What is a causative factor of Hirschsprung disease?
- A. Frequent evacuation of solids, liquids, and gases
- B. Excessive peristaltic movement
- C. Absence of parasympathetic ganglion cells in a portion of the colon
- D. One portion of the bowel telescoping into another
Correct Answer: C
Rationale: The correct answer is C: Absence of parasympathetic ganglion cells in a portion of the colon. Hirschsprung disease is a congenital condition characterized by the absence of nerve cells (ganglia) in parts of the colon. This absence leads to a lack of peristalsis in the affected segment, resulting in severe constipation and bowel obstruction. Choices A, B, and D are incorrect. Choice A describes symptoms of diarrhea rather than a causative factor of Hirschsprung disease. Excessive peristaltic movement (choice B) is not a causative factor but rather the opposite, as Hirschsprung disease is associated with reduced peristalsis. Choice D, which refers to intussusception, is a different condition unrelated to Hirschsprung disease.
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What is the term for the amount of heat required to raise the temperature of one kilogram of water by one degree Celsius?
- A. Calorie
- B. Joule
- C. Kilojoule
- D. Kilocalorie
Correct Answer: D
Rationale: The correct answer is D, Kilocalorie. The term kilocalorie, often referred to as a calorie, is the amount of heat required to raise the temperature of one kilogram of water by one degree Celsius. While Choice A, Calorie, is technically correct, it is not the most specific term for the described amount of heat. Choice B, Joule, is a unit of energy but not specifically related to the amount of heat required to raise the temperature of water. Choice C, Kilojoule, is also a unit of energy but not the precise term for the heat required to raise the temperature of water by one degree Celsius.
If a group of people consumes an amount of protein equal to the estimated average requirement for their population group, what percentage of people will receive insufficient amounts?
- A. 10
- B. 25
- C. 33
- D. 50
Correct Answer: D
Rationale: If a group consumes an amount of protein equal to the estimated average requirement, 50% of the people will receive insufficient amounts. The estimated average requirement is the amount of a nutrient that is estimated to meet the requirement of half the healthy individuals in a particular life stage and gender group. Therefore, 50% of the group will not be meeting their individual needs if they are consuming only the average requirement. Choices A, B, and C are incorrect because at the estimated average requirement level, a higher percentage than those values will receive insufficient amounts.
What is one characteristic that differentiates vitamins from minerals?
- A. Vitamins are organic compounds.
- B. Vitamins provide energy.
- C. Vitamins are considered micronutrients.
- D. Vitamins are essential in small amounts.
Correct Answer: A
Rationale: The correct answer is A. Vitamins are organic compounds, containing carbon, which is a key characteristic that differentiates them from minerals. Choice B is incorrect because vitamins do not provide energy; they are not a source of calories. Choice C is incorrect as both vitamins and minerals are considered micronutrients due to being essential in small amounts. Choice D is incorrect because while it is true that vitamins are needed in small amounts, this is not the characteristic that sets them apart from minerals.
You have been asked to help a top nutrition researcher conduct human experiments on vitamin C. As the subjects walk into the laboratory, you distribute all the vitamin C pill bottles to the girls and all the placebo pill bottles to the boys. What should you have done?
- A. Giving all the boys the vitamin C and the girls the placebo, and telling them what they were getting.
- B. Distributing the bottles randomly, randomizing the subjects, and telling them what they were getting.
- C. Telling the subjects which group they were in, but preventing yourself from knowing the contents of the pill bottles.
- D. Preventing yourself from knowing what is in the pill bottles, and distributing the bottles randomly to the subjects.
Correct Answer: D
Rationale: The correct approach in a scientific experiment is to prevent yourself from knowing the contents of the pill bottles and distribute them randomly to the subjects. This randomization helps to avoid bias and ensures that the results are not influenced by preconceived notions. Option A is incorrect because it introduces gender bias by assigning pills based on gender. Option B is incorrect as it mentions telling the subjects what they are getting, which could lead to placebo effects. Option C is incorrect as it suggests disclosing group information to the subjects, which can also introduce bias.
What dietary recommendation is essential for a child with phenylketonuria (PKU)?
- A. High-protein diet
- B. Low-fat diet
- C. Low-phenylalanine diet
- D. High-fiber diet
Correct Answer: C
Rationale: The correct answer is C: 'Low-phenylalanine diet.' Children with phenylketonuria (PKU) need to follow a low-phenylalanine diet to manage the condition. Phenylalanine is an amino acid found in protein-containing foods, and individuals with PKU have difficulty metabolizing it, leading to neurological damage and other complications. Therefore, restricting phenylalanine intake is crucial. Choice A, 'High-protein diet,' is incorrect because high protein intake would increase phenylalanine levels, worsening the condition. Choice B, 'Low-fat diet,' and Choice D, 'High-fiber diet,' are not the primary focus for PKU patients. The key dietary intervention for PKU is controlling phenylalanine intake, which is best achieved through a low-phenylalanine diet.