ATP & Energy Flow
Redox & Electron Transport
Stages of Respiration
Fermentation & Anaerobic Respiration
100
What is the immediate source of energy for most cellular work?
ATP (adenosine triphosphate). Cells hydrolyze ATP into ADP + Pi, releasing energy. (Lecture Slide 25: ATP powers cellular
100
What does "LEO the lion says GER" mean?
Oxidation is Loss (OIL) of electrons, Reduction is Gain (RIG) of electrons. (Slide 9: Redox reactions.)
100
What is the net ATP gain from glycolysis?
: 2 ATP (4 ATP produced - 2 ATP used). (Slide 31: Glycolysis energy yield.)
100
What does yeast produce in ethanol fermentation?
Ethanol, CO₂, and NAD⁺. (Slide 66: Fermentation pathways.) 
200
Explain why ATP is unstable and why this is beneficial.
ATP has three negatively charged phosphate groups, creating repulsion. This instability makes ATP highly reactive, allowing cells to use energy efficiently. (Slide 27: ATP hydrolysis drives endergonic reactions.)
200
Why does FADH₂ produce less ATP than NADH?
FADH₂ bypasses Complex I and enters at Complex II, resulting in fewer protons being pumped, yielding only 2 ATP instead of 3 ATP like NADH. (Slide 58: Energy yield of NADH vs. FADH₂.)
200
Which step produces the most ATP?
Oxidative phosphorylation (Electron Transport Chain) generates ~26-28 ATP per glucose. (Slide 52: ATP yield per step.) 
200
Why does lactic acid fermentation regenerate NAD⁺?
It allows glycolysis to continue in the absence of oxygen. (Slide 66: Purpose of fermentation.)
300
Predict what happens if ATP synthase is inhibited.
No ATP is produced via oxidative phosphorylation, leading to cell death since ATP is essential for metabolism 
300
If a drug prevents oxygen from accepting electrons, what happens?
The electron transport chain stops, leading to no ATP production and cell death. (Slide 63: Oxygen as the final electron acceptor.)
300
If a patient has a defect in pyruvate oxidation, what accumulates?
Pyruvate builds up and is converted into lactate or ethanol instead of Acetyl-CoA. (Slide 41: Pyruvate oxidation.)
300
Why do muscle cells use fermentation during exercise?
Oxygen is limited, so cells switch to fermentation for rapid ATP production, despite low yield. (Slide 38: Anaerobic vs. aerobic respiration.) 
400
How does substrate-level phosphorylation differ from oxidative phosphorylation?
Substrate-level phosphorylation directly transfers a phosphate to ADP (in glycolysis & Krebs cycle), while oxidative phosphorylation uses the electron transport chain and proton gradient to generate ATP. (Slide 25: ATP formation pathways.) 
400
Predict how ATP production changes in cyanide poisoning.
Cyanide blocks Complex IV, preventing oxygen from being the final electron acceptor, halting ATP production. (Slide 53: ETC function.) 
400
How does a high-fat diet impact the Krebs cycle?
Fatty acids enter as Acetyl-CoA, increasing Krebs cycle activity but also raising NADH/FADH₂, which may slow glycolysis. (Slide 72: Fat metabolism.)
400
How do some bacteria survive without mitochondria?
They use anaerobic respiration or fermentation for ATP. (Slide 64: Prokaryotic energy metabolism.)
500
Explain why only 34% of glucose’s energy is converted to ATP. Where does the rest go?
The rest is lost as heat, which helps maintain body temperature. (Slide 59: Energy yield of respiration.)
500
How does the proton gradient drive ATP synthesis?
Protons flow back into the mitochondrial matrix via ATP synthase, driving ATP production. (Slide 56: Chemiosmosis & ATP synthase.)
500
Why is glycolysis considered ancient in evolution?
Glycolysis occurs in the cytoplasm and does not require oxygen, suggesting it evolved in early anaerobic conditions. (Slide 69: Evolutionary significance of glycolysis.)
500
Which food products rely on fermentation, and how does this process work?
Yogurt, cheese, and bread use bacterial/yeast fermentation to produce lactic acid or CO₂, altering texture and taste. (Slide 66: Fermentation in food production.) 