Pathogens & the Immune System · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Pathogens and the immune system

Science · Organisms & Life Processes · ages 12-14
Name ______________________   Date ____________

  1. What happens when a white blood cell engulfs a pathogen?

    • It turns the pathogen into a vaccine
    • It swallows and digests the pathogen
    • It pushes the pathogen out through sweat

  2. Which type of pathogen causes the flu?

    • Virus
    • Bacteria
    • Fungus

  3. Some vaccines contain a weakened or dead form of a pathogen.

    Circle one:   True   False

  4. What is an antibody's job?

    • Lock onto one specific pathogen and mark it for destruction
    • Attack every pathogen in the body, not just one
    • Engulf and digest the pathogen directly

  5. Look at this chart of pathogen sizes. Which pathogen is usually the smallest?

    Virus100Bacteria2000Fungus5000
    • Bacteria
    • Fungus
    • Virus

  6. Leo picks up a stomach bug virus on Monday. He feels completely fine until Wednesday, when his stomach starts hurting. What was true on Monday and Tuesday?

    • He was ill but not infected
    • He was infected but not ill
    • He was neither infected nor ill

  7. A student says engulfing a pathogen and making antibodies are the exact same thing. What is wrong with that statement?

    • Engulfing destroys it while antibodies mark it
    • Antibodies are made by bacteria, not by the body
    • White blood cells never actually touch a pathogen

  8. After getting a flu vaccine, Priya still catches a bad cold two weeks later. Did the vaccine fail?

    • Yes, because a vaccine should prevent every illness
    • No, because vaccines only protect you for one week
    • No, because colds are caused by different viruses than the ones the flu vaccine targets
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Pathogens and the immune system W1-mt_1VIE8FlZvL-s1

  1. It swallows and digests the pathogen · Engulfing means the white blood cell surrounds the pathogen and digests it.
  2. Virus · The flu is caused by a virus, which is why antibiotics, which target bacteria, do not treat it.
  3. True · That weakened or dead piece cannot give you the disease, but it still trains your immune system.
  4. Lock onto one specific pathogen and mark it for destruction · Each antibody is shaped to match one specific pathogen, not every germ in the body.
  5. Virus · Viruses are far smaller than bacteria or fungi, which is one reason they need a host cell to reproduce.
  6. He was infected but not ill · The virus was already in his body before symptoms appeared, so he was infected first and ill later.
  7. Engulfing destroys it while antibodies mark it · Both are jobs of white blood cells, but engulfing destroys the pathogen on the spot, while antibodies tag a specific pathogen for the immune system to deal with.
  8. No, because colds are caused by different viruses than the ones the flu vaccine targets · A flu vaccine trains the immune system for flu viruses specifically, not for the many different viruses that cause colds.
Worksheet · LightMySky