Concept explainers
To review:
The standard free energy for the following reactions:
Introduction:
Gibbs free energy is the potential that can be used for the calculation of maximum reversible work that is performed at constant temperature and pressure. The phosphoryl group transfer potential of a compound can be defined as ameasure of the strength of attachment of a group to amolecule. It usually refers to the differences in the standard free energies of the molecule with and without the group.
Explanation of Solution
According to the standard reduction potentials (E°’) given in table 9.1, E°’ of some
Redox half-reaction | E°’ (in Volt or V) |
|
|
|
-0.32 |
|
+0.235 |
The calculation of standard free energy for the following reactions is described below:
For calculating the standard free energy, the number of electrons transferred needs to be balanced. For a reaction, the standard free energy can be calculated by using the Nernst equation
Where,
n is the number of electrons transferred,
F is Faraday’s constant, which is 96.15 kJ/V.mol (kilojoule per Volt. mole) and
∆E°’ is overall cell potential.
∆E°’ can be calculated by the following formula:
In the given case, E°’ of electron acceptor is +0.82 V and that of electron donor is -0.32 V.
Putting the values of n, F, and ∆E°’ in the Nernst equation:
Thus, the standard free energy of the reaction is
In the given case, E°’ of the electron acceptor is +0.82 V and that of the electron donor is -0.235 V.
For a reaction, the standard free energy can be calculated by using the Nernst equation.
Putting the value of n, F, and ∆ E°’ in the Nernst equation:
Thus, the standard free energy of the reaction is
Thus, it can be concluded that the standard free energy of
Want to see more full solutions like this?
Chapter 9 Solutions
Biochemistry: The Molecular Basis of Life
- This is a plot under standard conditions of free energy corresponding to a chemical reaction of A+B to C+D. What will happen if only C+D are present under standard temperature and pressure? Please explain why.arrow_forwardUnder standard conditions, will the following reaction proceed spontaneously as written?arrow_forwardThe plant toxin fluoroacetate (F-CH2COO−) is easily converted to fluorocitrate when an animal ingests the plant. The enzyme aconitase has a high affinity for the 2-fluorocitrate molecule. Consider the purpose of this enzyme and speculate as to why the reaction to produce isocitrate does not occur as planned. Why is fluoroacetate considered a poison? [Hint: Fluorine is more electronegative than oxygen.]arrow_forward
- The most important ion in biological systems is the____________________ ion.arrow_forwardThis is a picture of the catalysis of alcohol by ADH with an inhibitor binding as an aldehyde analog. I have two questions. First, what would the enzyme be classified as and why? Also, what would the steps of this mechanism be?arrow_forwardThe following question focuses on how the parameters regulating enzyme function might change, and how these might appear graphically on a Michaelis-Menten plot and a Lineweaver-Burke plot. Carbonic anhydrase is an enzyme that will convert CO2 and water into HCO3. CO2 + H20 > H+ + HCO3 There are many different isoforms of this enzyme. (see for instance http://en.wikipedia.org/wiki/Carbonic_anhydrase . Assume that one variant has a Km of 10 µM and a different variant has a Km of 100 µM. Draw on the same graph a typical Michaelis-Menton plot showing the alteration in the rate of carbonic anhydrase as the CO2 level is varied for the two different variants of enzyme, assuming the concentration of the enzyme (10 mM) in the test tube is kept constant. Assume that you have equal amounts of the two different variants of carbonic anhydrase in a number of test tubes and that the Vmax for both enzymes are the same. Be sure to label the axes. For the same conditions as above, draw a…arrow_forward
- The following question focuses on how the parameters regulating enzyme function might change, and how these might appear graphically on a Michaelis-Menten plot and a Lineweaver-Burke plot. Carbonic anhydrase is an enzyme that will convert CO2 and water into HCO3. CO2 + H20 > H+ + HCO3 There are many different isoforms of this enzyme. (see for instance http://en.wikipedia.org/wiki/Carbonic_anhydrase 1 Assume that one variant has a Km of 10 µM and a different variant has a Km of 100 µM. Draw on the same graph a typical Michaelis-Menton plot showing the alteration in the rate of carbonic anhydrase as the CO2 level is varied for the two different variants of enzyme, assuming the concentration of the enzyme (10 mM) in the test tube is kept constant. Assume that you have equal amounts of the two different variants of carbonic anhydrase in a number of test tubes and that the Vmax for both enzymes are the same. Be sure to label the axes. For the same conditions as above, draw a…arrow_forwardThe following question focuses on how the parameters regulating enzyme function might change, and how these might appear graphically on a Michaelis-Menten plot and a Lineweaver-Burke plot. Carbonic anhydrase is an enzyme that will convert CO2 and water into HCO3. CO2 + H20 > H+ + HCO3 There are many different isoforms of this enzyme. (see for instance http://en.wikipedia.org/wiki/Carbonic_anhydrase . Imidazol is a competitive inhibitor of carbonic anhydrase. It is effective at an alkaline (high) pH; in lower (more acidic) pH, it no longer inhibits the enzyme. Draw on a separate graph a Lineweaver-Burke plot for the effects of this compound at high pH and low pH. Be sure to label the axes and put in sample data points.arrow_forwardQuestion 2 of 13 Fill in the blanks: Write C if only statement A is correct, H if only statement B is correct, E if both statements are correct, M if both statements are incorrect. A. The Michaelis-Menten plot shows that initially, the increase in the reaction velocity is relatively fast. B. Then after sometime, the change in the reaction velocity slows down and tapers off to a certain limit.arrow_forward
- Most of the enzyme reactions followed the mathematical kinetic plots suggested by Michaelis-Menten plots: Give the Michaelis-Menten equation of an enzyme reaction and draw the Michaelis-Menten plot of [S] versus V0.arrow_forwardWith the Boltzmann distribution, the population of electrons that correspond to the en- ergy levels of a metal cannot be obtained. Why?.arrow_forwardWhat three types of reactions don’t fit in the simple Michaelis-Menten modelarrow_forward
- BiochemistryBiochemistryISBN:9781319114671Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.Publisher:W. H. FreemanLehninger Principles of BiochemistryBiochemistryISBN:9781464126116Author:David L. Nelson, Michael M. CoxPublisher:W. H. FreemanFundamentals of Biochemistry: Life at the Molecul...BiochemistryISBN:9781118918401Author:Donald Voet, Judith G. Voet, Charlotte W. PrattPublisher:WILEY
- BiochemistryBiochemistryISBN:9781305961135Author:Mary K. Campbell, Shawn O. Farrell, Owen M. McDougalPublisher:Cengage LearningBiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage LearningFundamentals of General, Organic, and Biological ...BiochemistryISBN:9780134015187Author:John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. PetersonPublisher:PEARSON