RD Exam Human Nutrition & Physiology Practice Questions
Human Nutrition & Physiology makes up 6 of every 50 questions on a Tigertest RD Exam practice test. Here are 10 of the 24 questions on it, each with the answer and the reason.
Updated by the Tigertest team. Based on the CDR Registration Examination for Dietitians test specifications. Original questions; 50 per test, weighted like the real exam. Not affiliated with the Commission on Dietetic Registration.
1. A snack has 12 g protein, 8 g fat and 30 g carbohydrate. How many kilocalories does it provide?
- A.210 kcal
- B.240 kcal
- C.200 kcal
- D.224 kcal
Answer: B. Protein and carbohydrate give 4 kcal/g and fat 9 kcal/g: (12 x 4) + (8 x 9) + (30 x 4) = 48 + 72 + 120 = 240. Using 4 kcal/g for everything gives 200, and 7 kcal/g (the value for alcohol) for the fat gives 224.
2. Where is most dietary iron absorbed?
- A.Stomach
- B.Colon
- C.Terminal ileum
- D.Duodenum
Answer: D. Iron is absorbed mainly in the duodenum and upper jejunum, helped by stomach acid and vitamin C. The terminal ileum is where vitamin B12 and bile salts are absorbed.
3. Absorption of vitamin B12 depends on intrinsic factor made by which cells?
- A.Parietal cells of the stomach
- B.Goblet cells of the colon
- C.Chief cells of the stomach
- D.Beta cells of the pancreas
Answer: A. Parietal cells secrete hydrochloric acid and intrinsic factor, which binds B12 for uptake in the terminal ileum. Chief cells secrete pepsinogen.
4. A fatty meal reaches the duodenum. Which hormone triggers gallbladder contraction and pancreatic enzyme release?
- A.Secretin
- B.Ghrelin
- C.Cholecystokinin
- D.Gastrin
Answer: C. CCK is released by the duodenum in response to fat and protein. Secretin mainly triggers bicarbonate release, gastrin stimulates stomach acid, and ghrelin signals hunger.
5. A man who drinks heavily presents with confusion, an unsteady gait and abnormal eye movements. Which deficiency is most likely?
- A.Riboflavin
- B.Vitamin B6
- C.Thiamin
- D.Niacin
Answer: C. Wernicke encephalopathy comes from thiamin (B1) deficiency and is common with chronic alcohol use. Thiamin is given before glucose because glucose metabolism uses up the remaining supply.
6. A patient has dermatitis in sun-exposed areas, diarrhea and confusion. Which nutrient deficiency fits?
- A.Niacin
- B.Vitamin C
- C.Folate
- D.Thiamin
Answer: A. Pellagra is niacin deficiency, with the three Ds: dermatitis, diarrhea and dementia (a fourth, death, if untreated). The body can also make niacin from tryptophan.
7. A patient on a restrictive diet has bleeding gums, corkscrew hairs and bruises around hair follicles. Which deficiency fits?
- A.Zinc
- B.Vitamin K
- C.Vitamin A
- D.Vitamin C
Answer: D. Scurvy shows perifollicular bleeding, corkscrew hairs, swollen bleeding gums and poor wound healing because vitamin C is needed for collagen. Vitamin K deficiency causes bleeding without the hair changes.
8. A patient has megaloblastic anemia with numbness in the feet. Which deficiency should be suspected first?
- A.Vitamin B6
- B.Vitamin B12
- C.Folate
- D.Iron
Answer: B. B12 and folate deficiency both cause megaloblastic anemia, but only B12 deficiency causes nerve damage. Giving folate alone can correct the anemia while nerve damage continues.
9. Which vitamin is converted in the kidney to its most active form?
- A.Vitamin K
- B.Vitamin D
- C.Vitamin A
- D.Vitamin E
Answer: B. Vitamin D is hydroxylated in the liver to 25-hydroxyvitamin D and then in the kidney to 1,25-dihydroxyvitamin D (calcitriol). That is why chronic kidney disease leads to low active vitamin D.
10. In phenylketonuria, which amino acid becomes conditionally essential because it can no longer be made from phenylalanine?
- A.Glutamine
- B.Arginine
- C.Leucine
- D.Tyrosine
Answer: D. Phenylalanine hydroxylase normally converts phenylalanine to tyrosine. When the enzyme is missing, tyrosine must come from the diet or the medical formula.
Practice all 24 human nutrition & physiology questions, and the rest of the 200-question bank, in the free RD Exam training sets. Questions you miss come back until you have mastered them.
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