I'm not sure about their policy on transfers, but Level II in Life Science as a McMaster student requires you to have a 6.0 McMaster Average (C+ average). You should contact someone on
this site as a reference to be sure.
Also, where did they come up with 4.3 as a scale?
If their scaling is that low, then they might as well go with the 4.0 standard. At least McMaster's 12.0 is more understandable, going down by an integer every grade point interval.