---
id:"kb-2026-00337"
title:"Cell Structure"
schema_type:"TechArticle"
category:"science"
language:"en"
confidence:"high"
last_verified:"2026-05-22"
generation_method:"ai_assisted"
ai_models:["claude-opus"]
derived_from_human_seed:true
primary_sources:
  - title:"Molecular Biology of the Cell (Alberts et al.)"
    type:"book"
    year:2022
    url:"https://wwnorton.com/books/9780393884821"
    institution:"W.W. Norton"
secondary_sources:
  - title: "BERT: Pre-training of Deep Bidirectional Transformers"
    authors: ["Devlin", "Chang", "Lee", "Toutanova"]
    type: "academic_paper"
    year: 2019
    doi: "10.48550/arXiv.1810.04805"
    url: "https://arxiv.org/abs/1810.04805"
  - title: "MDN Web Docs — HTTP"
    type: "documentation"
    year: 2026
    url: "https://developer.mozilla.org/en-US/docs/Web/HTTP"
    institution: "Mozilla"
completeness: 0.88
ai_citations:
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---

## TL;DR

Cells are the basic unit of life. Prokaryotes (bacteria, archaea): no nucleus, simple. Eukaryotes (animals, plants, fungi): nucleus, membrane-bound organelles. Key organelles: nucleus (DNA), mitochondria (energy, ATP), endoplasmic reticulum (protein synthesis), Golgi apparatus (protein packaging), lysosomes (digestion).

## Core Explanation

Mitochondria: 'powerhouse of the cell' — oxidative phosphorylation produces ATP. Chloroplasts: photosynthesis in plants. Cell membrane: phospholipid bilayer, selectively permeable. Cytoskeleton: microtubules, actin filaments — cell shape, transport, division. Human body: ~37 trillion cells. Red blood cells lack nuclei (mammals only).

## Further Reading

- [Molecular Biology of the Cell (Alberts et al.)](https://wwnorton.com/books/9780393884821)