BS Bachelor of Science: Science of Nutrition 3 — Questions and Answers
Question 1: During prolonged fasting, the brain adapts to use which alternative fuel source produced by the liver?
- Lactate
- Glycerol
- Ketone bodies (Correct answer)
- Free fatty acids
Correct answer: Ketone bodies
After glucose stores are depleted, the liver produces ketone bodies (acetoacetate and beta-hydroxybutyrate) from fatty acid oxidation, which the brain can use as fuel.
Question 2: The Dietary Reference Intake (DRI) framework includes which value defined as the average daily intake sufficient to meet the needs of 50% of healthy individuals?
- Recommended Dietary Allowance (RDA)
- Estimated Average Requirement (EAR) (Correct answer)
- Adequate Intake (AI)
- Tolerable Upper Intake Level (UL)
Correct answer: Estimated Average Requirement (EAR)
The EAR is the intake level estimated to meet the requirement of 50% of healthy individuals in a particular life stage and sex group.
Question 3: Pellagra is a nutritional deficiency disease caused by inadequate intake of which vitamin?
- Thiamine (B1)
- Riboflavin (B2)
- Niacin (B3) (Correct answer)
- Pyridoxine (B6)
Correct answer: Niacin (B3)
Pellagra presents with the '4 Ds'—dermatitis, diarrhea, dementia, and death—and results from niacin (B3) and/or tryptophan deficiency.
Question 4: Which measure is used to assess the quality of dietary protein by comparing its essential amino acid content to a reference protein pattern?
- Biological Value (BV)
- Net Protein Utilization (NPU)
- Protein Digestibility-Corrected Amino Acid Score (PDCAAS) (Correct answer)
- Chemical Score
Correct answer: Protein Digestibility-Corrected Amino Acid Score (PDCAAS)
PDCAAS evaluates protein quality by comparing the amino acid profile of a food protein to human requirements and correcting for digestibility, and was the FAO/WHO standard until DIAAS replaced it.
Question 5: Vitamin K2 (menaquinone) plays an essential role in which physiological process beyond blood coagulation?
- Collagen synthesis
- Calcium deposition in bone via carboxylation of osteocalcin (Correct answer)
- Iron absorption
- Antioxidant defense
Correct answer: Calcium deposition in bone via carboxylation of osteocalcin
Vitamin K2 activates osteocalcin through gamma-carboxylation, enabling it to bind calcium and incorporate it into bone mineral matrix.
Question 6: The respiratory quotient (RQ) of 0.70 indicates the body is predominantly oxidizing which macronutrient?
- Carbohydrate
- Protein
- Fat (Correct answer)
- Alcohol
Correct answer: Fat
Fat oxidation produces an RQ of approximately 0.70 because fat molecules have a high carbon-to-oxygen ratio, consuming more oxygen relative to COâ‚‚ produced.
Question 7: Which intestinal cell type is responsible for absorbing dietary lipids and packaging them into chylomicrons?
- Goblet cells
- Enterocytes (Correct answer)
- Paneth cells
- Enteroendocrine cells
Correct answer: Enterocytes
Enterocytes in the small intestinal mucosa absorb monoglycerides and fatty acids, reassemble triglycerides in the smooth ER, and package them into chylomicrons for lymphatic transport.
BS Bachelor of Science: Science of Nutrition 3
During prolonged fasting, the brain adapts to use which alternative fuel source produced by the liver?