Question

during oxidative phosphorylation, protons (h+) are pumped: into the matrix into the intermembrane space out of the mitochondria question 4 1 pts the molecule nadh is: an oxidized molecule a reduced molecule question 5 1 pts what is the chemical cycle that oxidizes pyruvate into carbon dioxide and occurs in the mitochondria? citric acid cycle fermentation glycolysis oxidative phosphorylation

Explanation:

• Question 4: NADH is formed when \(NAD^+\) gains electrons and hydrogen ions (\(H^+\)), which is the process of reduction. So, NADH is a reduced molecule.
• Question 5: The citric acid cycle (also known as the Krebs cycle) takes place in the mitochondria and oxidizes pyruvate (after it is converted to acetyl - CoA) to carbon dioxide. Fermentation occurs in the cytoplasm (in anaerobic conditions) and does not fully oxidize pyruvate to \(CO_2\). Glycolysis occurs in the cytoplasm and converts glucose to pyruvate. Oxidative phosphorylation is the process of ATP synthesis using the proton gradient, not the cycle that oxidizes pyruvate to \(CO_2\).

Answer:

• Question 4: B. a reduced molecule
• Question 5: A. citric acid cycle