Biology

Immunity and microbes

Pathogens, innate and adaptive immunity, antibiotics and vaccines.

Basics

Microbes

Bacteria are prokaryotes; viruses replicate only inside host cells. Fungi and protozoa too. Gram stain tracks the wall. Antibiotics hit bacterial targets (wall, ribosome…), not typical viruses. Resistance is selection.

Immunity

Innate: barriers, phagocytes, inflammation. Adaptive: B-cell antibodies, T cells. Memory is the point of vaccines. MHC displays fragments. Allergy is over-reaction; autoimmunity is mis-recognition.

Formulas

Bacterial doubling (ideal)

N = N₀ · 2^{t / t_d}

Doubling time t_d. Nutrients, waste, and immunity cap real growth.

Symbols

  • t_d doubling time

Key table

Vaccine types (sketch) live-attenuated, inactivated, protein, mRNA, vector, and others

In this field