What function does an internal ribosomal entry site serve? a. as a way to translate polycistronic mRNA in eukaryotes that carries the genes for multiple subunits of a protein b. as a protease cleavage site in between two proteins expressed on one transcript c. as a way to control the expression of two different proteins d. as a way to differentially express two proteins on the same transcript e. none of the above Which factor affects which protein expression system to utilize? a. Cost b. ability to glycosylate or fold proteins c. speed d. government regulations e. all of the above Which of the following is not involved in the manufacturing of insulin? a. endopeptidases b. carboxypeptidase H c. signal peptidase d. phosphodiesterase 5 e. All of the above are involved in the manufacturing of insulin.