Diseases & Immunity

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선생님을 위해: Diseases & Immunity(Biology, CIE)을(를) 위한 바로 쓸 수 있는 수업 슬라이드, 복습 노트, 다이어그램 — 수업에 사용하거나, 학생들이 실시간 게임으로 즐기는 인터랙티브 클래스 활동으로 진행하세요.

수업 노트

Pathogens & Barriers

A pathogen is a disease-causing organism (e.g. bacterium, virus, fungus).
Diseases caused by pathogens are transmissible – passed from host to host.
Transmission can be direct (body fluids: HIV, gonorrhoea) or indirect (air droplets, contaminated food/water, vectors like mosquitoes).
Mechanical barriers: skin (blocks entry, heals with scab), hairs in nose (trap pathogens).
Chemical barriers: mucus (traps pathogens, removed by coughing/swallowing), stomach acid (HCl kills pathogens).
Cellular defences: white blood cells – phagocytes engulf pathogens (phagocytosis); lymphocytes produce antibodies.

Methods of Transmission

Controlling the Spread of Disease

Clean water supply prevents waterborne diseases like cholera.
Hygienic food preparation (washing hands, proper cooking) reduces contamination.
Personal hygiene (soap, tissues for sneezes/coughs) limits colds and flu.
Waste disposal (sealed bins) reduces vectors like flies.
Sewage treatment removes pathogens before release into environment.

Preventing the Spread of Disease

Active Immunity (Extended)

Active immunity: body makes its own antibodies and memory cells after exposure to a pathogen or vaccination.
Slow-acting but provides long-lasting protection.
Can be acquired naturally (infection) or artificially (vaccination).

Antigens & Antibodies (Extended)

Antigens are molecules (e.g. proteins) on cell surfaces; they are unique to each individual/pathogen.
Lymphocytes recognise foreign antigens and produce antibodies – proteins complementary in shape to the antigen.
Antibodies cause agglutination (clumping) of pathogens, making them easier for phagocytes to engulf.
Memory cells remain after infection; on reinfection, they trigger rapid antibody production – person is immune.
Some pathogens mutate and change antigens, so memory cells may not recognise them.

Lymphocytes produce antibodies specific to an antigen

Vaccination (Extended)

Vaccines contain a dead or weakened form of a pathogen (with antigens) that cannot cause disease.
They stimulate lymphocytes to produce antibodies and memory cells without causing illness.
Vaccination gives active immunity – long-lasting protection.
Herd immunity: when a high % of the population is vaccinated, the pathogen has few hosts, protecting the unvaccinated.
Smallpox was eradicated in 1980 by a global vaccination programme.

How a vaccine produces long-term immunity

Passive Immunity & Breastfeeding

Passive immunity: antibodies are acquired from another individual – fast-acting but short-term (no memory cells).
Antibodies pass from mother to infant via breast milk (colostrum), protecting the baby until its own immune system matures.
The body does not produce its own antibodies or memory cells in passive immunity.

Cholera

Cholera is caused by Vibrio cholerae bacteria, transmitted via contaminated water/food.
Bacteria attach to the small intestine and produce a toxin.
The toxin stimulates intestinal cells to release chloride ions into the gut lumen.
Lower water potential in the gut causes water to move out of cells by osmosis, leading to severe diarrhoea.
Loss of water and ions can be fatal; treated with oral rehydration therapy (salt and sugar solution).

