Question 1

Which of the following best describes the role of antioxidants in the body?

Accepted Answer

They donate electrons to free radicals, stabilizing them and preventing cellular damage.

Question 2

A patient presents with symptoms of fatigue, loss of appetite, blurred vision, and bone pain after taking high-dose vitamin A supplements. Which of the following best explains these symptoms?

Accepted Answer

Vitamin A toxicity due to excessive supplement intake

Question 3

Which of the following nutrients is a water-soluble antioxidant that enhances iron absorption and is required in higher amounts for smokers?

Accepted Answer

Vitamin C

Question 4

Which enzyme system requires selenium as a cofactor and is responsible for removing hydrogen peroxide from the body?

Accepted Answer

Glutathione peroxidase

Question 5

A diet high in which of the following foods would best help prevent vitamin E deficiency?

Accepted Answer

Vegetable oils, nuts, and seeds

Question 6

Which of the following statements about free radicals is correct?

Accepted Answer

Free radicals are unstable atoms with an unpaired electron that can damage cell membranes.

Question 7

A patient with a history of fat malabsorption is at increased risk for which of the following vitamin deficiencies, leading to erythrocyte hemolysis?

Accepted Answer

Vitamin E

Question 8

Which of the following is NOT a function of vitamin C?

Accepted Answer

Acts as a fat-soluble antioxidant in cell membranes

Question 9

A 45-year-old male with a diet low in fruits and vegetables, who smokes, is at increased risk for which vitamin deficiency disease characterized by bleeding gums and poor wound healing?

Accepted Answer

Scurvy (vitamin C deficiency)

Question 10

Which of the following best explains why antioxidants are thought to reduce the risk of cardiovascular disease (CVD)?

Accepted Answer

They scavenge free radicals, reduce inflammation, and decrease blood clot formation.

Question 11

Which of the following is a correct statement about beta-carotene?

Accepted Answer

It is a provitamin that can be converted to vitamin A in the body.

Question 12

A patient presents with brittle hair and nails, skin rashes, and muscle pain after taking high-dose mineral supplements. Which mineral toxicity is most likely responsible?

Accepted Answer

Selenium

Question 13

Which of the following equations best represents an oxidation-reduction (redox) reaction?

Accepted Answer

$$\mathrm{A} + \mathrm{B} \rightarrow \mathrm{A}^+ + \mathrm{B}^-$$

Question 14

Which of the following is a primary function of vitamin A in the body?

Accepted Answer

Cell differentiation and vision

Question 15

A child in a developing country presents with night blindness and xerophthalmia. Which nutrient deficiency is most likely responsible?

Accepted Answer

Vitamin A

Question 16

Which of the following best describes the process by which free radicals damage cell membranes?

Accepted Answer

They steal electrons from phospholipids, causing loss of membrane integrity.

Question 17

Which of the following is a marker for low-grade inflammation and is associated with increased risk for heart attack even when cholesterol levels are normal?

Accepted Answer

C-reactive protein (CRP)

Question 18

A patient with Keshan disease, characterized by impaired immunity and heart problems, is most likely deficient in which nutrient?

Accepted Answer

Selenium

Question 19

Which of the following best explains why heating oils can reduce their vitamin E content?

Accepted Answer

Vitamin E is destroyed by heat, oxygen, and ultraviolet light.

Question 20

Which of the following minerals is a component of the antioxidant enzyme superoxide dismutase?

Accepted Answer

Zinc

Antioxidant Nutrients and Their Role in Cellular Protection and Vision

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