Section A — Coach Food — Metabolic Biochemistry and Clinical Nutrition
This section covers the Bachelor's chapter on Metabolic Biochemistry and Clinical Nutrition, Lessons 1 through 5: Macronutrient Metabolism at Molecular Depth, Energy Regulation and Homeostasis, Micronutrient Biochemistry, Clinical Nutrition and Disease Pathophysiology, and Nutritional Research Methods. All material is already in the chapter — no new content.
Part A — Vocabulary (20 points, 2 points each)
Select the single best answer for each question.
1. mTORC1 is best defined as:
A) A mitochondrial protein involved in oxidative phosphorylation B) Mechanistic Target of Rapamycin Complex 1 — a serine/threonine kinase complex integrating growth factor, amino acid, and energy signals to drive protein synthesis, lipid synthesis, and autophagy regulation C) A transcription factor in nuclear hormone receptor signaling D) An enzyme in glycolysis
2. Sestrin2 is:
A) The active hormonal form of vitamin D B) A cytosolic leucine sensor that inhibits GATOR2 in the absence of leucine, releasing the inhibition when leucine binds C) A glucose transporter D) A mitochondrial uncoupling protein
3. The urea cycle (Krebs-Henseleit 1932) is:
A) The cellular machinery for protein synthesis B) The five-enzyme hepatic pathway that converts ammonia from amino acid catabolism into urea for renal excretion, partitioned between mitochondrion and cytosol C) A pathway for glucose metabolism D) An obsolete metabolic concept
4. The carnitine shuttle is best described as:
A) A system for amino acid transport across the blood-brain barrier B) The CPT-I / carnitine acylcarnitine translocase / CPT-II machinery that moves long-chain fatty acyl groups across the inner mitochondrial membrane for β-oxidation C) A pathway for cholesterol synthesis D) A glucose transporter system
5. HMG-CoA reductase is:
A) The rate-limiting enzyme of cholesterol biosynthesis (HMG-CoA to mevalonate); the target of the statin drug class B) An enzyme in glycolysis C) A vitamin D receptor D) A protein in oxidative phosphorylation
6. Leptin (Zhang and Friedman 1994) is best characterized as:
A) A neurotransmitter B) A 167-amino-acid hormone secreted principally by adipocytes that signals long-term energy storage to the hypothalamus, with deficiency causing extreme obesity in the ob/ob mouse model C) An anti-inflammatory cytokine D) A bone-forming hormone
7. UCP1 (Uncoupling Protein 1) is:
A) A muscle contractile protein B) An inner-mitochondrial-membrane protein in brown adipocytes that dissipates the proton gradient as heat rather than as ATP synthesis C) A glucose transporter D) A regulator of insulin secretion
8. Familial Hypercholesterolemia (FH) is:
A) An acquired condition caused by diet B) An inherited disorder caused by LDL receptor mutations (Brown and Goldstein work) producing severely reduced LDL clearance, very high LDL-C levels, and aggressive early-onset cardiovascular disease in homozygotes C) A type 2 diabetes variant D) Not associated with cardiovascular risk
9. PROT-AGE (Bauer et al. 2013) refers to:
A) An age-related decline in protein synthesis B) Evidence-informed protein recommendations for older adults specifying ~1.0-1.2 g/kg/day for healthy older adults and higher (1.2-1.5+ g/kg/day) for those with acute or chronic illness — above the 0.8 g/kg/day RDA derived from young-adult nitrogen balance studies C) An obsolete dietary guideline D) A specific brand of protein supplement
10. Doubly Labeled Water (DLW) is:
A) A type of structured water B) An isotopic technique using ²H and ¹⁸O to measure total energy expenditure under free-living conditions; gold standard for free-living TEE, established by Schoeller and colleagues C) A supplement claim D) Alkaline water
Part B — Concept Comprehension (20 points, 2 points each)
Select the single best answer for each question.
