Biochemistry: Concepts and Connections (2nd Edition)
2nd Edition
ISBN: 9780134641621
Author: Dean R. Appling, Spencer J. Anthony-Cahill, Christopher K. Mathews
Publisher: PEARSON
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Chapter 14, Problem 2P
When pure reduced cytochrome c is added to carefully prepared mitochondria along with ADP Pi, antimycin A, and oxygen, the cytochrome c becomes oxidized, and ATP is formed, with a P/O ratio approaching 1.0.
- Indicate the probable flow of electrons in this system.
- Why was antimycin A added?
- What does this experiment tell you about the location of coupling sites for oxidative phosphorylation?
- Write a balanced equation for the overall reaction (including cyt c oxidation and ATP synthesis).
- Calculate ΔGO' for the above reaction, using E'o values from Table 14.1 and a ΔGO' value for ATP hydrolysis of -32.2 kJ / mol.
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When pure reduced cytochrome c is added to carefully prepared mito-
chondria along with ADP, P, antimycin A, and oxygen, the cytochrome c
becomes oxidized, and ATP is formed, with a P/O ratio approaching 1. Why
was antimycin A added, and what does this experiment tell you about the
location of coupling sites?
When pure reduced cytochrome c is added to carefully prepared
mitochondria along with ADP, P, antimycin A, and oxygen, the
cytochrome c becomes oxidized, and ATP is formed, with a P/o
ratio approaching 1.0.
(a) Indicate the probable flow of electrons in this system.
(b) Why was antimycin A added?
(c) What does this experiment tell you about the location of cou-
pling sites for oxidative phosphorylation?
(d) Write a balanced equation for the overall reaction (including cyt
c oxidation and ATP synthesis).
The reduction potentials of iron in each of the cytochromes in the electron transport complexesvary from 0.The reduction potentials of iron in each of the cytochromes in the electron transport complexes vary from 0.1 V to 0.39 V. Explain why these different values are necessary for the operation of this process
Chapter 14 Solutions
Biochemistry: Concepts and Connections (2nd Edition)
Ch. 14 - Prob. 1PCh. 14 - When pure reduced cytochrome c is added to...Ch. 14 - Freshly prepared mitochondria were incubated with...Ch. 14 - Prob. 4PCh. 14 - Prob. 5PCh. 14 - Prob. 6PCh. 14 - Intramitochondrial ATP concentrations are about 5...Ch. 14 - Prob. 8PCh. 14 - Prob. 9PCh. 14 - Years ago there was interest in using uncouplers...
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- Citrate and isocitrate are interconverted via the enzyme aconitase: The standard free energy change for this reaction is +6.7 kJ/mol. In my pet llama's mitochondria, the free energy change was measured to be +0.8 kJ/mol. (No llamas were harmed in this experiment!) a. Calculate the [isocitrate]/[citrate] ratio in these mitochondria. b. If [isocitrate] =0.03 mM, what is [citrate]?arrow_forwardTwo biochemistry students are about to usemitochondria isolated from rat liver for an experiment on oxidative phosphorylation. The directions for the experiment specifyaddition of purified cytochrome c from any source to the reactionmixture. Why is the added cytochrome c needed? Why does thesource not have to be the same as that of the mitochondria?arrow_forwardWhat is the free energy change for generating the electrical imbalance of protons in respiring mitochondria in culture, where Δψ is 150 mV? (Express your answer in kJ/mol using 3 significant figures.)arrow_forward
- The AG of the reaction C6H12O6 + 60₂ --> 6CO₂ + 6H₂O is -686 kcal/mol glucose oxidized. The AG of the reaction ADP + P₁ --> ATP + H₂O is + 7.3 kcal/mol ATP synthesized. The oxidation of glucose can be coupled to the synthesis of ATP. If the coupling is 50% efficient, how many molecules of ATP can be synthesized per molecule of glucose oxidized? Round your answer to the nearest whole number.arrow_forwardThe electron-transport chain consists of a number of multi protein complexes, which work in conjunction to pass electrons from an electron carrier, such as NADH, to O2. What is the role of these complexes in ATP synthesis? It has been demonstrated that respiration supercomplexes contain all the protein components necessary for respiration. Why is this beneficial for ATP synthesis, and what is one way that the existence of super complexes has been demonstrated experimentally? Coenzyme Q (CoQ) is not a protein, but a small, hydrophobic molecule. Why is it important for the functioning of the electron transport chain that CoQ is a hydrophobic molecule?arrow_forwardCoupled reactions occur where a nonspontaneous reaction is enabled by coupling it to a spontaneous reaction. This approach is common in biological settings. Determine if ATP could be generated by this biochemical reaction. You have calculated that cell potential is +0.637V. An example of a coupled reaction is the first step of glycolysis, the phosphorylation of glucose to form glucose-6-phosphate shown below. The net ∆Gº for this reaction isarrow_forward
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