They aren't intrinsically inferior - the insinuation that they are is because most are ex-polytechnics, very new, or offer more vocational courses, and this is sufficient for some people to trust them less than the older universities. They also tend to have lower entry requirements because of this.
It would be disingenuous to tell you that they are regarded in the same way. However unfair it is, if you want to go into an area like academia (and to a lesser extent general research), people will judge you on the name of your university, and a Russel group or equivalent university could make the difference between getting a job or not. I'll probably get negged for this, but with Biology I have to advise you to try to go for the highest regarded university you can, because to do anything else would be unfair.
Please understand I have nothing against these newer universities - my Dad lectures at one, and he does a good job, and he loves it. However, the harsh reality is that the name matters.