You work in a metabolic engineering laboratory and your principal investigator (pi) asked you to ferment escherichia coli atcc 8739 in three different am1 media. one medium contains 10% glucose as the sole carbon source, another medium contains 5% glucose + 5% lactose. the third medium contains 8% lactose. you prepared 900 ml of each medium and aliquoted 300 ml into three different fermentation jars (3 replicates for each fermentation condition). after setting up the fermentation at a controlled temperature (37°c) with automatic addition of 6m koh, you collected samples of the fermentation broth every 24 hours for four days. you also saved a sample for day zero after preparing the medium. at the end of the fourth day, you prepared the samples that you collected for high performance liquid chromatography (hplc) analysis. a few hours later, your hplc samples are ready for analysis. based on the peak areas from the hplc you calculated the concentrations of the sugars at day zero are as follows: glucose 10g/l (for the 10% glucose medium) 5 g/l glucose + 5 g/l lactose (for the 5% glucose + 5% lactose) 8 g/l lactose (for the 8% lactose medium) a) (1 pt) you notice that after 24 hours, the cells fermented in 5% glucose + 5% lactose used up all the lactose in the medium. however, there was still 4.5 g/l glucose in the medium. what kind of mutation (s) will lead to this? b) (1 pt) from the recitation, you know that e. coli can use lactose as a sole carbon source. however, you measured the optical density at 550 nm (d550 nm) of the cells fermented in 8% lactose medium and realized that the od550 nm is 0.01 - the same as the starting od even after 48 hours