Applying to bachelors AND integrated masters?

I'm looking to apply to biological sciences courses, and many of the unis I've looked at offer the course as just a 3 years bachelor degree or as a 4 year integrated masters, but with the integrated masters courses generally having high entry requirements by a grade or so. My question is is it worth applying to both the bachelors and integrated masters course incase I don't quite get the grades for the MSc course, or is it standard practice for universities to transfer a masters offer to a bachelors if I was to reach the grades needed for a BSc? Or is it easy enough to play it safe, apply for just the BSc so I'm not using up 2 of my choices on practically the same course, and then try move onto the integrated masters pathway once at uni?
I've been mainly looking at Leeds, Sheffield, Durham and Manchester