En anglais

Pathogens and the immune system

Science · Organisms & Life Processes · ages 12-14

Name ______________________ Date ____________

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
Which type of pathogen causes the flu?
- Virus
- Bacteria
- Fungus
Some vaccines contain a weakened or dead form of a pathogen.
Circle one: True False
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
Look at this chart of pathogen sizes. Which pathogen is usually the smallest?
- Bacteria
- Fungus
- Virus
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
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
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

Answer key

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

It swallows and digests the pathogen · Engulfing means the white blood cell surrounds the pathogen and digests it.
Virus · The flu is caused by a virus, which is why antibiotics, which target bacteria, do not treat it.
True · That weakened or dead piece cannot give you the disease, but it still trains your immune system.
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.
Virus · Viruses are far smaller than bacteria or fungi, which is one reason they need a host cell to reproduce.
He was infected but not ill · The virus was already in his body before symptoms appeared, so he was infected first and ill later.
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.
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.