Untitled Flashcards Set

### Exam Topics Highlighted by the Professor (Fermentation, Cellular Respiration, and Mitochondria)

This transcript covers key topics related to fermentation, cellular respiration, and mitochondrial function, with multiple references to exam-relevant material. Below are the topics that the professor specifically mentioned will be on the exam, along with key takeaways for each.

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### 1. Fermentation & Its Role in Energy Production

- What to remember:

- Fermentation is an anaerobic process that occurs when oxygen is unavailable.

- It produces lactate (in animals) or ethanol & CO₂ (in yeast) as end products.

- It is an inefficient process—**only 7% of glucose's energy is harvested**.

- Despite its inefficiency, it is useful because it can generate ATP quickly.

- Cancer cells rely on fermentation to rapidly produce energy, even though it is inefficient.

- Exam Tip:

- Be able to identify what fermentation does and does not produce (e.g., carbon dioxide, NAD+, ethanol, lactate).

- Example question format:

- Which of the following is NOT an end product of fermentation?

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### 2. Cellular Respiration vs. Fermentation

- What to remember:

- Fermentation only partially oxidizes glucose, leaving energy trapped in lactate or ethanol.

- Aerobic respiration extracts much more energy (up to 38 ATP per glucose).

- Cellular respiration requires an external electron acceptor to fully oxidize substrates.

- Oxygen is the final electron acceptor in aerobic respiration.

- Exam Tip:

- Be able to differentiate fermentation from aerobic respiration.

- Example question format:

- What is the primary reason aerobic respiration is more efficient than fermentation?

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### 3. The Electron Transport Chain & Oxygen as the Final Electron Acceptor

- What to remember:

- Cellular respiration involves glycolysis, citric acid cycle, and electron transport chain (ETC).

- ETC transfers electrons to oxygen, allowing full oxidation of glucose.

- Anaerobic respiration uses different final electron acceptors, but oxygen is the most efficient.

- Exam Tip:

- Understand why oxygen is the best electron acceptor (it is highly electronegative).

- Example question format:

- Which of the following is the final electron acceptor in aerobic respiration?

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### 4. Citric Acid Cycle (Krebs Cycle) & Its Role in Energy Extraction

- What to remember:

- The citric acid cycle occurs in the mitochondrial matrix.

- It completely oxidizes acetyl-CoA into CO₂.

- Produces:

- NADH & FADH₂ (electron carriers)

- A small amount of ATP/GTP

- Most energy is stored in NADH & FADH₂, which carry electrons to the ETC.

- Exam Tip:

- Know the inputs and outputs of the citric acid cycle.

- Example question format:

- Which of the following is NOT a product of the citric acid cycle?

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### 5. Pyruvate Processing & Entry into the Citric Acid Cycle

- What to remember:

- Pyruvate (from glycolysis) is converted into acetyl-CoA before entering the citric acid cycle.

- This is done via pyruvate dehydrogenase, which removes CO₂ and produces NADH.

- This step links glycolysis to the citric acid cycle.

- Exam Tip:

- Be able to identify what enzyme converts pyruvate to acetyl-CoA.

- Example question format:

- What is the enzyme responsible for converting pyruvate into acetyl-CoA?

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### 6. Mitochondrial Structure & Function

- What to remember:

- The mitochondrion has two membranes (inner & outer).

- The inner membrane contains the electron transport chain and ATP synthase.

- Cristae (folds in the inner membrane) increase surface area for ATP production.

- The mitochondrial matrix contains enzymes for the citric acid cycle.

- Mitochondria have their own DNA and can divide independently.

- Exam Tip:

- Understand the function of different mitochondrial compartments.

- Example question format:

- Which part of the mitochondrion contains the enzymes for the citric acid cycle?

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### 7. ATP Production & Oxidative Phosphorylation

- What to remember:

- ATP is primarily produced by oxidative phosphorylation.

- Proton gradients (H+ gradients) drive ATP synthesis via ATP synthase.

- The electron transport chain pumps protons into the intermembrane space, creating a gradient.

- Oxygen is the final electron acceptor, forming water.

- Exam Tip:

- Be able to describe how ATP is generated from the proton gradient.

- Example question format:

- How does ATP synthase generate ATP?

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### 8. Enzyme Regulation & Feedback Inhibition in the Citric Acid Cycle

- What to remember:

- The citric acid cycle is regulated by:

- ATP levels (high ATP inhibits the cycle)

- NADH levels (high NADH inhibits key enzymes)

- Key enzymes regulated by allosteric inhibition:

- Pyruvate dehydrogenase

- Isocitrate dehydrogenase

- α-ketoglutarate dehydrogenase

- Succinate dehydrogenase

- Exam Tip:

- Know which enzymes are regulated and how feedback inhibition works.

- Example question format:

- Which enzyme in the citric acid cycle is inhibited by high levels of NADH?

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### 9. Beta-Oxidation of Fatty Acids

- What to remember:

- Fatty acids are broken down via beta-oxidation into acetyl-CoA.

- This process provides more energy per gram than carbohydrates.

- Fat is the primary long-term energy store because it is highly reduced.

- Exam Tip:

- Be able to explain beta-oxidation and its importance.

- Example question format:

- What process breaks down fatty acids into acetyl-CoA?

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### 10. Protein Catabolism & Energy Production

- What to remember:

- Proteins are broken down into amino acids.

- Amino acids can be used for energy by converting them into citric acid cycle intermediates.

- Proteins are used for energy only when necessary (e.g., during starvation).

- Exam Tip:

- Understand why protein is not the preferred energy source.

- Example question format:

- Why is protein catabolism a last resort for energy production?

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### 11. Electron Transport Chain & Electron Carriers

- What to remember:

- Electron carriers (e.g., NADH, FADH₂) pass electrons through the ETC.

- The ETC is located in the inner mitochondrial membrane.

- Electrons are passed through a series of protein complexes to oxygen.

- This process creates a proton gradient, which drives ATP synthesis.

- Exam Tip:

- Know the major electron carriers in the ETC.

- Example question format:

- Which molecule serves as the final electron acceptor in the ETC?

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### Final Takeaways for Exam Prep

1. Fermentation vs. aerobic respiration (efficiency, electron acceptors).

2. Citric acid cycle outputs (ATP, NADH, FADH₂, CO₂).

3. Mitochondrial structure & function (cristae, inner membrane, matrix).

4. Electron transport chain & oxidative phosphorylation.

5. Regulation of the citric acid cycle (allosteric inhibition by ATP, NADH).

6. Beta-oxidation of fatty acids (acetyl-CoA production, high energy yield).

7. Protein metabolism (last resort energy source).

8. Key electron carriers (NADH, FADH₂).

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### Suggested Study Approach

- Make flashcards for important enzymes, products, and processes.

- Draw diagrams of cellular respiration pathways.

- Practice explaining concepts aloud (teaching someone else helps retention).

- Answer practice questions based on the example formats provided.

Let me know if you need further explanations or extra study guides! 🚀