What two major kinds of chemical reactions occur in the citric acid cycle, and how are these reactions indicated symbolically?

Correct Answer: B

Rationale: The citric acid cycle primarily involves oxidation reactions, where NAD⁺ and FAD are reduced to NADH and FADH₂ as electrons are transferred from substrates, and decarboxylation reactions, where CO₂ is removed (e.g., from isocitrate and α-ketoglutarate). These processes are symbolically indicated by NAD⁺/FAD (for oxidation) and CO₂ (for decarboxylation). Other options mismatch the reactions (e.g., synthesis, hydrolysis, phosphorylation, dehydration) or symbols (e.g., H₂O, O₂, ATP, P) with the cycle’s primary processes.

Correct Answer: A

Rationale: insulin as glucagon's antagonist ; cortisol , adrenaline , and thyroxine have other roles.

Correct Answer: C

Rationale: leptin as the key long-term regulator ; insulin and glucagon are short-term, ghrelin stimulates hunger.

Correct Answer: B

Rationale: Andrea's symptoms (flushing, chattering) as fever from a raised hypothalamic set point ; not cold , exercise , or dehydration .

Correct Answer: B

Rationale: Catabolism is the metabolic process that breaks down complex molecules into simpler ones, releasing energy.