How the body defends itself: immunity, vaccines and antibiotics

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   Microbe card (model data), 2 rows. Columns: microbe, antigen on its surface. P, X. Q, Y. Bo reads a microbe card. A vaccine with antigen X was given earlier, and antigen Y is not similar to X. Which statement fits both microbes?

   • A fast response to microbe P only, since its antigen matches the memory cells
   • A fast response to both microbes, since memory cells match any antigen
   • A slow response to both microbes, since each exposure starts from nothing
   • A fast response to microbe Q only, since a new antigen wakes the memory cells
2. 2.

   Esme reads a defense timing card. Which statement combines the lines of defense with the timing on the card?

   • Phagocytes start after 1 day, and antibodies start sooner on a repeat exposure
   • Antibodies start after 10 days on each exposure, so specific defenses cannot speed up
   • Skin and mucus start after 1 day, and antibodies start after 3 days the first time
   • Antibodies start first, and phagocytes start after 10 days
3. 3.

   Jun reads a shape card. A microbe's surface changes from antigen X to a new antigen Z. Which prediction fits the next response?

   • No rise, because the first response cleared that microbe from the body for good
   • A slow, low rise like a first exposure, since the antibodies do not fit square tips
   • A fast, high rise, because the microbe is still the same kind of microbe as before
   • A fast, high rise like a second exposure, because memory cells' antibodies fit any tip
4. 4.

   Kira reads a graph for one vaccine dose at day 0. In the model, a second dose is given at day 28. Which prediction fits the response after it?

   • Higher and faster than after dose 1, because dose 2 acts like a second exposure
   • The same as after dose 1, because memory cells reset after each dose of the vaccine
   • Higher than after dose 1, because dose 2 delivers ready-made antibodies
   • Lower than after dose 1, because the first dose used up the antigen in the vaccine

5. Read this first

   Community card (model data)

   time	people	immune people
   before	500	250
   after	500	450

6. 5.

   Luz reads a community card. Immune people rise from 250 to 450 of 500. Which prediction fits people in the community who are not immune?

   • No change for them, because protection stays with each immune person alone
   • They are fully protected, because 450 of 500 is enough to stop the microbe completely
   • They meet fewer people who can pass it on, though protection is not complete
   • They become immune too, because immunity passes from person to person on contact

7. Use this

   Notebook (model data), 4 rows. Columns: line, what it says. 1, Skin and mucus are barriers at the body surface. 2, Antibodies are first-line defenses that act within minutes. 3, Inflammation, fever and phagocytes make up the second line. 4, Memory cells let a second response start sooner.

8. 6.

   Milo reviews a classmate's notebook on the lines of defense. Exactly one line is wrong. Which line, and why?

   • Line 4, because memory cells make a second response slower than the first one
   • Line 1, because skin and mucus are second-line defenses that act after the antibodies
   • Line 3, because phagocytes and inflammation are part of the first line, not the second
   • Line 2, because antibodies are specific defenses that take days the first time

9. Use this

   Notebook (model data), 4 rows. Columns: line, what it says. 1, A vaccine contains an antigen from a microbe. 2, After a vaccine, the body's own B cells make antibodies. 3, Memory cells can make a later response faster. 4, A vaccine gives the person ready-made antibodies.

10. 7.

    Noah reviews a classmate's notebook on vaccines. Exactly one line is wrong. Which line, and why?

    • Line 1, because a vaccine contains no antigen
    • Line 2, because the vaccine supplies the antibodies, not the B cells
    • Line 4, because the body makes its own antibodies after a vaccine
    • Line 3, because a vaccine cannot lead to memory cells

11. Use this

    Notebook (model data), 4 rows. Columns: line, what it says. 1, Antibiotics treat certain infections caused by bacteria. 2, Antibiotics work on the viruses that cause a cold or the flu. 3, Bacteria that survive an antibiotic can multiply and spread their resistance. 4, A vaccine prepares memory cells, which is different from what an antibiotic does.

12. 8.

    Pia reviews a classmate's notebook on antibiotics. Exactly one line is wrong. Which line, and why?

    • Line 2, because antibiotics do not work on viruses
    • Line 1, because antibiotics treat any kind of germ
    • Line 3, because resistance is a trait of people, not of bacteria
    • Line 4, because a vaccine and an antibiotic do the same job
13. 9.

    Ren reads a graph of antibody level after exposures at day 0 and day 28. Which statement does the graph support?

    • The second peak, 100, was 10 times the first peak, 10, and came sooner after its exposure
    • The second peak, 100, matched the first peak, and came sooner after its exposure
    • The second peak, 100, was 90 times the first peak, 10, and came sooner after its exposure
    • The second peak, 100, was 10 times the first peak, 10, but came later after its exposure

14. Bacteria count card (model data)

    step	bacteria	bacteria with the resistance trait
    before the antibiotic	1,000	10
    just after the antibiotic	10	10
    after regrowth	640	640

15. 10.

    Zee reads a count card for bacteria and one antibiotic. Which statement does the card support?

    • The 10 bacteria that remained had the trait before the antibiotic and then multiplied
    • The person's own cells became resistant to the antibiotic, so 640 bacteria grew back
    • The antibiotic cleared the viruses too, so just the bacteria with the trait were left
    • The antibiotic gave the resistance trait to the 10 bacteria that remained in the sample