Test – 12.3 Immunity

SECTION A: MULTIPLE CHOICE QUESTIONS #

1. What is active immunity?

   A. Defence against disease by receiving antibodies from another person

   B. Defence against a pathogen by antibody production in the body

   C. Defence by using medicine to kill pathogens

   D. Defence by avoiding contact with pathogens

2. What are antigens?

   A. Proteins produced by the body to fight disease

   B. White blood cells that destroy pathogens

   C. Substances on pathogens that have specific shapes

   D. Weakened forms of pathogens used in vaccines

3. Which statement correctly describes antibodies?

   A. They are cells that engulf and destroy pathogens

   B. They are proteins that bind to antigens on pathogens

   C. They are substances found on the surface of pathogens

   D. They are weakened pathogens used in vaccination

4. Why can a specific antibody only bind to one type of antigen?

   A. Because antibodies are too small to bind to multiple antigens

   B. Because antibodies are destroyed after binding once

   C. Because antibodies have complementary shapes that fit specific antigens

   D. Because antibodies can only be produced once in the body

5. How can active immunity be gained?

   A. Only by vaccination

   B. Only by infection with a pathogen

   C. By receiving antibodies from mother’s milk

   D. By infection with a pathogen or by vaccination

6. What happens first during vaccination?

   A. Memory cells produce antibodies immediately

   B. Weakened pathogens or their antigens are given

   C. The immune system is permanently destroyed

   D. Passive immunity is developed

7. Which cells are responsible for producing antibodies during vaccination?

   A. Red blood cells

   B. Phagocytes

   C. Lymphocytes

   D. Memory cells only

8. What is the main advantage of memory cells produced during vaccination?

   A. They provide short-term immunity only

   B. They give long-term immunity against the pathogen

   C. They kill pathogens directly

   D. They prevent all diseases from entering the body

9. How does vaccination help control the spread of transmissible diseases?

   A. It kills all pathogens in the environment

   B. It makes pathogens weaker

   C. It reduces the number of people who can catch and spread the disease

   D. It provides passive immunity to everyone

10. What is passive immunity?

    A. Long-term defence by producing your own antibodies

    B. Defence by avoiding pathogens completely

    C. Short-term defence by receiving antibodies from another individual

    D. Defence by taking antibiotics

11. How does a baby receive passive immunity from its mother?

    A. Only through breast milk

    B. Only across the placenta before birth

    C. Across the placenta and through breast milk

    D. By sharing the same air

12. Why is breast-feeding important for infant immunity?

    A. It helps the baby produce memory cells

    B. It provides antibodies that give passive immunity

    C. It gives the baby active immunity

    D. It prevents all diseases permanently

13. What is the main difference between active and passive immunity?

    A. Active immunity produces memory cells, passive immunity does not

    B. Passive immunity lasts longer than active immunity

    C. Active immunity comes from another person, passive immunity does not

    D. Passive immunity produces antibodies, active immunity does not

14. How does HIV affect the immune system?

    A. It increases the number of red blood cells

    B. It decreases lymphocyte numbers and reduces antibody production

    C. It strengthens the immune system over time

    D. It only affects memory cells

15. Why do people with HIV become more vulnerable to other infections?

    A. Because HIV destroys all antibodies in the body

    B. Because the weakened immune system cannot fight pathogens effectively

    C. Because HIV prevents vaccination from working

    D. Because HIV increases the number of pathogens in the body

SECTION B: WRITTEN RESPONSE QUESTIONS #

1. Explain what happens when a pathogen enters the body for the first time.

   1. State what antigens are and where they are found. [2 marks]
   2. Describe how the immune system responds to these antigens. [3 marks]
   3. Explain why the immune response takes several days during a first infection. [2 marks]

2. A student says: “Antibodies and antigens are the same thing.”

   1. Explain why this statement is incorrect. [3 marks]
   2. Describe how antibodies and antigens work together in the immune response. [3 marks]

3. The diagram shows what happens during vaccination.

   
   1. Explain why weakened pathogens are used in vaccines instead of strong, active pathogens. [2 marks]
   2. Describe the role of lymphocytes in vaccination. [2 marks]
   3. Explain how memory cells provide long-term immunity. [3 marks]

4. Complete the table comparing active and passive immunity.

   Feature	Active Immunity	Passive Immunity
   How antibodies are obtained	_____________	_____________
   Examples of how immunity is gained	_____________	_____________
   Are memory cells produced?	_____________	_____________
   How long does immunity last?	_____________	_____________

5. A mother asks why she should breast-feed her newborn baby.

   1. Explain what type of immunity breast milk provides to the baby. [1 mark]
   2. Describe how this immunity helps protect the baby. [2 marks]
   3. Explain why this type of immunity is only temporary. [2 marks]

6. A community has a measles outbreak. Some children are vaccinated against measles while others are not.

   1. Explain why vaccinated children are less likely to catch measles. [3 marks]
   2. Describe how vaccination of many people in the community helps protect those who cannot be vaccinated. [3 marks]

7. The graph shows antibody levels in the blood after infection and re-infection with the same pathogen.

   

    

   1. Describe the difference in antibody production between the first and second infection. [2 marks]
   2. Explain why the second response is faster and stronger. [3 marks]
   3. State what type of immunity this represents. [1 mark]

8. HIV is a virus that affects the immune system.

   1. Describe how HIV weakens the immune system. [3 marks]
   2. Explain why people with HIV are more likely to die from other infections rather than from HIV itself. [3 marks]

9. A scientist is developing a new vaccine for a disease.

   1. State two things that must be included in the vaccine. [2 marks]
   2. Explain why the vaccine must contain antigens from the specific pathogen. [2 marks]
   3. Describe what should happen in the body after the vaccine is given. [3 marks]

10. Two students are discussing immunity. Student A says: “Once you have antibodies for a disease, you can never catch that disease again.” Student B says: “That’s not always true.”

    1. Explain when Student A would be correct. [2 marks]
    2. Explain when Student B would be correct. [2 marks]
    3. Use your knowledge of memory cells to support both answers. [3 marks]