How cholera leads to diarrhoea

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연습 문제

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1.What is a pathogen?
Easy
- AA disease-causing organism
- BA transmissible disease
- CA phagocyte that engulfs bacteria
- DA bacterial cell
2.The immune system recognises which part of a pathogen?
Easy
- AAntibiotic
- BAntigen
- CActive site
- DAntibody
3.Which body defence listed below acts as a chemical barrier?
Easy
- AMucus lining the airways
- BAntibody production
- CHairs in the nose
- DPhagocytosis
4.Which of the options below is an example of a transmissible disease?
Easy
- AObesity
- BTooth decay
- CCholera
- DRickets
5.Which cells produce mucus?
Easy
- ACiliated cells
- BGoblet cells
- CNerve cells
- DWhite blood cells
6.The human body has a number of barriers to prevent infection by pathogens. Which of these are examples of mechanical barriers? 1. Skin 2. Mucus 3. Hairs in the nose 4. Antibodies 5. Stomach acid
Easy
- A1 and 3
- B1, 2 and 4
- C2 and 4
- D1, 3 and 5
7.Which of the following diseases listed below are not caused by infectious pathogens? 1. Coronary Heart Disease 2. Cholera 3. AIDS 4. Scurvy
Easy
- A2 only
- B1 and 4
- C2 and 3
- D2, 3 and 4
8.Which of the following is an effect of a cholera infection? 1. Loss of salts from the blood 2. Loss of water from the blood 3. Blockage of the small intestine 4. Persistent diarrhoea
Easy
- A1 and 4
- B1, 2 and 4
- C3 and 4
- DAll 4

