Biology Notes — Index

Study notes on immunology and molecular biology. Each file is a self-contained summary with a clean logical flow and a ⚠️ Common Pitfalls (易错点) section.

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🧪 Lab Methods & Cell Biology

File	Topic
rna-extraction-trizol.md	Total RNA extraction (TRIzol / acid phenol–chloroform method)
protein-trafficking.md	Protein trafficking and the secretory pathway

🛡️ Innate Immune System (fast, general defense)

File	Topic
complement-system.md	Complement proteins — mark, recruit, and kill invaders
inflammation.md	Inflammation as the universal emergency response
cytokines.md	How cells navigate using chemical signals
dendritic-cell.md	The bridge from innate to adaptive immunity

🎯 Adaptive Immune System (slow, specific, has memory)

File	Topic
vdj-recombination.md	Building billions of receptors from a few gene fragments
t-cell-selection.md	T cell training and selection in the thymus
antigen-presentation.md	Antigen presentation — the hot-dog-bun model (narrative)
mhc-antigen-presentation-pathways.md	MHC I vs II, TCR/CD3, endogenous vs exogenous pathways (technical)

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Suggested Reading Order

Innate defense → loses → calls for backup → Adaptive defense

complement-system → inflammation → cytokines → dendritic-cell
        │
        └──► vdj-recombination → t-cell-selection
                     │
                     └──► antigen-presentation → mhc-antigen-presentation-pathways