Notes
Communicable diseases and immunity
- Communicable diseases are caused by pathogens (bacteria, viruses, fungi, parasites) and spread by contact, droplets, food, water, surfaces and bites. Antibiotics treat bacteria, not viruses.
- The immune system uses barriers, white blood cells and antibodies. Vaccines build immunity safely, and herd immunity protects those who cannot be vaccinated.
- Hygiene: wash hands for 20 seconds, cover coughs, do not share personal items, stay home when sick.
Noncommunicable diseases
- Chronic diseases such as heart disease, type 2 diabetes and cancer do not spread between people. They develop over time and are influenced by genes and behaviors.
- Risk factors can be controllable (tobacco, inactivity, sun exposure) or not (age, heredity). Prevention includes balanced eating, activity, sleep, no tobacco, sunscreen and regular checkups.
Topics in this unit
Each topic has its own short notes and practice.
Practice
Viruses are pathogens.
Antibiotics work only on bacteria.
Antibodies bind to and help eliminate pathogens.
Heart disease does not spread person to person.
Sun protection is the main prevention.
Behaviors can reduce risk.
Free response
Write your answer first, then open the scoring guide.
Free-response question
A school has an outbreak of the flu. Noah is feeling feverish and has a cough, and his older grandmother lives at home with him. Noah's family has not had flu shots this year.
(a) Explain how a flu shot could have helped protect Noah and his grandmother.
Show the answer and scoring guide
A flu shot trains the immune system to make antibodies so Noah is less likely to get sick or has a milder illness, and fewer germs spread to his grandmother.
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(b) Give two hygiene actions Noah should take now.
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He should stay home, wash his hands for 20 seconds often and cover his cough with his elbow or a tissue. He should not share cups.
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(c) Noah asks if he should ask for antibiotics. Is that appropriate? Explain.
Show the answer and scoring guide
No. The flu is caused by a virus, and antibiotics treat only bacterial infections. A doctor can advise on rest, fluids and any antiviral medicine.
Check off the points you earned: