Here is a dense set of (subject, predicate, object) triples about photosynthesis. I’ll group them roughly by topic, but every line is a single triple.

**Core definition and purpose**

1. (Photosynthesis, is, a biochemical process that converts light energy into chemical energy)  
2. (Photosynthesis, primarily occurs in, plants)  
3. (Photosynthesis, also occurs in, algae)  
4. (Photosynthesis, also occurs in, cyanobacteria)  
5. (Photosynthesis, occurs in, some other photosynthetic bacteria)  
6. (Photosynthesis, uses, light energy)  
7. (Photosynthesis, uses, water)  
8. (Photosynthesis, uses, carbon dioxide)  
9. (Photosynthesis, produces, carbohydrates)  
10. (Photosynthesis, produces, oxygen as a byproduct in oxygenic organisms)  
11. (Photosynthesis, is, endergonic)  
12. (Photosynthesis, stores, energy in chemical bonds)  
13. (Photosynthesis, is, the primary source of organic matter in most ecosystems)  
14. (Photosynthesis, is, the primary source of atmospheric oxygen)  
15. (Photosynthesis, underpins, most food chains on Earth)  
16. (Photosynthesis, drives, global biogeochemical cycles)  

**Overall reactions**

17. (Oxygenic photosynthesis, overall reaction, 6 CO₂ + 6 H₂O + light → C₆H₁₂O₆ + 6 O₂)  
18. (Oxygenic photosynthesis, produces, molecular oxygen from water)  
19. (Anoxygenic photosynthesis, does not produce, oxygen)  
20. (Anoxygenic photosynthesis, uses, electron donors other than water)  
21. (Anoxygenic photosynthesis, may use, H₂S as an electron donor)  
22. (Anoxygenic photosynthesis, may use, H₂ as an electron donor)  
23. (Anoxygenic photosynthesis, may use, Fe²⁺ as an electron donor)  
24. (General photosynthesis, transforms, inorganic carbon into organic carbon)  

**Location in eukaryotes (plants and algae)**

25. (In plants, photosynthesis, occurs in chloroplasts)  
26. (Chloroplasts, are, membrane-bound organelles)  
27. (Chloroplasts, contain, thylakoid membranes)  
28. (Chloroplasts, contain, stroma)  
29. (Thylakoid membranes, house, photosynthetic electron transport chain)  
30. (Thylakoid membranes, contain, photosystem II)  
31. (Thylakoid membranes, contain, photosystem I)  
32. (Thylakoid membranes, contain, cytochrome b₆f complex)  
33. (Thylakoid membranes, contain, ATP synthase complexes)  
34. (Stroma, contains, enzymes of the Calvin–Benson cycle)  
35. (Thylakoid lumen, accumulates, protons during light reactions)  

**Location in prokaryotes**

36. (In cyanobacteria, photosynthesis, occurs in thylakoid-like internal membranes)  
37. (In cyanobacteria, photosystems, are embedded in internal membranes)  
38. (In purple bacteria, photosynthesis, occurs in intracytoplasmic membrane vesicles)  
39. (In green sulfur bacteria, photosynthesis, occurs in specialized chlorosomes and membranes)  
40. (Prokaryotic photosynthesis, lacks, chloroplast organelles)  

**Two main stages**

41. (Photosynthesis, consists of, light-dependent reactions)  
42. (Photosynthesis, consists of, light-independent reactions)  
43. (Light-independent reactions, include, Calvin–Benson cycle in oxygenic phototrophs)  
44. (Light reactions, occur in, thylakoid membranes)  
45. (Calvin–Benson cycle, occurs in, chloroplast stroma in plants)  

