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Quiz Chapter 4: Human Health

10 questions ยท Form 2 Science Bab 4: Human Health

Question 1 of 10Score: 0

What is an antigen?

Full Question List & Answer Key

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1. What is an antigen?

  1. An antibody produced by white blood cells
  2. A chemical substance or foreign protein on a pathogen that triggers an immune response
  3. A type of medication used to kill viruses
  4. A harmless digestive enzyme
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Answer: B

An antigen is a foreign protein or molecular structure on pathogens that triggers white blood cells to produce specific antibodies.

2. Which of the following diseases is classified as non-infectious?

  1. Cholera
  2. Tuberculosis
  3. Diabetes Mellitus
  4. Dengue Fever
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Answer: C

Diabetes mellitus is caused by genetic factors or lifestyle habits (lack of insulin production/sensitivity) and cannot be transmitted between people.

3. What does a vaccine injected into a person during artificial active immunisation contain?

  1. Ready-made antibodies extracted from horses
  2. Dead or weakened pathogens (antigens)
  3. Antibiotic chemicals
  4. Active digestive enzymes
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Answer: B

Vaccines contain dead, weakened, or fragmented pathogens that trigger the immune system to produce its own antibodies without causing the full-blown disease.

4. Which organ acts as the primary physical barrier in the first line of defence against micro-organisms?

  1. Liver
  2. Intact Skin
  3. Spleen
  4. Kidney
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Answer: B

Intact skin serves as a tough physical and chemical barrier preventing microorganisms from invading internal tissues.

5. What is the primary mechanism utilized by the second line of defence to neutralize pathogens?

  1. Sweat secretion
  2. Phagocytosis by white blood cells
  3. Antibody binding by lymphocytes
  4. Hydrochloric acid secretion in the stomach
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Answer: B

The second line of defence uses non-specific white blood cells (phagocytes) to perform phagocytosis, engulfing and destroying pathogens.

6. A person bitten by a venomous snake is immediately injected with antivenom containing ready-made antibodies. What form of immunity is this?

  1. Artificial Passive Immunity
  2. Natural Active Immunity
  3. Artificial Active Immunity
  4. Natural Passive Immunity
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Answer: A

Injecting manufactured antiserum/antibodies directly into a patient provides immediate protection via artificial passive immunity.

7. Which action helps break the transmission chain of waterborne infectious diseases?

  1. Sleeping under mosquito nets
  2. Boiling water before drinking
  3. Applying sunscreen lotion
  4. Exercising regularly outdoors
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Answer: B

Boiling water kills pathogens like *Vibrio cholerae* and *Salmonella typhi*, preventing waterborne infection.

8. Which factor is a primary cause of non-infectious cardiovascular disease?

  1. Airborne virus transmission
  2. High-fat diet, lack of exercise, and smoking
  3. Bites from Aedes mosquitoes
  4. Consuming unboiled water
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Answer: B

Cardiovascular diseases are non-infectious conditions linked to lifestyle factors like unhealthy diets, smoking, and physical inactivity.

9. Why is active immunity generally longer-lasting than passive immunity?

  1. Active immunity uses stronger external chemicals
  2. Active immunity stimulates memory cells to recognize pathogens in future infections
  3. Passive immunity causes white blood cells to produce permanent toxins
  4. Passive immunity works only in newborn infants
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Answer: B

Active immunity stimulates the body's immune system to generate memory lymphocytes that retain the ability to produce targeted antibodies for years.

10. What happens when an antibody binds to its matching target antigen?

  1. The pathogen is neutralized or clumped together for phagocytosis
  2. The white blood cell turns into a red blood cell
  3. The body loses all natural active immunity
  4. Digestive enzymes in the stomach stop working
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Answer: A

Antibody-antigen binding neutralizes toxins or clumps pathogens (agglutination), making them easier for phagocytes to engulf and digest.

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