Electron Transport Chain
Here’s a flashcard set designed to help you learn the Electron Transport Chain (ETC) from scratch. Each card builds on the previous one to create a clear understanding of the process.
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### Flashcard 1: What is the Electron Transport Chain (ETC)?
- Front: What is the Electron Transport Chain (ETC)?
- Back: The ETC is a series of protein complexes and molecules in the inner mitochondrial membrane that transfers electrons to generate ATP, the cell's energy currency.
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### Flashcard 2: Where does the ETC occur?
- Front: Where does the ETC occur?
- Back: In the inner mitochondrial membrane of eukaryotic cells (or the plasma membrane of prokaryotic cells).
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### Flashcard 3: What is the main purpose of the ETC?
- Front: What is the main purpose of the ETC?
- Back: To create a proton gradient across the inner mitochondrial membrane, which drives ATP synthesis via ATP synthase.
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### Flashcard 4: What molecules donate electrons to the ETC?
- Front: What molecules donate electrons to the ETC?
- **Back:** NADH and FADH₂, which are produced during glycolysis, the citric acid cycle, and other metabolic pathways.
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### Flashcard 5: What are the four main protein complexes in the ETC?
- Front: What are the four main protein complexes in the ETC?
- Back:
1. Complex I (NADH dehydrogenase)
2. Complex II (Succinate dehydrogenase)
3. Complex III (Cytochrome bc₁ complex)
4. Complex IV (Cytochrome c oxidase)
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### Flashcard 6: What happens at Complex I?
- Front: What happens at Complex I?
- Back:
- NADH donates electrons to Complex I.
- Electrons are passed to ubiquinone (CoQ), and protons (H⁺) are pumped into the intermembrane space.
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### Flashcard 7: What happens at Complex II?
- Front: What happens at Complex II?
- Back:
- FADH₂ donates electrons to Complex II.
- Electrons are passed to ubiquinone (CoQ), but no protons are pumped at this step.
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### Flashcard 8: What is the role of ubiquinone (CoQ)?
- Front: What is the role of ubiquinone (CoQ)?
- Back: CoQ shuttles electrons from Complexes I and II to Complex III.
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### Flashcard 9: What happens at Complex III?
- Front: What happens at Complex III?
- Back:
- Electrons are transferred from CoQ to cytochrome c.
- Protons are pumped into the intermembrane space.
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### Flashcard 10: What is the role of cytochrome c?
- Front: What is the role of cytochrome c?
- Back: Cytochrome c shuttles electrons from Complex III to Complex IV.
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### Flashcard 11: What happens at Complex IV?
- Front: What happens at Complex IV?
- Back:
- Electrons are transferred to oxygen (O₂), forming water (H₂O).
- Protons are pumped into the intermembrane space.
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### Flashcard 12: What is the final electron acceptor in the ETC?
- Front: What is the final electron acceptor in the ETC?
- **Back:** Oxygen (O₂), which combines with electrons and protons to form water (H₂O).
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### Flashcard 13: What is the proton gradient?
- Front: What is the proton gradient?
- Back: The accumulation of protons (H⁺) in the intermembrane space creates a gradient, storing potential energy used to make ATP.
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### Flashcard 14: What is ATP synthase?
- Front: What is ATP synthase?
- Back: An enzyme that uses the proton gradient to phosphorylate ADP, producing ATP.
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### Flashcard 15: How many ATP molecules are produced per NADH and FADH₂?
- Front: How many ATP molecules are produced per NADH and FADH₂?
- Back:
- NADH produces ~2.5 ATP.
- FADH₂ produces ~1.5 ATP.
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### Flashcard 16: What is oxidative phosphorylation?
- Front: What is oxidative phosphorylation?
- Back: The process of ATP production driven by the ETC and ATP synthase, using energy from electron transfer and the proton gradient.
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### Flashcard 17: What happens if oxygen is not available?
- Front: What happens if oxygen is not available?
- Back: The ETC stops because oxygen is the final electron acceptor. This halts ATP production and leads to fermentation or cell death.
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### Flashcard 18: Summary of the ETC
- Front: Summarize the ETC in one sentence.
- Back: The ETC uses electrons from NADH and FADH₂ to create a proton gradient, which drives ATP synthesis via ATP synthase, with oxygen as the final electron acceptor.
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This set should give you a solid foundation to understand the ETC! Review the cards in order, and once you’re comfortable, shuffle them to test your knowledge.