26 Questions
In which direction do electrons flow in the electron transport chain?
From carriers with more negative E0 to more positive E0
What is the number of ATP molecules generated per NADH molecule using oxygen as the terminal electron acceptor?
3 ATP
What is the primary function of the proton gradient established during oxidative phosphorylation?
To generate ATP through chemiosmosis
What is the mechanism by which ATP is generated from the energy released in the electron transport chain?
Oxidative phosphorylation
Which component of the F1Fo ATP Synthase is responsible for proton translocation?
Fo subunit
Which structure is responsible for generating ATP from the proton motive force?
F1Fo ATP synthase
What is the process by which the energy from the proton motive force is used to drive ATP synthesis?
Chemiosmosis
What is the result of proton movement back across the membrane during chemiosmosis?
ATP synthesis
Which of the following is NOT a component of the bacterial electron transport chain?
Acetyl-CoA synthase
In which direction do protons flow during the electron transport chain?
From the mitochondrial membrane to the intermembrane space
What is the direction of proton movement during the electron transport chain?
Out of the mitochondrial matrix
What is the net gain of ATP molecules per glucose molecule in cellular respiration?
36-38 ATP
What is the function of the c subunit ring in the F1Fo ATP Synthase?
To rotate during proton translocation
Which of the following is NOT a component of the electron transport chain?
Glyceraldehyde-3-phosphate
What is the electron transport chain responsible for generating?
A proton gradient
Where is the proton motive force generated during oxidative phosphorylation?
Across the mitochondrial inner membrane
What is the function of the F1 subunit of the F1Fo ATP Synthase?
To catalyze ATP synthesis
What is the result of the chemiosmotic hypothesis?
The establishment of a proton gradient
What is the final product of denitrification in anaerobic respiration?
Nitrogen gas (N2)
What is the purpose of the proton motive force in oxidative phosphorylation?
To drive ATP synthesis through the F1Fo ATP synthase
Which of the following is NOT a component of the electron transport chain in bacteria?
F1Fo ATP synthase
What is the function of the rotating ring of c subunits in the F1Fo ATP synthase?
To drive ATP synthesis
What is the basis of the Nitrite Strip Test for urinary tract infections?
Nitrate reduction to nitrite
How many ATP molecules are generated per NADH using oxygen as the terminal electron acceptor?
3
In which membrane is the electron transport chain found in bacteria?
Plasma membrane
What is the chemiosmotic hypothesis?
Energy released during electron transport is used to establish a proton gradient
Study Notes
Oxidative Phosphorylation
- Energy released during electron transport is used to establish a proton gradient and charge difference across the membrane.
- Proton motive force (PMF) drives ATP synthesis through the F1Fo ATP synthase.
- F1Fo ATP synthase is a multiprotein complex that uses proton movement to catalyze ATP synthesis.
F1Fo ATP Synthase
- In bacterial F1Fo ATP synthase, the proton channel is in the F0 subunit.
- Rotating ring of c subunits drives ATP synthesis.
Electron Transport Chain
- Electrons from NADH and FADH2 generated by the oxidation of organic substrates are transferred through a series of membrane-bound electron carriers.
- Electron carriers include cytochromes and quinones, and are found in the mitochondrial membrane in Eukarya and plasma membrane in Bacteria and Archaea.
- Electrons flow from carriers with more negative E0 to more positive E0, releasing energy used to make ATP by oxidative phosphorylation.
- 3 ATP can be generated per NADH using O2 as the terminal electron acceptor.
Anaerobic Respiration Example
- Denitrification: Nitrate (NO3-) as terminal electron acceptor, reduced to nitrogen gas (N2).
- Paracoccus denitrificans: Facultative anaerobe in soil, depletes soil N, lower crop yield.
- Escherichia coli: Facultative anaerobe, can use Nitrate as e- acceptor, Nitrate first reduced to Nitrite, basis of Nitrite Strip Test - diagnostic for Urinary Tract Infections (UTI).
TCA Cycle and Electron Transport
- Pyruvate is oxidized to form Acetyl CoA, releasing a CO2 and producing a high-energy thioester bond.
- TCA cycle produces more oxidations, forming NADH and FADH2.
- Net yield of 2 ATP molecules synthesized directly from the oxidation of glucose.
- Most ATP is made when NADH and FADH2 are oxidized in electron transport chains.
This quiz covers the process of oxidative phosphorylation, including the chemiosmotic hypothesis and how proton motive force drives ATP synthesis.
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