Answered Dec 20, 2017
Thanks for the A2A.
On YouTube (or the internet in general), there isn’t just one single resource that I can recommend.
However, I have a page of links for science students (of all levels) at:
Please excuse the formatting, as I still need to work on that. However, these are the best links that I have found so far, and are somewhat categorised by field of study, with a few comments.
This page will improve in the near future, but generally, these are the links that I have appreciated, for biology, biochemistry, chemistry, mathematics, and , of course, microbiology.