Microbiology and the Immune System
Microbes and Host Defense
Types of microbes
Microbiology includes bacteria, archaea, fungi, protists, viruses, and other infectious agents. Some microbes are harmful, many are beneficial, and many are essential to ecosystems and human health.
Innate and adaptive immunity
Innate immunity responds rapidly and broadly through barriers, phagocytes, inflammation, and complement. Adaptive immunity is slower initially but highly specific and includes B cells and T cells.
Immunological memory
Adaptive responses become faster and stronger after exposure because memory cells persist.
Which immune feature is most associated with specificity and memory?
Adaptive immunity generates antigen-specific memory cells.
Correct answer: Adaptive immunity
What is the role of antibodies?
Antibodies are produced by B cells and can block infection or promote immune clearance.
Correct answer: They bind specific antigens and help neutralize pathogens or mark them for destruction.
Innate vs adaptive immunity
| Feature | Innate | Adaptive |
|---|---|---|
| Speed | Fast | Slower at first |
| Specificity | Broad | Highly specific |
| Memory | No true memory | Yes |
| Major cells | Phagocytes, NK cells | B cells, T cells |
Which is a first-line physical barrier against infection?
Skin is a physical barrier that prevents pathogen entry.
Correct answer: Skin