Question

1) Vibrio alginolycticus is a marine bacterium whose energetics is based on sodium gradients. This microbe grows in an environment containing 0.5 M Na+ at pH 5.6. Consider if the internal pH of this organism is 7.6, its membrane potential is -120 mV and has a Na+/H+ antiport. This bacterium translocates H+ that are used to form 3 ATP molecules. In addition, translocation of one mole of the nonmetabolizable and non-toxic leucine analogue, norleucine, against a concentration gradient is energetically coupled to the translocation of one mole of H⁺. Suppose this bacterium is growing in seawater containing 1mM norleucine. Calculate the following: (20 pts)

A) Proton motive force

B) Internal norleucine concentration

C) Electromotive force

D) Phosphorylation potential

Answer 1