The principal cation in plasma and interstitial fluid is:

Correct Answer: A

Rationale: The principal cation in plasma and interstitial fluid is sodium. Sodium plays a crucial role in maintaining fluid balance and is the primary cation in extracellular fluids like plasma and interstitial fluid. Potassium is the primary cation within cells, not in extracellular fluids, making it an incorrect choice. Calcium and magnesium are essential minerals but are not the principal cations in plasma and interstitial fluid, so they are also incorrect choices.

Correct Answer: C

Rationale: The correct answer is C because MyPlate actually provides more specific guidance compared to MyPyramid. MyPlate was designed to simplify the dietary recommendations for consumers by focusing on a visual representation of a plate divided into food groups, making it easier to understand and apply. Choices A, B, and D accurately describe features of MyPlate: replacing MyPyramid, providing personalized dietary guidance through an interactive website, and grouping foods with similar nutrients while emphasizing proportionality of food selections.

Correct Answer: C

Rationale: Vitamin A can be stored in the liver to meet basic needs for at least 1 year. This storage capacity allows the body to have a reserve of Vitamin A to sustain its needs over an extended period. Choices A, B, and D are incorrect because they underestimate the storage capacity of Vitamin A in the liver, which can last longer than these durations.

Correct Answer: C

Rationale: The correct answer is Vitamin D. Although vitamin D, also known as calciferol, has been called a vitamin, it is more appropriately classified as a hormone. Like hormones, vitamin D acts to control the function of other cell types. For example, it helps the body absorb and regulate skeletal calcium and phosphorus levels. Choice A (Vitamin A) plays a crucial role in vision and immune function. Choice B (Vitamin B) is a complex of different vitamins that play various roles in the body. Choice D (Vitamin C) is important for collagen production and acts as an antioxidant.

Correct Answer: D

Rationale: The correct answer is D, Perspiration. Water loss can occur through respiration inflammation, strenuous exercise, and diarrhea. Perspiration, also known as sweating, is a mechanism by which the body regulates temperature and eliminates some waste products, but it is not a cause of water loss. The body loses water through sweating, but this loss is mainly for cooling purposes, and it is not a primary mechanism for water loss like respiration, exercise, or diarrhea.

Correct Answer: D

Rationale: The correct answer is D. Phosphorus plays a crucial role in ATP energy release, the metabolism of fats, carbohydrates, and proteins, and regulation of acid-base balance. Choices A, B, and C are incorrect. Phosphorus is not directly involved in blood clotting, transmission of nerve impulses, muscle contraction, or calcium homeostasis. It also has known metabolic functions and is not associated with caries prevention.

Correct Answer: D

Rationale: The correct answer is D, Aspartame. Aspartame contains phenylalanine, which is contraindicated for individuals with phenylketonuria (PKU), a genetic disorder that impairs phenylalanine metabolism. Therefore, patients with PKU should avoid aspartame. Choices A, B, and C (Cyclamate, Acesulfame-K, Saccharin) are considered safe for individuals with PKU as they do not contain phenylalanine and can be recommended as alternatives to sugar for these patients.

Correct Answer: A

Rationale: The correct answer is A, Type 1 Diabetes. The prevalence of Type 1 Diabetes is seen in approximately 5% to 10% of cases. This statement highlights a key epidemiological characteristic of Type 1 Diabetes. Choice B, Type 2 Diabetes, is incorrect because the prevalence mentioned does not align with Type 2 Diabetes, which has a much higher prevalence in the general population. Choices C and D are not relevant to the question and can be disregarded.

Correct Answer: D

Rationale: Iron, fiber, and B vitamins are most likely to become insufficient when carbohydrates are eliminated from the diet to lose weight. Carbohydrates are a primary source of B vitamins and fiber in the diet. Iron can also be obtained from plant-based sources like legumes and whole grains, which are often eliminated when carbohydrates are restricted. Choices A, B, and C are incorrect because protein, vitamin K, vitamin A, and vitamin C are not primarily sourced from carbohydrates and are less likely to become insufficient solely due to carbohydrate elimination.