더 많은 문제

9.Statements 1 to 4 describe stages in the development of cholera. 1. Chloride ions are secreted into the gut. 2. Osmosis causes water to move into the gut. 3. The infected person becomes dehydrated. 4. Toxins are produced by the pathogenic bacteria. What is the correct sequence of the four stages?
Medium
- A1 → 2 → 3 → 4
- B1 → 4 → 3 → 2
- C4 → 1 → 2 → 3
- D4 → 1 → 3 → 2
10.Which of the following is a correct definition for the term transmissible disease?
Easy
- Aa disease caused by a pathogen that can be passed from one host to another
- Ba disease caused by a pathogen that cannot be treated with antibiotics
- Ca disease that is always transmitted through direct contact between individuals
- Da disease caused by unhealthy lifestyle choices that increase the risk of infection
11.Passive and active immunity have which of the following features in common? 1. They are always long-term. 2. They always involve the activity of memory cells. 3. They involve antibodies. 4. They can be acquired by vaccination.
Medium
- A1 and 2
- B3 only
- C2 and 3
- D3 and 4
12.Varicella zoster virus (VZV) causes chickenpox. The graph shows the concentration of antibodies in the blood of a patient after vaccination against VZV. What most likely happened at point X to cause the increase in antibody concentration?
Medium
- Ainfection with a different pathogen
- Bthe vaccine took time to stimulate lymphocytes
- Cantibodies produced earlier were released into the blood
- Dinfection with the VZV
13.A child is vaccinated against measles. A few years later, the child is exposed to the measles virus. The graph shows the concentration of measles antibodies in the child’s blood over time. Which statement is consistent with the information in the graph?
Medium
- AAfter vaccination, the child produced memory cells.
- BThe child had passive immunity against measles.
- CThe measles virus contains antibodies.
- DThe vaccination failed to protect the child against measles.
14.Which row in the table correctly describes the attributes of passive immunity? | Row | Effective period | Antibodies made by the body? | Memory cells produced? | |---|---|---|---| | A | long term | yes | no | | B | long term | yes | yes | | C | short term | no | no | | D | short term | no | yes |
Medium
- AA
- BB
- CC
- DD
15.The diagram shows a bacterium with proteins on its surface (X). The diagram also shows proteins made by the human body (Y). Which row shows the correct combination for destroying the bacterium?
Medium
- AX are antigens, Y are antibodies
- BX are antibodies, Y are antigens
- CX are pathogens, Y are phagocytes
- DX are toxins, Y are antitoxins
16.Which of the following diseases can be transmitted by contact with contaminated surfaces?
Medium
- AAthlete's foot and malaria
- BSalmonella and typhoid
- CInfluenza and dengue fever
- DSalmonella and athlete's foot
17.The graph shows the response of the body to vaccination. What should replace the letter X on the y-axis label?
Easy
- AAntibody concentration
- BAntigen concentration
- CPathogen concentration
- DPlatelet concentration
18.A tissue is transplanted from a female donor to a male recipient and is rejected. What is the main cause of this rejection?
Medium
- AThe presence of an X chromosome
- BThe action of platelets
- CThe action of antibiotics
- DAntibody production
19.A population of 1000 people is exposed to a new infectious disease. 800 are vaccinated, 200 are not. The vaccine is 90% effective. If the disease has a basic reproduction number (R0) of 4, what is the approximate percentage of the population that is immune?
Hard
- A72%
- B80%
- C90%
- D100%
20.The diagram shows a bacterium with surface proteins X and human antibodies Y. Which row correctly describes how the antibodies destroy the bacterium?
Medium
- AAntibodies bind to antigens, causing agglutination and signalling phagocytes.
- BAntibodies engulf the bacterium directly.
- CAntibodies produce toxins that kill the bacterium.
- DAntibodies replicate inside the bacterium.
21.A population of 1000 people is exposed to a new infectious disease. 800 are vaccinated, 200 are not. The vaccine is 90% effective. If the disease has a basic reproduction number (R0) of 5, what is the minimum percentage of the population that must be immune to achieve herd immunity?
Hard
- A80%
- B90%
- C70%
- D85%
22.Which of the following is a correct sequence of events in the development of cholera symptoms?
Medium
- ABacteria attach to intestine → produce toxin → chloride ions released into gut → water moves into gut by osmosis → diarrhoea
- BBacteria produce toxin → bacteria attach to intestine → water moves into gut → chloride ions released → diarrhoea
- CChloride ions released → bacteria attach → toxin produced → water moves into gut → diarrhoea
- DWater moves into gut → bacteria attach → toxin produced → chloride ions released → diarrhoea
23.Which of the following is a mechanical barrier to pathogen entry?
Easy
- AHairs in the nose
- BMucus
- CStomach acid
- DAntibodies
24.The graph shows antibody concentration after vaccination. At point X, antibody concentration increases sharply. What is the most likely cause?
Medium
- AInfection with the same pathogen
- BThe vaccine finally taking effect
- CAntibodies from another source entering the blood
- DA second vaccination dose
25.Which disease can be transmitted by contaminated food or water?
Easy
- ACholera
- BInfluenza
- CHIV
- DAthlete's foot
26.In an experiment to measure the effect of vaccination on antibody production, a group of mice is vaccinated and another group is not. Both groups are later exposed to the pathogen. Which graph would show the expected antibody response?
Medium
- AVaccinated group shows a rapid, high antibody peak; unvaccinated shows a slower, lower peak.
- BBoth groups show identical antibody responses.
- CUnvaccinated group shows a rapid peak; vaccinated shows no response.
- DVaccinated group shows no antibodies; unvaccinated shows a slow rise.
27.Which of the following is a correct definition of passive immunity?
Easy
- AShort-term immunity gained by receiving antibodies from another individual.
- BLong-term immunity gained by producing antibodies after infection.
