1. Chinese Hamster Ovary (CHO) cells are used to manufacture Enbrel, a top selling pharmaceutical, in a reactor. The stream exiting the reactor flows at 100.0 g/hr and contains 5.000% by mass of Enbrel, 6.700% by mass CHO cells, and the balance cell culture medium. This mixture is fed into a separator to recover the product and recycle cells and medium to the reactor. Assuming that the feed to the reactor consists of cell culture medium, all of the cells exiting to the separator are recycled to the reactor, and that 99.90% of Enbrel and 5.000% of the cell culture medium is recovered in the product stream: a. What is Enbrel? What is its structure? What does it do? b. Please describe the CHO system. Why is it used in pharmaceutical production instead of less complex systems like yeast and bacteria? c. Diagram this problem. d. Perform a degree of freedom analysis on every unit except the reactor, form a plan of attack, and solve this problem. Note that although there is a reactor, we do not need to know the details of reaction as the problem can be solved without evaluating this unit. (simple recycle)