Which of the following statements about insulin manufacturing is not true? a. Diabetics used to have to inject themselves had been purified from the pancreas of either cows or pigs. b. Bacteria are able to express and process this peptide into insulin. c. Natural insulin forms hexamers, which causes the hormone to clump. d. A proline converted to an aspartic acid keeps insulin from clumping. e. Recombinant insulin is expressed as two mini-genes. The recently discovered autotransporter proteins of bacteria: a. Transport themselves without using any secretory system. b. Are able to cross membranes because they are very small proteins. c. Require the Type III secretory system to cross the bacterial outer membrane. d. Require the BAM complex to cross the bacterial outer membrane. e. Rely on attached lipid molecules to function.