MCQ on Antioxidants

🟢 Easy Level (1–10)

1. What are antioxidants?
   a) Harmful toxins
   b) Proteins that cause inflammation
   c) Compounds that prevent cell damage ✅
   d) Digestive enzymes
   Explanation: Antioxidants protect cells from damage caused by free radicals.
2. Which of the following is a powerful antioxidant vitamin?
   a) Vitamin B12
   b) Vitamin C ✅
   c) Vitamin K
   d) Vitamin D
   Explanation: Vitamin C neutralizes free radicals.
3. Vitamin E is known for its role as a:
   a) Blood thinner
   b) Antioxidant ✅
   c) Mineral transporter
   d) Carbohydrate enzyme
   Explanation: Vitamin E helps protect cell membranes from oxidation.
4. Which of the following foods is high in antioxidants?
   a) White bread
   b) Fried foods
   c) Berries ✅
   d) Soft drinks
   Explanation: Berries like blueberries and strawberries are antioxidant-rich.
5. Free radicals can cause damage to:
   a) DNA and cells ✅
   b) Muscles only
   c) Bones only
   d) Hair only
   Explanation: Free radicals can damage various cellular components, including DNA.
6. Which of the following is a naturally occurring antioxidant enzyme?
   a) Amylase
   b) Catalase ✅
   c) Lipase
   d) Pepsin
   Explanation: Catalase breaks down hydrogen peroxide, a harmful by-product of metabolism.
7. A diet high in antioxidants may help prevent:
   a) Scurvy only
   b) Chronic diseases ✅
   c) Only bacterial infections
   d) Weight gain
   Explanation: Antioxidants reduce oxidative stress that contributes to diseases.
8. Carotenoids act as:
   a) Proteins
   b) Antioxidants ✅
   c) Antibiotics
   d) Enzymes
   Explanation: Carotenoids are plant pigments with antioxidant properties.
9. Which vitamin is a fat-soluble antioxidant?
   a) Vitamin C
   b) Vitamin E ✅
   c) Vitamin B2
   d) Vitamin B12
   Explanation: Vitamin E is stored in fat tissues and acts as an antioxidant.
10. One major function of antioxidants is to:
    a) Build muscle
    b) Increase blood sugar
    c) Reduce oxidative stress ✅
    d) Aid digestion
    Explanation: Antioxidants neutralize oxidative damage from free radicals.

🟡 Moderate Level (11–20)

11. Flavonoids found in plants function primarily as:
    a) Digestive aids
    b) Antioxidants ✅
    c) Proteins
    d) Carbohydrates
    Explanation: Flavonoids are plant compounds with antioxidant effects.
12. Selenium is important in the diet because:
    a) It boosts cholesterol
    b) It acts as an antioxidant ✅
    c) It prevents bone loss
    d) It helps in fat storage
    Explanation: Selenium works with enzymes to reduce oxidative stress.
13. Which vitamin works closely with vitamin E to regenerate its antioxidant capacity?
    a) Vitamin A
    b) Vitamin D
    c) Vitamin C ✅
    d) Vitamin K
    Explanation: Vitamin C helps recycle oxidized vitamin E.
14. Which fruit is considered a good source of antioxidants?
    a) Banana
    b) Apple
    c) Pomegranate ✅
    d) Potato
    Explanation: Pomegranate contains high levels of polyphenols and flavonoids.
15. Antioxidants help to protect against which of the following?
    a) Sunburn only
    b) Oxidative damage ✅
    c) All bacterial infections
    d) Hair fall
    Explanation: Antioxidants combat oxidative damage from free radicals.
16. Beta-carotene is a precursor of:
    a) Vitamin C
    b) Vitamin E
    c) Vitamin A ✅
    d) Vitamin B12
    Explanation: Beta-carotene is converted into vitamin A in the body.
17. Resveratrol is an antioxidant commonly found in:
    a) Grapes ✅
    b) Milk
    c) Eggs
    d) Bread
    Explanation: Found in grape skins and red wine, resveratrol has antioxidant effects.
18. Oxidative stress results when:
    a) Antioxidants exceed free radicals
    b) Free radicals exceed antioxidants ✅
    c) Fatty acids are low
    d) Blood pressure rises
    Explanation: Oxidative stress occurs when free radicals overwhelm the body’s defense.
19. Which mineral works as a cofactor for antioxidant enzymes?
    a) Calcium
    b) Zinc ✅
    c) Phosphorus
    d) Chloride
    Explanation: Zinc supports enzymes like superoxide dismutase.
20. Polyphenols are found in:
    a) Processed meat
    b) Green tea ✅
    c) Soda
    d) Cheese
    Explanation: Polyphenols are abundant in tea, fruits, and vegetables.

🔴 Hard Level (21–30)

21. Which antioxidant enzyme catalyzes the breakdown of superoxide radicals?
    a) Amylase
    b) Superoxide dismutase ✅
    c) Lipase
    d) Trypsin
    Explanation: Superoxide dismutase (SOD) converts superoxide into less reactive molecules.
22. Which is NOT a function of antioxidants?
    a) Neutralize free radicals
    b) Prevent oxidative cell damage
    c) Provide structural cell support ✅
    d) Reduce aging signs
    Explanation: Antioxidants do not provide structural support; they reduce oxidative stress.
23. Lycopene is a powerful antioxidant found in:
    a) Apples
    b) Tomatoes ✅
    c) Cucumber
    d) Milk
    Explanation: Lycopene gives tomatoes their red color and fights oxidative stress.
24. Curcumin, found in turmeric, functions as a:
    a) Protein
    b) Carbohydrate
    c) Antioxidant ✅
    d) Mineral
    Explanation: Curcumin is an active antioxidant compound in turmeric.
25. Which vitamin is most sensitive to heat and light, thus easily destroyed?
    a) Vitamin A
    b) Vitamin C ✅
    c) Vitamin D
    d) Vitamin E
    Explanation: Vitamin C degrades quickly when exposed to heat and light.
26. Astaxanthin is an antioxidant found in:
    a) Green vegetables
    b) Red meat
    c) Salmon and shrimp ✅
    d) Milk
    Explanation: Astaxanthin is a red pigment in marine animals with strong antioxidant power.
27. The antioxidant glutathione is composed of which amino acids?
    a) Leucine, isoleucine, valine
    b) Glutamine, glycine, cysteine ✅
    c) Histidine, serine, tyrosine
    d) Alanine, threonine, lysine
    Explanation: These three form glutathione, a key antioxidant.
28. What is the main site of antioxidant defense in the body?
    a) Blood
    b) Skin
    c) Cells ✅
    d) Stomach
    Explanation: Antioxidants act at the cellular level to protect DNA and membranes.
29. Excess intake of antioxidant supplements can cause:
    a) Greater health benefits
    b) Toxicity and cell damage ✅
    c) Faster weight loss
    d) No effect
    Explanation: Over-supplementation may lead to oxidative imbalance.
30. Which antioxidant is synthesized by the body and found in almost every cell?
    a) Vitamin C
    b) Vitamin A
    c) Glutathione ✅
    d) Beta-carotene
    Explanation: Glutathione is the body’s master antioxidant.