And the insulin receptor actually is a diamond that consists of two identical chains, one chain and a second identical chain. And each one of these chains themselves consists of two individual units. We have the alpha unit shown here in purple, and this beta unit shown here in pink. Now, the alpha unit is attached onto the beta unit by a disulfide bridge shown here. So we have one bridge shown here and another bridge shown on that adjacent identical chain. Now, what exactly is the function of the alpha and the beta units?