How the body defends itself: immunity, vaccines and antibiotics
Grade 9 Science Worksheet - Challenge Me

Circle the best answer.
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 level stays near 2 after day 28, since vaccine antibodies already cover the antigen
- The rise after day 28 matches the rise after day 0, since each exposure starts from nothing
- The rise after day 28 is slower than after day 0, since the vaccine used up the antibodies
- The level reaches 70 within 7 days, above the first peak of 6, since memory cells formed
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 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 P only, since its antigen matches the memory cells
- A fast response to microbe Q only, since a new antigen wakes the memory cells
Jun reads a shape card. A microbe's surface changes from antigen X to a new antigen Z. Which prediction fits the next response?
Shape card (model data), 2 rows. Columns: antigen, tip shape, fits the memory cells' antibodies. old antigen X, triangle, yes. new antigen Z, square, no. Shape card (model data), 2 rows. Columns: antigen, tip shape, fits the memory cells' antibodies. old antigen X, triangle, yes. new antigen Z, square, no. antigen tip shape fits the memory cells' antibodies old antigen X triangle yes new antigen Z square no Shape card (model data), 2 rows. - A fast, high rise like a second exposure, because memory cells' antibodies fit any tip
- 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
- No rise, because the first response cleared that microbe from the body for good
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?
Model graph of antibody level after a first vaccine dose (model data). Time since the first dose (days) across, 0 to 42, a mark every 7. Antibody level (arbitrary units) up, 0 to 40, a mark every 10. Antibody level joins (0, 0), (7, 2), (14, 8), (21, 5), (28, 3). A second dose of the same vaccine is given at day 28. Model graph of antibody level after a first vaccine dose (model data). Time since the first dose (days) across, 0 to 42, a mark every 7. Antibody level (arbitrary units) up, 0 to 40, a mark every 10. Antibody level joins (0, 0), (7, 2), (14, 8), (21, 5), (28, 3). A second dose of the same vaccine is given at day 28. Model graph of antibody level after a first vaccine dose (model data) 0 7 14 21 28 35 42 0 10 20 30 40 Time since the first dose (days) Antibody level (arbitrary units) A second dose of the same vaccine is given at day 28 - Higher than after dose 1, because dose 2 delivers ready-made antibodies
- 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
- Lower than after dose 1, because the first dose used up the antigen in the vaccine
Read this first
Community card (model data)
time people immune people before 500 250 after 500 450 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 are fully protected, because 450 of 500 is enough to stop the microbe completely
- No change for them, because protection stays with each immune person alone
- 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
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.
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 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
- Line 1, because skin and mucus are second-line defenses that act after the antibodies
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.
Noah reviews a classmate's notebook on vaccines. Exactly one line is wrong. Which line, and why?
- Line 4, because the body makes its own antibodies after a vaccine
- Line 3, because a vaccine cannot lead to memory cells
- Line 1, because a vaccine contains no antigen
- Line 2, because the vaccine supplies the antibodies, not the B cells
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.
Pia reviews a classmate's notebook on antibiotics. Exactly one line is wrong. Which line, and why?
- Line 1, because antibiotics treat any kind of germ
- Line 2, because antibiotics do not work on viruses
- Line 4, because a vaccine and an antibiotic do the same job
- Line 3, because resistance is a trait of people, not of bacteria
Two communities card (model data)
community people immune people A 400 200 B 400 360 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
- Community B is fully protected, so each person in it is safe from the microbe
- 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
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 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 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