Nokea
Scurvy is caused by a deficiency of which vitamin?
- A. Vitamin A
- B. Vitamin D
- C. Vitamin E
- D. Vitamin K
Correct Answer: C
Rationale: Scurvy is caused by a deficiency of vitamin C, not vitamin E. The symptoms of scurvy include spontaneous gingival hemorrhaging, perifollicular petechiae, follicular hyperkeratosis, diarrhea, fatigue, depression, and cessation of bone growth. Vitamin A (Choice A) is important for vision and immune function, Vitamin D (Choice B) is essential for bone health, and Vitamin K (Choice D) is necessary for blood clotting. However, none of these vitamins are associated with scurvy.
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Which vitamin acts most like a hormone?
- A. Vitamin A
- B. Vitamin B
- C. Vitamin D
- D. Vitamin C
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.
Each statement is true of calcium within saliva, except one. Which is the exception?
- A. Saliva is supersaturated with calcium.
- B. Saliva is a source of calcium to mineralize an immature or demineralized enamel surface.
- C. Calcium and phosphate in saliva provide a buffering action.
- D. Calcium within saliva increases dental caries.
Correct Answer: D
Rationale: The correct answer is D. Calcium within saliva does not increase dental caries; in fact, the buffering action provided by calcium and phosphate in saliva inhibits caries formation by preventing the dissolution of enamel by plaque biofilm. Choice A is correct as saliva is indeed supersaturated with calcium. Choice B is correct as saliva serves as a source of calcium to mineralize an immature or demineralized enamel surface. Choice C is correct as calcium and phosphate in saliva do provide a buffering action to protect teeth from acids.
Which animal-derived food contains the most significant level of carbohydrates?
- A. Egg
- B. Beef
- C. Milk
- D. Poultry
Correct Answer: C
Rationale: Milk contains the most significant level of carbohydrates among animal-derived foods. Milk and milk products supply significant quantities of carbohydrate in the form of lactose. Eggs, beef, and poultry are not significant sources of carbohydrates compared to milk. In cheese making, lactose is removed as a by-product, reducing the carbohydrate content further.
Fat-soluble vitamins are different from water-soluble vitamins because the body is able to store only small amounts of fat-soluble vitamins.
- A. Both the statement and the reason are correct and related.
- B. Both the statement and the reason are correct but are not related.
- C. The statement is correct, but the reason is not correct.
- D. The statement is not correct, but the reason is correct.
Correct Answer: C
Rationale: The statement is correct, but the reason is not correct. A major difference between fat-soluble and water-soluble vitamins is that the body is able to store larger amounts of fat-soluble vitamins. Vitamins A and D are stored for long periods; therefore, minor shortages might not be identified until drastic depletion has occurred. Observable signs and symptoms of a dietary deficiency are often not identified until they are in an advanced state. Water-soluble vitamins, on the other hand, are not stored in the body and are excreted in the urine if taken in excess, making it harder to reach toxic levels.
Vitamin deficiencies, especially the B-complex vitamins, seldom occur in isolation. Folate, a B-complex vitamin, is the exception because it functions separately from other vitamins.
- A. Both statements are true.
- B. Both statements are false.
- C. The first statement is true; the second is false.
- D. The first statement is false; the second is true.
Correct Answer: C
Rationale: The first statement is true; the second is false. If a deficiency of one vitamin is suspected, symptoms of other vitamin B deficiencies also may be present. Folate deficiencies usually occur with other nutrient deficiencies. Specifically, folate functions in conjunction with vitamins B12 and C in maintaining normal levels of mature red blood cells.