超星 - Chapter 5 Vitamins

单选题

Which of the following criteria qualifies a compound as a vitamin?

A. The compound is necessary for health, but the body is unable to synthesize enough of the compound to maintain health.
B. The compound prevents chronic disease and cancer.
C. The compound is best absorbed if taken in supplement form.
D. The body is unable to synthesize the compound.

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单选题

Water-soluble and fat-soluble vitamins differ in which way?

A. Water-soluble vitamins are best absorbed in the presence of dietary fat.
B. Fat-soluble vitamins have much less potential for toxicity.
C. Water-soluble are less likely to be toxic.
D. Water-soluble vitamins are stored, whereas fat-soluble vitamins are excreted readily.

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单选题

Which of the following is most likely to result in vitamin toxicity if consumed daily over a long period of time?

A. Vitamin A supplements
B-vitamin complex
C. Fortified breakfast cereals
D. Spinach, kale, and other greens

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单选题

Why is taking excess amounts of fat-soluble vitamins more likely to cause toxicity than taking excesses of water-soluble vitamins?

A. In general, excesses of fat-soluble vitamins cannot be excreted as easily as water-soluble vitamins.
B. In general, water-soluble vitamins are more likely to be stored in the body than fat-soluble vitamins.
C. The body has higher requirements for water-soluble vitamins.
D. The body has higher requirements for fat-soluble vitamins.

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单选题

Which of the following statements is true?

A. Retinol is found only in plant foods.
B. Certain carotenoids are precursors for preformed vitamin A.
C. Vitamin A is necessary for normal blood clotting.
D. In children, vitamin A deficiency is called rickets.

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单选题

Which of the following foods is a naturally good source of vitamin D?

A. Fatty fish and fish oils
B. Dark orange and yellow vegetables
C. Whole-grain breads and cereals
D. Red meat

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单选题

The body needs folate to produce a coenzyme that

A. metabolizes vitamin E.
B. transmits nervous impulses.
C. helps form DNA.
D. protects fatty acids from oxidation.

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