Question

In a biochemistry lab, a researcher is closely examining a microbial chemical reaction. During the experiment, he determines that the value of ∆G°′ is approximately +38 kJ mol−1. Explain what this value means about the reaction being examined.

Answer 1

The +38 kJ mol−1 value for ΔG°′ in a microbial chemical reaction signifies that the reaction is endergonic, requiring an input of energy to proceed, and that at equilibrium, the concentration of reactants will be greater than that of products.

Step-by-step explanation:

The value of ΔG°′ being approximately +38 kJ mol−1 indicates that the microbial chemical reaction in question is endergonic. This means that the reaction absorbs free energy from its surroundings rather than releasing it. Under standard conditions, which include a pH of 7.0, a temperature of 25 degrees Celsius, and 1 atm pressure, an endergonic reaction will not proceed spontaneously because it requires an input of energy. The positive ΔG°′ value also suggests that at equilibrium, the concentrations of reactants will be higher than the concentrations of products. Thus, for the reaction to proceed, external energy must be provided or it must be coupled with an exergonic reaction, which would supply the necessary free energy.

It is important to note that these conditions represent a standardized set of conditions that may differ from actual cellular conditions where reactions take place. Variations in pH, temperature, and pressure within the cell can alter the actual free energy change (ΔG) of a reaction.