And so this antigen or this antibody will bind to the antigen, the protein found in the second band. So the monochrome antibody is added onto the polymer sheet containing the separated protein mixture and it only binds onto the antigen, onto the protein that we actually are interested in. Now, in step number five, we synthesize yet another antibody and now we synthesize an antibody that is radioactively labeled. And what that allows us to do in the final step is to visualize exactly where that protein is. Now, the antibody that we want to synthesize the second time around, this antibody in step number five is known as the secondary antibody. And the secondary antibody is made so that it binds onto that primary antibody that we form in step one.