 We design the proteins we want and we insert the DNA sequence of the proteins into bacteria. We take those bacteria with the DNA in them and we put them into a nice warm, happy environment. We let them grow and grow and grow and then we use a specific chemical that we add in that tells them, okay, make our protein out. They make our protein. And then once there's enough of the bacteria, we chill them so they stop growing and we purify them so we can get our protein out and make sure that there's nothing else in there.