Membranes · compartments · traffic · energy · signaling · division

Cytology

Study cells as organized living systems. Cytology connects membranes, compartments, molecular machinery, cytoskeleton, transport, energy conversion, signaling, growth, division, and experimental evidence across many scales.

Primary navigation · cell systems index

A cell is not a bag of tiny departments. It is an interacting physical system.

The confocal-style world behind the page shows one generalized animal-cell slice with membrane, nucleus, rough ER, Golgi, mitochondria, microtubule tracks, and a single slow transport carrier. The composition is deliberately schematic, but its relationships are biologically grounded.

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Membranes & Transport

Study lipid bilayers, membrane proteins, diffusion, osmosis, channels, carriers, pumps, electrochemical gradients, endocytosis, exocytosis, and selective transport.

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Organelles & Compartments

Study the nucleus, endoplasmic reticulum, Golgi apparatus, mitochondria, lysosomes, peroxisomes, vesicles, and how compartment boundaries organize cellular chemistry.

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Cytoskeleton & Motility

Study actin filaments, microtubules, intermediate filaments, motor proteins, intracellular transport, cell shape, mechanical support, cilia, flagella, and cell movement.

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Cellular Energy & Metabolism

Study ATP coupling, redox chemistry, glycolysis, mitochondrial respiration, metabolic pathways, energy transfer, biosynthesis, and the relationship between cellular structure and metabolism.

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Protein Synthesis & Trafficking

Follow information and material from transcription and translation through folding, targeting, rough ER, vesicles, Golgi processing, secretion, membranes, and intracellular destinations.

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Cell Signaling

Study receptors, ligands, second messengers, phosphorylation, signal amplification, feedback, gene regulation, cell-cell communication, and how cells respond to changing environments.

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Cell Cycle & Division

Study cell-cycle control, DNA replication, checkpoints, mitosis, cytokinesis, chromosome segregation, growth, quiescence, senescence, and regulated cell death.

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Cell Junctions & Extracellular Matrix

Study cell adhesion, tight and gap junctions, anchoring structures, extracellular matrix, mechanotransduction, polarity, tissue organization, and communication between cells and their surroundings.

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Microscopy & Cell Methods

Study optical and electron microscopy, fluorescence, labeling, live-cell imaging, cell culture, fractionation, flow cytometry, image interpretation, controls, resolution, and experimental limitations.

Signature instrument · cell structure & exchange

Select a structure, then follow its dependencies outward.

The old page treated organelles as factory departments and displayed invented counts and performance metrics. The new lab focuses on actual structures, processes, and connections, and keeps scale limitations visible.

Explorable cell · schematic animal-cell view

How do cellular structures divide work and exchange material?

Select a structure to connect its local role to the rest of the cell. The drawing emphasizes relationships, not literal scale, abundance, shape, or position. Real cells vary strongly across cell type, organism, developmental state, activity, and experimental preparation.

Selected structureNucleus

Double-membrane compartment

Structure index
example biosynthetic traffic
generalized animal-cell schematic · not to scale click a structure
Local role

Contains most of the nuclear genome in eukaryotic cells and organizes processes including transcription, RNA processing, DNA replication, and chromosome segregation.

Processes
DNA storage & replicationtranscriptionRNA processingnuclear transport
Connections
nuclear envelope is continuous with endoplasmic reticulum
nuclear pores regulate traffic between nucleus and cytoplasm
gene expression supplies RNA used throughout the cell
Scale boundary

The diagram combines structures that operate across very different spatial scales. A ribosome, membrane bilayer, Golgi stack, mitochondrion, and nucleus cannot be drawn together at one truthful scale and remain readable.

Seeing cells · reference, not navigation

A cell diagram and a micrograph answer different questions.

01Diagram

A teaching diagram can place structures together clearly even when their real sizes, shapes, numbers, and positions vary.

02Light microscopy

Visible structures depend on optical resolution, contrast, staining or fluorescence, specimen preparation, and what labels are present.

03Electron microscopy

Higher spatial resolution can reveal membrane and ultrastructural detail, but preparation produces a particular view of fixed material rather than a live whole cell.

04Live-cell imaging

Time-dependent behavior can be observed, but labels, illumination, sampling rate, focal plane, and experimental conditions shape what becomes visible.

System principles

Structure only makes sense in process.

01Compartments create local conditionsMembranes can separate reactions, gradients, enzymes, substrates, and regulatory states while still allowing controlled exchange.
02Traffic links compartmentsVesicles, pores, transporters, diffusion, motor proteins, and membrane contact sites move information and material between cellular regions.
03Structure and process are inseparableA membrane, filament, pore, ribosome, enzyme complex, or organelle matters because its physical organization changes what reactions and movements are possible.
04Cells are variableOrganelle number, morphology, abundance, location, gene expression, metabolic state, and membrane organization differ across cell types and conditions.
05Models choose what to showNo single cell picture can truthfully display molecular scale, organelle architecture, dynamic trafficking, whole-cell geometry, and experimental evidence at once.
06Evidence has a methodClaims about cell structure come from microscopy, labeling, genetics, biochemical assays, perturbations, fractionation, sequencing, and many other methods with different limitations.