Nutrition and Energy Metabolism (BMR, Starvation, Obesity, Metabolic Integration) MCQs

Biochemistry · 15 free questions with answers & explanations.

1. During prolonged starvation (>7 days), the brain significantly shifts its fuel utilization. Which metabolic adaptation allows the brain to reduce its dependence on glucose?
2. AMP-activated protein kinase (AMPK) acts as an energy sensor. When activated by a high AMP:ATP ratio, which combination of metabolic effects does it produce?
3. In kwashiorkor, hypoalbuminaemia is the central biochemical defect causing oedema. What is the primary mechanism by which isolated protein deficiency leads to hypoalbuminaemia despite adequate caloric intake?
4. During prolonged starvation (>72 hours), the brain shifts its primary fuel source. What biochemical event triggers and sustains this shift?
5. Leptin is a 16-kDa adipokine that regulates energy homeostasis. In diet-induced obesity in humans, serum leptin levels are typically:
6. A patient undergoing resting metabolic rate (RMR) measurement by indirect calorimetry has VO2 = 250 mL/min and VCO2 = 200 mL/min. What is the respiratory quotient (RQ) and what does it indicate about the primary fuel being oxidized?
7. During prolonged starvation (>5 days), the brain reduces its dependence on glucose and uses an alternative fuel. Which metabolic adaptation enables this shift?
8. Leptin, the satiety hormone produced by adipocytes, acts on which hypothalamic neurons to suppress appetite, and what is its primary intracellular signaling mechanism?
9. A patient maintained on total parenteral nutrition (TPN) develops peripheral neuropathy, confusion, and lactic acidosis after 3 weeks. Deficiency of which micronutrient explains all three features?
10. During the fed state, insulin promotes fatty acid synthesis in the liver. Which key regulatory enzyme is activated by insulin-mediated dephosphorylation to initiate this pathway?
11. During prolonged starvation (>72 hours), the brain adapts to use ketone bodies. The transporter that allows acetoacetate and beta-hydroxybutyrate to enter brain cells is:
12. AMP-activated protein kinase (AMPK) is called the 'energy sensor' of the cell. When activated by a high AMP:ATP ratio, which combination of metabolic effects is correct?
13. Leptin is produced by adipocytes and acts on the hypothalamus. In diet-induced obesity, a state of leptin resistance occurs. The PRIMARY intracellular mechanism of leptin resistance involves:
14. Respiratory quotient (RQ) of pure fat oxidation is 0.7. This is because:
15. Phenylketonuria (PKU) if untreated manifests with intellectual disability. The dietary management requires restriction of phenylalanine but supplementation of: