Question

this graph uses the letters a and b to indicate reactants such as an amino acid (a) and a growing protein (b). here the reaction would be the formation of a peptide bond that adds a to the growing protein. according to this graph, are reactions like this spontaneous or nonspontaneous?
○ spontaneous
○ nonspontaneous

Explanation:

Step1: Recall the definition of spontaneous and non - spontaneous reactions

A spontaneous reaction is one that occurs without the input of external energy and has a negative change in free energy ($\Delta G<0$, products have lower free energy than reactants). A non - spontaneous reaction requires an input of energy and has a positive change in free energy ($\Delta G > 0$, products have higher free energy than reactants).

Step2: Analyze the graph

In the graph, the free energy of the products ($A - B$) is higher than the free energy of the reactants ($A + B$). So, $\Delta G=G_{products}-G_{reactants}>0$.

Answer:

Nonspontaneous