Pathogen — Science definition
Defined in 2 courses:
- A microorganism or virus that causes disease; whether something acts as one often depends on where it is, as with skin bacteria in a wound. (Life Science & Scientific Inquiry)
- An agent capable of causing disease in a suitable host. (Life Science: Biology)
Where it is taught
- Microorganisms, Barriers & Immune Defense — Coordination, Defense & Reproduction, Life Science & Scientific Inquiry, Grade 7
- Defense, Disease & Homeostasis — Body Systems, Signals & Homeostasis, Life Science: Biology, Grade 10
In use
A pathogen is the much smaller subset that causes disease.
Microorganisms, Barriers & Immune Defense
It is not a guarantee against every infection; protection depends on the vaccine, pathogen and host.
Defense, Disease & Homeostasis
Questions using pathogen
Problem 1
Why should a decomposition bacterium not automatically be labeled a harmful pathogen?
Answer and explanation
Its role depends on organism and context. Decomposition can recycle matter; being microscopic or bacterial does not by itself establish disease-causing activity.
Response criteria
- Explain the relevant biological process accurately.
- Use the supplied evidence and show calculation steps with units where needed.
- Connect a labeled model or mechanism with the claim.
- State an assumption, evidence limitation, or useful next observation.
Problem 2
Why does a changed pathogen antigen sometimes reduce previous protection?
Hints
State what the supplied observations or conditions establish, and separate that from any assumption.
Answer and explanation
Recognition depends on molecular features; altered antigens can reduce the match to existing immune responses.