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oxygenic photosynthesis

traitmech:000034 · CLASS · REVIEWED

A phototrophic metabolism that uses light energy to fix CO2, oxidizing water as the electron donor and releasing molecular oxygen. It uses two linked photosystems and chlorophyll, and is characteristic of cyanobacteria (and plant chloroplasts).

Oxygenic photosynthesis splits water and releases O2

Evidence-backed causal sketch linking two linked photosystems and water oxidation to CO2 fixation and oxygen evolution.

Oxygenic photosynthesis splits water and releases O2 Interactive directed graph showing evidence-backed causal relationships for oxygenic photosynthesis.

Edge evidence

  • water oxidized to molecular oxygen METPO:2007405

    Water is the electron donor; its oxidation releases O2.

    • DOI:10.1016/j.tim.2006.09.001 Bryant & Frigaard contrast oxygenic photosynthesis (water-splitting, O2-evolving) with anoxygenic phototrophy.
  • photosynthetic electron transport enables oxygenic photosynthesis RO:0002327

    Two linked photosystems power electron flow from water to NADP+.

    • DOI:10.1146/annurev-earth-060313-054810 Fischer et al. support water-oxidizing, O2-evolving photosynthesis as a cyanobacterial innovation.
  • photosystem II oxidizes water METPO:2000016

    PSII is the primary catalyst of water oxidation in oxygenic photosynthesis.

    • DOI:10.1007/s11120-022-00991-y Shevela et al. 2023: PSII is the primary catalyst of water oxidation in oxygenic photosynthesis.
  • photosystem II reduces plastoquinone/plastoquinol pool METPO:2000017

    Electrons extracted from water reduce plastoquinone (PQ -> PQH2).

    • DOI:10.1007/s11120-022-00991-y Shevela et al. 2023: water oxidation extracts electrons that reduce plastoquinone (PQ -> PQH2).
  • plastoquinone/plastoquinol pool donates electrons to cytochrome b6f complex METPO:2007403

    Plastoquinol diffuses to reduce the cytochrome b6f complex.

    • DOI:10.3390/plants13152103 Milrad et al. 2024: PQH2 diffuses to reduce the cytochrome b6f complex.
  • cytochrome b6f complex transfers electrons to photosystem I METPO:2007403

    Cyt b6f transfers electrons to PSI via soluble carriers (plastocyanin or cytochrome c6).

    • DOI:10.3390/plants13152103 Milrad et al. 2024: electrons transferred from Cytb6f to PSI via plastocyanin or cytochrome c6.
  • photosystem I reduces ferredoxin METPO:2000017

    PSI oxidizes plastocyanin and reduces ferredoxin.

    • DOI:10.1111/1751-7915.14519 Grettenberger et al. 2024: PSI oxidizes plastocyanin and reduces ferredoxin.
  • ferredoxin-NADP+ reductase reduces NADPH METPO:2000017

    Ferredoxin-NADP+ reductase reduces NADP+ to NADPH using ferredoxin electrons.

    • DOI:10.1111/1751-7915.14519 Grettenberger et al. 2024: electrons via ferredoxin and FNR reduce NADP+ to NADPH.
  • photosynthetic electron transport generates proton motive force biolink:produces

    Linear electron transport generates the transthylakoid proton motive force.

    • DOI:10.3390/plants13152103 Milrad et al. 2024: membrane proton motive force produced by these transfers comprises dpH and dPsi.
  • proton motive force drives ATP

    The proton motive force drives ATP synthesis by ATP synthase.

    • DOI:10.1007/s11120-022-00991-y Shevela et al. 2023: raised proton motive force drives ATP synthesis by ATP synthase.

Provenance

Source
METPO (2025-11-25)
Definition source
DOI:10.1016/j.tim.2006.09.001

Parent traits (1)

kg-microbe context

Matched 1 kg-microbe node via parent_proxy.

  • METPO:1000060 [-1.052, -1.766, -1.194, +0.291, …]

512-dim DeepWalkSkipGramEnsmallen embedding from kg-microbe (2026-04-25).

Nearest neighbors in embedding space

Top-8 cosine-similar METPO traits from the 2026-04-25 deepwalk (512-D).

Curation history

  1. · PROPOSED_FROM_RESEARCH · claude

    Proposed candidate METABOLISM trait (oxygenic photosynthesis) from literature research to fill the phototrophy gap.

  2. · CURATED_CAUSAL_GRAPH · claude

    Added evidence-backed causal graph (water-splitting / O2 evolution) with CHEBI/GO node groundings and RO/METPO predicate groundings; promoted PROPOSED to REVIEWED.

  3. · ENRICH_CAUSAL_GRAPH · claude

    Added 8 evidence-backed generic edges (9 new nodes) from the deep-research report.

  4. · GROUND_CAUSAL_PREDICATES · claude

    Grounded 7 causal-edge predicate_id field(s) via mappings/predicate_grounding.tsv (METPO:2000017×3, METPO:2007403×2, METPO:2000016×1, biolink:produces×1).

  5. · GROUND_CAUSAL_NODES · claude

    Grounded 1 causal-node grounding field(s) via mappings/node_grounding.tsv (CHEBI:16474×1).

  6. · GROUND_CAUSAL_NODES · claude

    Grounded 2 causal-node grounding field(s) via mappings/node_grounding.tsv (UniProtKB:A0A009PCQ5×1, UniProtKB:A0A0E2H5I8×1).