https://pages.htgaa.org/2026b/paulina-liceaga/week-03-hw-cell-free/index.htmlA. COMPARE CELL-FREE REACTION COMPOSITIONS A1. Why does the concentration of potassium glutamate and magnesium glutamate differ between compositions? Which is more sensitive? The concentrations differ because each formulation was optimized for its own conditions. The lysate strain and preparation method change how much Mg²⁺ and K⁺ the extract already carries over, and the energy system matters too. Jewett & Swartz (2004) had to lower Mg²⁺ when switching from PEP to pyruvate, because PEP binds Mg²⁺ more tightly (11.3 mM total in Cytomim vs about 23 mM in PANOx-SP). Olsen et al. (2026) likewise re-tuned Mg²⁺ and phosphate for each new lysate batch. The two ions also do different jobs. K⁺ is the main cation that sets ionic strength, so it is needed at roughly 80-362 mM across formulations. Mg²⁺ is a cofactor for ribosomes and polymerases, needed at about 8-10 mM.Hugoen