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Microbiology · Chapter 10

Portals of Entry & Adhesins

Before a microbe can cause disease it must do two things: reach a portal of entry — a way into the body — and then attach with molecules called adhesins before defenses sweep it away. Tap a portal on the body to see who uses it and how they hold on.

The body's portals

Tap a marker on the body, or a portal in the list.
Portals of entry & adhesinstap a portal to begin
Two steps to start an infectionFirst a microbe must land on a portal of entry; then it must attach to host cells with adhesins — surface molecules that lock onto specific host receptors. No attachment, no infection. Tap a portal to explore each one.
Adhesins sit on fimbriae, pili, capsules, or wall proteins and bind specific host receptors — a lock-and-key fit. Attachment is the required first step of every infection.
The portal of entry often decides the disease. Yersinia pestis causes bubonic plague through a flea bite but deadly pneumonic plague when inhaled — same microbe, different portal.