Question: The plot of novelist Rose Darkly’s current work in progress, Despair at the Heat Death Cafe, revolves around the production of the “energy currency” of the cells of an alien species. Rather than have her aliens’ cells use ATP as the compound that links catabolism and anabolism, Ms. Darkly wants to have them use one of three compounds: phosphoenolpyruvate, glucose-6-phosphate, or ADP. In the hope of making her novel as scientifically correct as possible, she’s called you in for advice on which of these three compounds is the most reasonable choice for the role.

Question: What is one advantage of using E. coli for genetic engineering? One disadvantage?