ACBN Practice Questions 2 — Questions and Answers
Question 1: Which fatty acid is considered the primary omega-3 precursor that the body uses to synthesize EPA and DHA?
- Linoleic acid (LA)
- Alpha-linolenic acid (ALA) (Correct answer)
- Arachidonic acid (AA)
- Gamma-linolenic acid (GLA)
Correct answer: Alpha-linolenic acid (ALA)
Alpha-linolenic acid (ALA) is the essential omega-3 fatty acid that serves as the precursor for EPA and DHA synthesis in the body.
Question 2: A patient presents with night blindness and dry, rough skin. Which vitamin deficiency is most likely responsible?
- Vitamin D
- Vitamin K
- Vitamin A (Correct answer)
- Vitamin E
Correct answer: Vitamin A
Vitamin A deficiency causes night blindness and xerosis (dry skin) because retinol is essential for rhodopsin synthesis and epithelial cell integrity.
Question 3: The Dietary Reference Intake term that represents the average daily intake sufficient to meet the needs of 50% of healthy individuals is called the:
- 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 Estimated Average Requirement (EAR) is the intake that meets the needs of 50% of the healthy population, and it forms the basis for calculating the RDA.
Question 4: Which enzyme is responsible for the initial digestion of starch in the mouth?
- Pepsin
- Lipase
- Salivary amylase (Correct answer)
- Sucrase
Correct answer: Salivary amylase
Salivary amylase (ptyalin) begins carbohydrate digestion in the oral cavity by cleaving alpha-1,4-glycosidic bonds in starch.
Question 5: A client following a strict vegan diet is at greatest risk of deficiency in which nutrient?
- Vitamin C
- Vitamin B12 (Correct answer)
- Folate
- Magnesium
Correct answer: Vitamin B12
Vitamin B12 is found almost exclusively in animal products, making vegans highly susceptible to deficiency without supplementation.
Question 6: The thermic effect of food (TEF) accounts for approximately what percentage of total daily energy expenditure in most individuals?
- 1-3%
- 5-10% (Correct answer)
- 15-20%
- 25-30%
Correct answer: 5-10%
The thermic effect of food typically represents 5-10% of total energy expenditure, reflecting the metabolic cost of digesting, absorbing, and storing nutrients.
Question 7: Which mineral is a critical component of glutathione peroxidase, an antioxidant enzyme that protects cells from oxidative damage?
- Zinc
- Iron
- Selenium (Correct answer)
- Copper
Correct answer: Selenium
Selenium is an essential component of glutathione peroxidase, which catalyzes the reduction of hydrogen peroxide and lipid peroxides to protect cells from oxidative stress.
ACBN Practice Questions 2
Which fatty acid is considered the primary omega-3 precursor that the body uses to synthesize EPA and DHA?