I concur that the best information will be found mater’s and doctoral program websites - both by checking their prerequisites and their courses of study.
I’m thinking that chemistry would be better as a minor than biology. Bio would be studying what we know about species on Earth, but there’s no way of knowing if life in outer space will have any relationship to the biology of life on Earth. Chemistry will get you down to a more basic level. Biochemistry or Evolutionary Biology would have more relevance than straight Biology.