Answers with Rationales | Graded A+
Human Nutrition | Key Concepts: Macronutrients, Micronutrients, Digestion & Absorption,
Energy Balance, Metabolism, and Dietary Guidelines | Expert-Developed Q&A | 100%
University-Level & Exam-Ready
Introduction
This 2025/2026 NUTR 280 Exam 2 study resource includes 50 fully verified,
exam-style questions — the exact number required for the official NUTR 280 Exam
2 — developed in strict alignment with university-level nutrition science curricula. Each
question includes a correct answer in bold green, followed by a concise, evidence-based
rationale that explains biochemical pathways, physiological functions, and clinical/dietary
applications. This is a complete, exam-ready pack for 100% success.
Answer Format
All correct answers are highlighted in bold and green, with concise, evidence-based
rationales explaining biochemical processes, physiological mechanisms, and dietary
implications for optimal learning and retention.
Questions 1–50 (Full Exam Set – NUTR 280 Exam 2)
1. Which of the following is the primary source of energy for the brain
under normal conditions?
a) Fatty acids
b) Amino acids
c) Glucose
d) Lactate
c) Glucose
Rationale: The brain relies almost exclusively on glucose (~120 g/day). During prolonged
fasting, ketone bodies contribute, but glucose remains essential.
2. The Recommended Dietary Allowance (RDA) for protein in adults is:
a) 0.4 g/kg body weight
b) 0.8 g/kg body weight
c) 1.2 g/kg body weight
d) 1.6 g/kg body weight
b) 0.8 g/kg body weight
Rationale: The DRI sets the RDA at 0.8 g/kg for healthy adults to meet nitrogen balance and
essential amino acid needs.
, 3. Which enzyme initiates starch digestion in the mouth?
a) Pepsin
b) Lipase
c) Amylase
d) Trypsin
c) Amylase
Rationale: Salivary amylase (ptyalin) begins hydrolysis of α-1,4 glycosidic bonds in starch,
producing maltose and dextrins.
4. The majority of dietary fat absorption occurs in the:
a) Stomach
b) Duodenum
c) Jejunum
d) Ileum
c) Jejunum
Rationale: The jejunum has extensive surface area (villi/microvilli) and is the primary site for
triglyceride, cholesterol, and fat-soluble vitamin absorption.
5. A dietary carbohydrate classified as a non-digestible oligosaccharide is:
a) Sucrose
b) Lactose
c) Inulin
d) Maltose
c) Inulin
Rationale: Inulin is a fructan (prebiotic fiber) resistant to human digestive enzymes; fermented
by gut microbiota.
6. The hormone responsible for promoting glycogenolysis in the liver is:
a) Insulin
b) Glucagon
c) Cortisol
d) Ghrelin
b) Glucagon
Rationale: Glucagon activates glycogen phosphorylase, releasing glucose-1-phosphate →
glucose for blood.
7. The Acceptable Macronutrient Distribution Range (AMDR) for
carbohydrates is:
a) 10–35%
b) 20–35%
c) 45–65%
d) 70–80%
c) 45–65%
Rationale: The DRI AMDR for carbohydrates is 45–65% of total energy to ensure adequate
intake and minimize chronic disease risk.