Question

1.) a key reaction in glycolysis is the isomerization of dihydroxyacetone into gylceraldehyde-3-phosphate. dhap<> G-3-P Delta G = 7.5 kj/mol

a.) whis is favored in this equilibrium, DHAP OR G-3-P?

B.) Calculate the equilibrium constant for the reaction at 25 degrees C.

C.) in the cell depletion of G-3-P makes the reaction proceed. what will delta G be if the temperature concentration of G-3-P is always kept 1/100 of the concentration of DHAP at a temp of 37 degrees C?

Answer 1

simple biochemical reaction:

the interconversion of the compounds glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP).

This reaction, which occurs during the breakdown of glucose, is catalyzed by the enzyme triosephosphate isomerase:

The equilibrium constant for this reaction under standard conditions is

Thus the ratio of the concentrations of G3P and DHAP is 1:22.2 when the reaction reaches equilibrium. In practice, one measures the concentrations of reactants and products after a reaction has reached equilibrium, and uses these values to calculate the equilibrium constant.

In the presence of an enzyme or other catalyst, the reaction rate may increase, but the final ratio of product to reactant will always be the same.

The magnitude of the equilibrium constant has no bearing on the rate of the reaction or on whether the reaction will take place at all under normal conditions.

Despite the large equilibrium constant for the conversion of G3P to DHAP, for example, so much energy is required to rearrange the bonds that no detectable reaction actually occurs in an aqueous solution in the absence of an enzyme or other catalyst.

When a reaction involves a single reactant and a single product, the ratio of the product concentration to reactant concentration at equilibrium is equal to the equilibrium constant Keq and is independent of the initial concentrations.

When a reaction involves multiple reactants and/or products, the equilibrium concentration of any one product or reactant depends on the initial concentrations of all reactants and products as well as on the equilibrium constant.