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Photosynthesis

In brief

Photosynthesis couples energy capture with synthesis of organic compounds. In oxygenic photosynthesis, light-driven electron transfer uses water and releases oxygen; ATP and NADPH support carbon fixation. The carbon of new organic compounds comes from carbon dioxide. These are connected reactions rather than an instant conversion of light into a sugar molecule. [6] [7] [9] [10]

Evidence for this statement

Source-based explanation

Where to check this statement

biology59-photosynthesis
Electron Flow through Photosystems I and II; electron transport and ATP/NADPH paragraphs
biology59-carbon
Chloroplasts Capture Energy from Sunlight and Use It to Fix Carbon; carbon-fixation cycle paragraphs
biology59-light
How Light-Dependent Reactions Work; Figure8.17 explanatory text: PSII/PSI, ATP, NADPH and proton gradient; no figure reused
biology59-fixation
The Calvin Cycle; Stages1–3: fixation, reduction and regeneration; no quantitative ATP/NADPH lifetime or evolutionary dating claim used
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From sunlight to organic matter

A process definition is not an organism name. It connects articles about different organisms and structures while preserving their separate scientific identities.

[1] [2]
Evidence for this statement

Source-based explanation

Where to check this statement

go-photosynthesis
Captured GO ontology JSON: results[].id and definition.text
go-photosystem2
Captured GO ontology JSON: results[].id and definition.text

Photosystem II is one molecular participant in oxygenic photosynthesis. Its reaction centre uses light in electron transfer from water. A separate article connects this complex to an exact D1 protein record.

[1] [2]
Evidence for this statement

Source-based explanation

Where to check this statement

go-photosynthesis
Captured GO ontology JSON: results[].id and definition.text
go-photosystem2
Captured GO ontology JSON: results[].id and definition.text

Structure and function

Evidence for this statement

EcoGenesis

    Original teaching diagram of structures and roles described in this article. It is schematic: no specimen geometry, dimensions or measured activity are represented.
    1. Light and water

      Energy input and electron source

    2. Light reactions

      ATP and NADPH; oxygen released

    3. Carbon fixation

      CO₂ incorporated into organic molecules

    • Light and water → Light reactions: supports
    • Light reactions → Carbon fixation: ATP / NADPH

    Two connected photosystems

    In plant chloroplasts, photosystem II and photosystem I work in a connected electron-transfer pathway. Pigments absorb light and reaction centres initiate electron transfer. Water supplies replacement electrons at photosystem II. The pathway helps build a proton gradient and reduce NADP+ to NADPH. ATP synthase uses the gradient to make ATP.

    [6] [9]
    Evidence for this statement

    EcoGenesis

    Where to check this statement

    biology59-photosynthesis
    Electron Flow through Photosystems I and II; electron transport and ATP/NADPH paragraphs
    biology59-light
    How Light-Dependent Reactions Work; Figure8.17 explanatory text: PSII/PSI, ATP, NADPH and proton gradient; no figure reused

    Carbon fixation in the stroma

    The Calvin cycle uses ATP and NADPH to incorporate carbon dioxide into organic molecules, produce carbohydrate precursors and regenerate its carbon acceptor. Calling this stage light-independent describes the chemistry; it does not mean that the complete process is restricted to darkness.

    [7] [10]
    Evidence for this statement

    EcoGenesis

    Where to check this statement

    biology59-carbon
    Chloroplasts Capture Energy from Sunlight and Use It to Fix Carbon; carbon-fixation cycle paragraphs
    biology59-fixation
    The Calvin Cycle; Stages1–3: fixation, reduction and regeneration; no quantitative ATP/NADPH lifetime or evolutionary dating claim used

    Energy and matter

    The photosynthesis definition distinguishes the energy source from material used to synthesise organic compounds. Light supplies energy; carbon dioxide is named as a carbon source. Read an explanation by separately following energy input and material conversion. The process definition does not specify its rate.

    [1]
    Evidence for this statement

    Explanation of retained sources

    Where to check this statement

    go-photosynthesis
    Captured GO ontology JSON: results[].id and definition.text

    One molecular step

    Photosystem II uses light in electron transfer from water to plastoquinone. This describes one complex in oxygenic photosynthesis, not the entire carbon-fixation process. The GO definition separately notes other photosynthetic bacteria that use different compounds to re-reduce the reaction centre.

    [2]
    Evidence for this statement

    Explanation of retained sources

    Where to check this statement

    go-photosystem2
    Captured GO ontology JSON: results[].id and definition.text

    What a record establishes

    A GO term in a protein annotation must be read with its evidence code. In the retained D1 record, some functions are assigned through a HAMAP model. That supports an annotation of a particular object; it does not measure photosynthetic activity in the photographed plant or establish an experiment’s conditions.

    [5]
    Evidence for this statement

    Explanation of retained sources

    Where to check this statement

    uniprot-P83755
    Captured provider JSON; named selected record and native source versions

    Connected concepts

    Chloroplast

    A chloroplast is a chlorophyll-containing plastid. It contains thylakoids and stroma, with some thylakoids organised into stacks called grana.

    [3] [4] [5]
    Evidence for this statement

    Source-based explanation

    Where to check this statement

    go-chloroplast
    Captured GO ontology JSON: results[].id and definition.text
    uniprot-P83755
    Captured provider JSON; named selected record and native source versions
    Photosystem II

    Photosystem II is a molecular complex associated with pigments and electron carriers. In chloroplasts and cyanobacteria it uses light to transfer electrons from water to plastoquinone.