- CImmunity gained by vaccination with dead pathogens.
- DImmunity that involves memory cell production.
28.A vaccine contains weakened pathogens. Why are weakened pathogens used instead of dead ones?
Medium
- AWeakened pathogens can still replicate slightly, provoking a stronger immune response without causing disease.
- BDead pathogens cannot stimulate antibody production.
- CWeakened pathogens are easier to produce.
- DDead pathogens may mutate and become harmful.
29.Which type of white blood cell is responsible for producing antibodies?
Easy
- ALymphocyte
- BPhagocyte
- CNeutrophil
- DErythrocyte
30.What is the name of the molecule on the surface of a pathogen that triggers an immune response?
Easy
- AAntibody
- BAntigen
- CAntitoxin
- DPathogen
31.Which of the following is an example of a transmissible disease?
Easy
- AObesity
- BCholera
- CRickets
- DCoronary heart disease
32.The diagram shows a bacterium with surface proteins (X) and human antibodies (Y). Which row correctly describes how the antibodies destroy the bacterium? (Diagram: icon_scene with bacterium icon, labels X on surface proteins, Y on Y-shaped antibody icons near bacterium)
Medium
- AAntibodies attach to antigens and cause agglutination
- BAntibodies engulf the bacterium
- CAntibodies produce toxins that kill the bacterium
- DAntibodies stimulate the bacterium to self-destruct
33.Which row correctly describes passive immunity?
Medium
- AShort-term, no antibody production by the body, no memory cells
- BLong-term, antibody production by the body, memory cells formed
- CShort-term, antibody production by the body, memory cells formed
- DLong-term, no antibody production by the body, memory cells formed
34.The graph shows antibody concentration after vaccination. At point X, antibody concentration increases sharply. What is the most likely cause? (Diagram: icon_scene showing a line graph with axes: time on x-axis, antibody concentration on y-axis; curve rises after vaccination, then a sharp rise at point X labelled 'second exposure')
Medium
- AInfection with the same pathogen
- BThe vaccine took time to stimulate lymphocytes
- CAntibodies produced earlier were released into the blood
- DInfection with a different pathogen
35.Which of the following is a correct sequence of events in an immune response to a pathogen?
Hard
- ALymphocyte recognises antigen → lymphocyte produces antibody → antibody binds to antigen → phagocyte engulfs pathogen
- BPhagocyte engulfs pathogen → lymphocyte produces antibody → antibody binds to antigen → memory cells formed
- CAntibody binds to antigen → phagocyte engulfs pathogen → lymphocyte produces antibody → memory cells formed
- DLymphocyte produces antibody → antibody binds to antigen → lymphocyte recognises antigen → phagocyte engulfs pathogen
36.Which type of white blood cell engulfs and digests pathogens?
Easy
- ALymphocyte
- BPhagocyte
- CPlatelet
- DRed blood cell
37.What is the name of the disease-causing organism that can be transmitted from one host to another?
Easy
- APathogen
- BAntibody
- CAntigen
- DToxin
38.Which of the following is a mechanical barrier that helps prevent pathogens from entering the body?
Easy
- AMucus
- BStomach acid
- CSkin
- DWhite blood cells
39.Antibodies are produced by phagocytes.
Easy
True or false?
40.Which of the following correctly describes how cholera bacteria cause diarrhoea?
Hard
- AThey produce a toxin that stimulates chloride ion secretion into the small intestine, lowering water potential and causing water to move into the intestine by osmosis.
- BThey block the small intestine, preventing water absorption.
- CThey produce a toxin that directly damages the lining of the large intestine.
- DThey increase the rate of peristalsis, speeding up food passage.
41.Vaccination provides protection against disease by:
Easy
- AIntroducing dead or weakened pathogens that stimulate the production of memory cells.
- BInjecting antibodies directly into the bloodstream.
- CKilling all pathogens in the body immediately.
- DProviding a physical barrier against pathogen entry.
42.Passive immunity is long-lasting because the body produces its own memory cells.
Easy
True or false?
43.Match each term on the left with its correct description on the right.
Medium
- Antigen
- Antibody
- Antitoxin
- A protein that neutralises bacterial toxins
- A molecule on the surface of a cell that triggers an immune response
- A protein produced by lymphocytes that binds to antigens
44.Place the following steps in the correct order for how cholera causes diarrhoea.
Medium
- Water moves into the intestine by osmosis.
- Cholera bacteria attach to the wall of the small intestine.
- Chloride ions accumulate in the lumen, lowering water potential.
- The toxin stimulates cells to release chloride ions.
- Large quantities of water are lost in watery faeces.
45.Which of the following are examples of chemical barriers used by the body to defend against pathogens? (Select all that apply)
Medium
- AMucus
- BSkin
- CStomach acid
- DHairs in the nose
- EWhite blood cells
46.Match each body defence on the left with its correct type on the right.
Easy
- Skin
- Mucus
- Stomach acid
- White blood cells
- Mechanical barrier
- Chemical barrier
- Chemical barrier
- Cellular defence
47.Complete the sentence.
Easy
The type of white blood cell that engulfs and digests pathogens is called a ____.
48.In a population of 1000 people, 800 are vaccinated against a disease. The vaccine is 90% effective. If the disease has a basic reproduction number (R0) of 4 in an unvaccinated population, what is the effective reproduction number (R) in this population? Give your answer to one decimal place.
Hard
49.Explain why a person who recovers from a disease such as chickenpox is usually immune to that disease for life, but may still get a cold caused by a different virus.
Medium
50.In a population of 1000 people, 800 are vaccinated against a disease. The vaccine is 90% effective. If the disease has a basic reproduction number (R0) of 4 in an unvaccinated population, what is the effective reproduction number (R) in this population? Give your answer to one decimal place.
Hard
- A1.1
- B0.8
- C1.8
- D2.8

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