or princeton review, you'll be fine. There's very little genetics on the MCAT, more so than stuff from LS1 but the main bulk of stuff comes from LS2 and 3.