    [2] [5]
    Evidence for this statement

    Source-based explanation

    Where to check this statement

    go-photosystem2
    Captured GO ontology JSON: results[].id and definition.text
    uniprot-P83755
    Captured provider JSON; named selected record and native source versions

    Continue with an organism

    The photographs and molecular record come from separate source materials.

    Norway spruce →Arabidopsis thaliana →

    Your research question

    Save the article to return to your question and this source version.

    Plan a test

    This is your research plan. Completing these fields does not confirm a hypothesis.

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    Sources and versions

    Editorial draft · human review pending

    1. GO:0015979 · photosynthesis

      2026-09-09T01:17:01.233038+00:00 · CC-BY-4.0

      Provenance and original
      Original SHA-256
      8649763135938e40bdb112c62e870749510eea1b750ff5d230a3061be5a3e017
      Processing
      Unmodified provider response; article text is an attributed educational summary.
      Version details
      QuickGO response did not supply a native ontology release; retrieval time and exact response hash retained.

      View original JSON · Download original

    2. GO:0009523 · photosystem II

      2026-09-09T01:17:35.068503+00:00 · CC-BY-4.0

      Provenance and original
      Original SHA-256
      56537702684f4e6949eb9b16430a8830740bc9fd3369b21e7b5a9b711a341b4f
      Processing
      Unmodified provider response; article text is an attributed educational summary.
      Version details
      QuickGO response did not supply a native ontology release; retrieval time and exact response hash retained.

      View original JSON · Download original

    3. GO:0009507 · chloroplast

      2026-09-09T01:17:34.931415+00:00 · CC-BY-4.0

      Provenance and original
      Original SHA-256
      13082607c7dcc9e92cd281f1fc6a8fdf2878bceba74e9d7b6ad50d43b0ce33ba
      Processing
      Unmodified provider response; article text is an attributed educational summary.
      Version details
      QuickGO response did not supply a native ontology release; retrieval time and exact response hash retained.

      View original JSON · Download original

    4. Arabidopsis thaliana, first leaf of control seedling grown without added NaCl; Figure 3A

      Retrieval date unknown · CC BY 4.0

      Provenance and original
      Original SHA-256
      fe305c7d3a3327a06dda04c186989b5b8b6dec101bfe13aa851a3bc47dc07b14
      Processing
      Panel A extracted; original g/t annotations and 1 µm scale retained; encoded as WebP.
    5. UniProt P83755 · entry 161 / sequence 2

      2026-09-09T01:17:34.554931+00:00 · CC-BY-4.0

      Provenance and original
      Source version
      entry 161; sequence 2
      Original SHA-256
      f16a5f33fbf85a12aa5c91ab31f6092f0bbe3be874040c84c4954e87b20ae3a9
      Processing
      Unmodified provider response; article text is an attributed educational summary.
      Version details
      Provider entry/sequence versions retained.

      View original JSON · Download original

    6. Cooper (2000) · Photosynthesis

      2026-10-01 · Terms of use on source site

      Provenance and original
      Source version
      Selected web passages checked 2026-10-01; no immutable response edition asserted
      Source reading scope
      Named background passages only; not new experimental evidence.
      Location in the original source
      Electron Flow through Photosystems I and II; electron transport and ATP/NADPH paragraphs
    7. Alberts et al. (2002) · Chloroplasts and Photosynthesis

      2026-10-01 · Terms of use on source site

      Provenance and original
      Source version
      Selected web passages checked 2026-10-01; no immutable response edition asserted
      Source reading scope
      Named background passages only; not new experimental evidence.
      Location in the original source
      Chloroplasts Capture Energy from Sunlight and Use It to Fix Carbon; carbon-fixation cycle paragraphs
    8. Clark, Douglas & Choi · Biology 2e · 8.1 Overview of Photosynthesis

      2026-10-01 · Terms of use on source site

      Provenance and original
      Source version
      Selected publisher HTML passages checked 2026-10-01
      Source reading scope
      Named foundational biology paragraphs only; background facts checked against classical textbooks and captured GO/UniProt records; not an experimental result.
      Location in the original source
      Basic Photosynthetic Structures: envelope, thylakoid membranes, grana, lumen and stroma
    9. Clark, Douglas & Choi · Biology 2e · 8.2 Light-Dependent Reactions

      2026-10-01 · Terms of use on source site

      Provenance and original
      Source version
      Selected publisher HTML passages checked 2026-10-01
      Source reading scope
      Named foundational biology paragraphs only; background facts checked against classical textbooks and captured GO/UniProt records; not an experimental result.
      Location in the original source
      How Light-Dependent Reactions Work; Figure8.17 explanatory text: PSII/PSI, ATP, NADPH and proton gradient; no figure reused
    10. Clark, Douglas & Choi · Biology 2e · 8.3 Carbon Fixation

      2026-10-01 · Terms of use on source site

      Provenance and original
      Source version
      Selected publisher HTML passages checked 2026-10-01
      Source reading scope
      Named foundational biology paragraphs only; background facts checked against classical textbooks and captured GO/UniProt records; not an experimental result.
      Location in the original source
      The Calvin Cycle; Stages1–3: fixation, reduction and regeneration; no quantitative ATP/NADPH lifetime or evolutionary dating claim used
    Inspect structured data
    Content version
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    Source version
    knowledge-20260909.1
    Updated
    2026-10-01