How the body defends itself: immunity, vaccines and antibiotics

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   Ari reads a graph for a vaccine at day 0 and a microbe with the same antigen at day 28. Which statement combines what the graph shows with why?

   • The rise after day 28 is slower than after day 0, since the vaccine used up the antibodies
   • The rise after day 28 matches the rise after day 0, since each exposure starts from nothing
   • The level stays near 2 after day 28, since vaccine antibodies already cover the antigen
   • The level reaches 70 within 7 days, above the first peak of 6, since memory cells formed
2. 2.

   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 slow response to both microbes, since each exposure starts from nothing
   • A fast response to microbe P only, since its antigen matches the memory cells
   • A fast response to microbe Q only, since a new antigen wakes the memory cells
   • A fast response to both microbes, since memory cells match any antigen
3. 3.

   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 first, and phagocytes start after 10 days
   • Skin and mucus start after 1 day, and antibodies start after 3 days the first time
   • Antibodies start after 10 days on each exposure, so specific defenses cannot speed up
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
   • 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
   • The same as after dose 1, because memory cells reset after each dose of 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?

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

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

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 4, because a vaccine and an antibiotic do the same job
    • 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

13. Two communities card (model data)

    community	people	immune people
    A	400	200
    B	400	360

14. 9.

    Tala reads a card on two communities. Which statement does the card support?

    • Community A is better protected, since 200 immune people is a smaller number to protect
    • In both communities each immune person is protected alone, so spread is equal
    • Community B is 90 percent immune, so a microbe meets fewer people it can spread to
    • Community B is fully protected, so each person in it is safe from the microbe

15. 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

16. 10.

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

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