chloroplast thylakoid

GO:0009534 · Membrane organelle · Other · Proposed

Sac-like membranous structures in a chloroplast combined into stacks, or grana, and present singly in the stroma as stroma thylakoids or frets that interconnect grana. [GO:0009534]

Part of: chloroplast (GO:0009507)

Has part: chloroplast thylakoid membrane (GO:0009535); chloroplast thylakoid lumen (GO:0009543)

Xrefs: uniprot.location:SL-0056 — Chloroplast thylakoid

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
chloroplast thylakoid membrane	Lipid	part of	`GO:0009535`			ESSENTIAL	Pigmented lipid bilayer that bounds the chloroplast thylakoid lumen and houses the light-reaction machinery. `GO:0009535` GO:0009535 defines the chloroplast thylakoid membrane as the pigmented membrane of a chloroplast thylakoid. `uniprot.location:SL-0058` — Chloroplast thylakoid membrane UniProt SL-0058 describes the chloroplast thylakoid membrane as a thylakoid child compartment.

Taxonomic distribution

NCBITaxon:33090 Viridiplantae — COMMON: Photosynthetic green algae and land plants contain chloroplasts with internal thylakoids that support oxygenic photosynthesis. [DOI:10.1098/rstb.2009.0103]
NCBITaxon:3055 Chlamydomonas reinhardtii — COMMON: The Chlamydomonas chloroplast contains a native thylakoid network with stacked and unstacked membrane regions. [DOI:10.7554/eLife.04889]

Canonical examples

NCBITaxon:3055 Chlamydomonas reinhardtii — Unicellular green alga whose native chloroplast thylakoids were resolved by cryo-focused ion beam milling and in situ cryo-electron tomography. [DOI:10.7554/eLife.04889]

Functions

photosynthetic electron transport chain GO:0009767 — Chloroplast thylakoid membranes house the light-reaction complexes that drive electron transport and build a trans-thylakoid proton gradient.
- GO:0009767 GO:0009767 defines the photosynthetic electron transport chain.
- DOI:10.1007/s00294-011-0339-1 Terashima, Specht and Hippler 2011 review Chlamydomonas chloroplast thylakoid photosynthetic complexes.

Mechanism graphs

Chloroplast thylakoid topology (FUNCTION)

The chloroplast thylakoid is an internal chloroplast compartment embedded in the stroma and bounded by a pigmented membrane that encloses the thylakoid lumen.

Subject	Predicate	Object	Evidence
chloroplast thylakoid	is embedded in	chloroplast stroma	`GO:0009507` GO:0009507 defines chloroplasts as chlorophyll-containing plastids with thylakoids embedded in a stroma.
chloroplast thylakoid membrane	encloses	chloroplast thylakoid lumen	`GO:0009543` GO:0009543 identifies the chloroplast thylakoid lumen enclosed by thylakoid membranes. `uniprot.location:SL-0057` — Chloroplast thylakoid lumen UniProt SL-0057 identifies the chloroplast thylakoid lumen as a child compartment of the chloroplast thylakoid.
chloroplast thylakoid	supports	photosynthetic electron transport chain	`uniprot.location:SL-0056` — Chloroplast thylakoid UniProt SL-0056 describes chloroplast thylakoids as carrying out the light reactions of photosynthesis.

Discussions

INTERPRETATION (RESOLVED): Keep the chloroplast thylakoid distinct from its bounding membrane and its lumen. GO:0009534 denotes the whole chloroplast thylakoid, while GO:0009535 denotes the pigmented bounding membrane and GO:0009543 denotes the chloroplast thylakoid lumen.
INTERPRETATION (RESOLVED): Represent chloroplast thylakoid as a membranous chloroplast substructure without asserting that it is an organelle. GO:0009579 describes thylakoids as membranous cellular structures and explicitly comments that they are not considered organelles; StructureKindEnum has no non-organelle membrane-bounded-compartment value.

Evidence

GO:0009534 Gene Ontology cellular-component term for chloroplast thylakoid.
GO:0009579 Gene Ontology cellular-component term for the broader thylakoid class.
GO:0031976 Gene Ontology cellular-component term for plastid thylakoid, the plastid-specific thylakoid parent.
GO:0009507 Gene Ontology cellular-component term for chloroplast.
GO:0009570 Gene Ontology cellular-component term for chloroplast stroma, the matrix compartment surrounding chloroplast thylakoids.
GO:0009535 Gene Ontology cellular-component term for the chloroplast thylakoid membrane.
GO:0009543 Gene Ontology cellular-component term for the chloroplast thylakoid lumen.
GO:0009767 Gene Ontology biological-process term for photosynthetic electron transport chain.
uniprot.location:SL-0056 — Chloroplast thylakoid UniProt Subcellular Location SL-0056 maps Chloroplast thylakoid to GO:0009534 and places it under the chloroplast location.
uniprot.location:SL-0057 — Chloroplast thylakoid lumen UniProt Subcellular Location SL-0057 maps Chloroplast thylakoid lumen to GO:0009543 and places it under chloroplast thylakoid.
uniprot.location:SL-0058 — Chloroplast thylakoid membrane UniProt Subcellular Location SL-0058 maps Chloroplast thylakoid membrane to GO:0009535 and places it under chloroplast thylakoid.
DOI:10.1098/rstb.2009.0103 Keeling 2010, The endosymbiotic origin, diversification and fate of plastids, Philosophical Transactions of the Royal Society B.
DOI:10.1007/s00294-011-0339-1 Terashima, Specht and Hippler 2011, The chloroplast proteome: a survey from the Chlamydomonas reinhardtii perspective with a focus on distinctive features, Current Genetics.
DOI:10.7554/eLife.04889 Engel et al. 2015, Native architecture of the Chlamydomonas chloroplast revealed by in situ cryo-electron tomography, eLife.

Curation history

2026-09-13T01:44:53Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-13T01:45:30Z codex · EXPANDED_RECORD — Added plastid-thylakoid parentage, chloroplast parthood, chloroplast thylakoid membrane and lumen parts, the UniProt SL-0056 xref, Chlamydomonas and Viridiplantae scope, photosynthesis evidence, a nonmechanistic thylakoid-topology graph, and resolved membrane/lumen and non-organelle boundary interpretations.
2026-09-13T01:46:03Z codex · NARROWED_FUNCTION — Narrowed the thylakoid function and topology node from broad photosynthesis to photosynthetic electron transport chain.
2026-09-13T01:53:57Z codex · ADDRESS_REVIEW — Resolved #734 by adding GO:0031976 plastid thylakoid parentage; resolved #735 by adding direct SL-0057/SL-0058 evidence for the lumen and membrane; resolved #736 by removing the imprecise membrane-bounds-whole-thylakoid topology edge.

Source: data/structures/membrane_organelle/chloroplast_thylakoid.yaml