11. The Krebs and Johnson 1937 Enzymologia paper established:
A) The discovery of insulin B) The citric acid cycle as the central oxidative pathway through which carbohydrate, fat, and protein catabolism converge — the metabolic crossroads of all three macronutrient classes C) The discovery of cholesterol D) The role of vitamin D in bone health
12. The mTORC1 cascade from leucine availability to S6K1 phosphorylation involves:
A) Leucine directly binding mTOR B) Leucine → Sestrin2 binding → release of Sestrin2 from GATOR2 → GATOR2 inhibits GATOR1 → Rag GTPases form active heterodimer → recruit mTORC1 to lysosomal surface → Rheb-GTP activates mTORC1 kinase → S6K1/4E-BP1 phosphorylation C) Leucine activating PI3K directly D) Leucine signaling through nuclear hormone receptors
13. Leptin signaling through the leptin receptor (LepRb) operates principally through:
A) Direct ion channel gating B) JAK2/STAT3 cascade — LepRb dimerization activates receptor-associated JAK2 → phosphorylates STAT3 → STAT3 nuclear translocation → transcriptional regulation, with parallel SHP2/MAPK, PI3K/Akt, and AMPK pathway effects C) cAMP elevation only D) G-protein-coupled receptor signaling exclusively
14. The arcuate POMC/AgRP/MC4R circuit is:
A) A reflex pathway for movement B) The principal central energy balance circuit — POMC neurons (anorexigenic) release α-MSH to activate MC4R signaling, AgRP neurons (orexigenic) antagonize MC4R; leptin activates POMC and inhibits AgRP; ghrelin produces the opposite pattern C) A circuit only active during sleep D) Unrelated to energy regulation
15. Adaptive thermogenesis refers to:
A) An abstract concept without molecular substrate B) The active adjustment of energy expenditure (reduction in deficit, increase in surplus) beyond what mass change alone predicts, with brown adipose tissue UCP1-driven non-shivering thermogenesis as one principal substrate C) Fever during illness D) Exercise-induced heat production
16. The vitamin D receptor (VDR) operates as:
A) A G-protein-coupled receptor B) A nuclear hormone receptor that, ligand-bound by 1,25-(OH)₂D, heterodimerizes with RXR and binds VDREs to regulate transcription of calcium-, phosphate-, and immune-related genes C) An ion channel D) A receptor tyrosine kinase
17. The Shulman laboratory ectopic lipid framework of insulin resistance proposes:
A) Insulin resistance is purely genetic B) Intramyocellular lipid (IMCL) in muscle and intrahepatic lipid in liver drive insulin resistance through diacylglycerol (DAG) accumulation → PKCε/θ activation → serine phosphorylation of IRS-1/2 → reduced insulin signaling C) Insulin resistance is caused by viral infection D) Insulin resistance is caused by inadequate protein intake
18. The DASH dietary pattern (Appel et al. 1997 NEJM) demonstrated:
A) No effect on blood pressure B) Systolic BP reductions of approximately 5-11 mmHg in hypertensive patients on the DASH dietary pattern alone (no caloric restriction, no medication change), with effect size approaching pharmacological monotherapy C) Effects only with caloric restriction D) Effects only in specific ethnic groups
19. The Ioannidis critique of nutritional epidemiology addresses:
A) The strength of nutrition research B) The methodological constraints of nutritional epidemiology — small effect sizes claimed on the basis of large but noisy datasets, dependent variables sometimes selected post-hoc, contradicting findings across studies — supporting reform including pre-registration, larger samples, transparent reporting C) Specific dietary recommendations D) Vitamin D supplementation only
20. The Bachelor's chapter's framework for evaluating popular nutrition claims is:
A) Accept claims that align with widely-held beliefs B) The five-point framework: mechanism plausibility, study design adequacy, effect size in context, replication across populations, translation appropriateness — applied as portable evaluation infrastructure across nutrition claims and broader curriculum C) Reject all popular claims D) Trust major media sources without scrutiny
Part C — Application (30 points, 6 points each)
Write 4-6 complete sentences with specific molecular and mechanistic detail for each question.
21. mTORC1 cascade integration. Walk the mTORC1 cascade in skeletal muscle from leucine entry to protein synthesis activation, naming each upstream sensor at the molecular level. Then articulate how the same pathway is engaged from the mechanical-load arm in Move Bachelor's Lesson 1 (the contraction-signaling angle through PI3K/Akt/TSC1-TSC2/Rheb-GTP). Why does the chapter emphasize that the two arms converge at mTORC1 as an AND gate?
22. Disease pathophysiology integration. Apply the Shulman ectopic lipid framework to explain metabolic syndrome pathogenesis. Walk from sustained positive energy balance through intramyocellular and intrahepatic lipid accumulation through DAG-PKCε/θ-IRS-1 serine phosphorylation to systemic insulin resistance, dyslipidemia, and hypertension. Why does the framework support that metabolic syndrome is not "lack of willpower" but specific cellular pathophysiology?
23. Lipid hypothesis honestly. The Bachelor's chapter walks the lipid hypothesis at the level of the actual studies. Articulate what is settled (LDL is causally related to ASCVD; pattern-level evidence is robust), what is contested (the saturated-fat-specific guidance), and what does the pattern-level evidence (Appel 1997 DASH, Estruch PREDIMED) support for cardiovascular nutrition recommendations.
24. Safety recognition (eating disorder vigilance). A college roommate in a pre-health program has been calculating macros with increasing precision, weighing themselves multiple times daily, expressing anxiety around social meals, and exercising compulsively to "earn" food. Walk through the recognition signs from the chapter, identify the appropriate resources to mention (with currently active phone numbers), and identify the older NEDA helpline that you should not cite. Apply the descriptive-not-prescriptive framing the chapter maintains.
25. Methodological consciousness. The VITAL trial (Manson et al. 2019 NEJM) randomized 25,871 general-population adults to vitamin D 2000 IU/day vs placebo with cardiovascular and cancer endpoints. Walk what the trial demonstrated (the null findings for principal endpoints) and what it did not demonstrate (effects in deficient populations, other endpoints, longer follow-up). Why does the discrepancy between observational vitamin D research and randomized trial findings serve as a cautionary case in nutritional epidemiology, parallel to vitamin E and beta-carotene divergences?
Continue to Section B — Coach Brain.