Which of the following is not a problem associated with low yields expressed in yeast? a. Proteins are not getting secreted into the medium. b. Yeast has no known naturally occurring plasmids from which to construct expression vectors. c. Expression plasmids are lost in large occurs batch cultures of yeast. d. Too much modification of the protein (ie., glycosylation). e. None of the above is a problem associated with low yield. What is a bacmid? a. a virus to infect bacterial cells. b. a recombinant protein from bacteria that is expressed in insect cells c. a shuttle vector that replicates as a plasmid in E. coli and virus is in insect cells. d. a general term for bacterial expression vectors. e. none of the above Are insect cells fully able to glycosylate foreign proteins? a. yes b. no c. partially, only up to the addition of mannose d. uncertain, has never been experimentally tested e. none of the above Which of the following is not used as a selectable marker to maintain mammalian shuttle vectors within mammalian cells? a. genetecin b. fungicides c. DHFR gene d. glutamine synthetase gene e. all of the above 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.