Cellular Respiration

Q1: What is the main purpose of cellular respiration?
A: To convert energy in glucose into usable ATP for cellular work.

Q2: What is the overall equation for aerobic cellular respiration?
A: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ~32 ATP

Q3: What are the four stages of aerobic respiration?
A: Glycolysis, pyruvate oxidation, citric acid cycle, and oxidative phosphorylation.

Q4: Where does glycolysis occur?
A: In the cytoplasm of the cell.

Q5: What are the outputs of glycolysis?
A: 2 pyruvate, 2 ATP, and 2 NADH.

Q6: What happens during pyruvate oxidation?
A: Each pyruvate is converted into Acetyl-CoA and CO₂; NADH is also produced.

Q7: Where does pyruvate oxidation take place?
A: In the mitochondrial matrix.

Q8: What is the function of the citric acid cycle (Krebs cycle)?
A: To extract high-energy electrons by oxidizing Acetyl-CoA.

Q9: Where does the citric acid cycle occur?
A: In the mitochondrial matrix.

Q10: What are the outputs of the citric acid cycle (per glucose)?
A: 4 CO₂, 2 ATP, 6 NADH, and 2 FADH₂.

Q11: What is oxidative phosphorylation?
A: The production of ATP using energy from electrons transferred through the ETC.

Q12: Where does oxidative phosphorylation occur?
A: In the inner membrane of the mitochondria (cristae).

Q13: What two processes make up oxidative phosphorylation?
A: The electron transport chain (ETC) and chemiosmosis.

Q14: What is the electron transport chain (ETC)?
A: A series of protein complexes that transfer electrons and pump protons to create a gradient.

Q15: What is chemiosmosis?
A: The use of a proton gradient to drive ATP synthesis via ATP synthase.

Q16: What is the final electron acceptor in the ETC?
A: Oxygen, which forms water after accepting electrons.

Q17: How many total ATP are produced from one glucose molecule (aerobically)?
A: Approximately 30–32 ATP.

Q18: What is NADH and FADH₂'s role in respiration?
A: They carry high-energy electrons to the electron transport chain.

Q19: What happens if oxygen is not available?
A: The cell performs anaerobic respiration or fermentation.

Q20: Why is cellular respiration essential for life?
A: It provides ATP, which powers nearly all cellular processes.