for what values of delta G would the following reactions have?
(no numerical value, just positive or negative)
a. ATP -> ADP + P(subscript i)
b. ADP + P(subscript i) -> ATP
c. Glucose -> Pyruvate
d. glocose -> oxygen
e. starch -> glucose
To determine the sign of ΔG (change in Gibbs free energy) for each reaction, we need to consider whether the reaction is exergonic (spontaneous, releasing energy) or endergonic (non-spontaneous, requiring energy input).
The equation for ΔG for a reaction can be given as follows:
ΔG = ΔH - TΔS
where:
ΔG = change in Gibbs free energy
ΔH = change in enthalpy
T = temperature in Kelvin
ΔS = change in entropy
If ΔG is negative, it indicates an exergonic reaction, meaning energy is released. If ΔG is positive, it indicates an endergonic reaction, meaning energy is required.
Let's analyze each reaction:
a. ATP -> ADP + Pi
Breaking down ATP into ADP (adenosine diphosphate) and Pi (inorganic phosphate) releases energy. Therefore, this reaction is exergonic and ΔG is negative.
b. ADP + Pi -> ATP
Synthesizing ATP from ADP and Pi requires energy input. Thus, this reaction is endergonic and ΔG is positive.
c. Glucose -> Pyruvate
The conversion of glucose to pyruvate typically occurs during glycolysis. Since glucose is broken down and energy is released, this reaction is exergonic and ΔG is negative.
d. Glucose -> Oxygen
The reaction of glucose with oxygen typically involves complete oxidation during cellular respiration. This reaction releases a significant amount of energy, making it exergonic and ΔG negative.
e. Starch -> Glucose
Breaking down starch into glucose subunits requires enzymatic hydrolysis, which involves energy input. As a result, this reaction is endergonic and ΔG is positive.
Please note that while we can determine the sign of ΔG, it does not provide quantitative information about the magnitude of the energy change. To obtain specific values, the corresponding enthalpy and entropy changes (ΔH and ΔS) would need to be known.