**Light-dependent reactions (oxygenic)**

46. (Light-dependent reactions, require, light)  
47. (Light-dependent reactions, use, photosystems)  
48. (Light-dependent reactions, produce, ATP)  
49. (Light-dependent reactions, produce, NADPH)  
50. (Light-dependent reactions, produce, O₂ from water)  
51. (Photosystem II, absorbs, light energy around 680 nm)  
52. (Photosystem I, absorbs, light energy around 700 nm)  
53. (Photosystem II, oxidizes, water)  
54. (Water oxidation in PSII, releases, electrons)  
55. (Water oxidation in PSII, releases, protons into thylakoid lumen)  
56. (Water oxidation in PSII, releases, molecular oxygen)  
57. (Electrons from water, are transferred through, PSII → plastoquinone → cytochrome b₆f → plastocyanin → PSI)  
58. (Cytochrome b₆f complex, pumps, protons into thylakoid lumen)  
59. (Light absorption by PSI, excites, electrons to higher energy state)  
60. (Excited electrons from PSI, reduce, ferredoxin)  
61. (Ferredoxin, transfers electrons to, ferredoxin–NADP⁺ reductase)  
62. (Ferredoxin–NADP⁺ reductase, reduces, NADP⁺ to NADPH)  
63. (Proton gradient across thylakoid membrane, drives, ATP synthase)  
64. (ATP synthase, synthesizes, ATP from ADP and Pi)  
65. (Noncyclic electron flow, uses, both PSII and PSI)  
66. (Noncyclic electron flow, results in, NADPH and ATP and O₂ production)  
67. (Cyclic electron flow around PSI, recycles, electrons from ferredoxin to cytochrome b₆f)  
68. (Cyclic electron flow, increases, ATP production relative to NADPH)  
69. (Cyclic electron flow, does not produce, NADPH)  
70. (Cyclic electron flow, does not produce, O₂)  

**Pigments and light capture**

71. (Photosynthetic organisms, use, pigments to absorb light)  
72. (Chlorophyll a, is, the primary photosynthetic pigment in oxygenic organisms)  
73. (Chlorophyll a, absorbs, blue and red light most strongly)  
74. (Chlorophyll b, acts as, accessory pigment in plants and green algae)  
75. (Chlorophyll b, broadens, spectrum of absorbed light)  
76. (Carotenoids, are, accessory pigments)  
77. (Carotenoids, absorb, blue and blue-green light)  
78. (Carotenoids, protect, photosystems from photooxidative damage)  
79. (Phycobilins, are, accessory pigments in cyanobacteria and red algae)  
80. (Pigments, are organized into, light-harvesting complexes)  
81. (Light-harvesting complexes, funnel, excitation energy to reaction centers)  
82. (Reaction center chlorophyll, performs, primary charge separation)  
83. (Primary charge separation, initiates, electron transport chain)  

**Calvin–Benson cycle (C3 cycle)**

84. (Calvin–Benson cycle, is, the main carbon fixation pathway in most plants)  
85. (Calvin–Benson cycle, uses, ATP from light reactions)  
86. (Calvin–Benson cycle, uses, NADPH from light reactions)  
87. (Calvin–Benson cycle, fixes, CO₂ into organic molecules)  
88. (Calvin–Benson cycle, occurs in, three phases: carboxylation, reduction, regeneration)  
89. (Ribulose-1,5-bisphosphate (RuBP), is, the CO₂-acceptor molecule in C3 cycle)  
90. (Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), catalyzes, CO₂ fixation to RuBP)  
91. (RuBisCO, is, the most abundant enzyme on Earth by mass)  
92. (Carboxylation of RuBP, forms, two molecules of 3-phosphoglycerate (3-PGA))  
93. (3-phosphoglycerate, is reduced to, glyceraldehyde-3-phosphate (G3P) using ATP and NADPH)  
94. (Glyceraldehyde-3-phosphate, can be converted to, hexose phosphates)  
95. (Hexose phosphates, are used to synthesize, sucrose and starch)  
96. (Part of G3P, is used to regenerate, RuBP)  
97. (RuBP regeneration, requires, ATP)  

**Photorespiration and RuBisCO oxygenase activity**

98. (RuBisCO, also catalyzes, oxygenation of RuBP)  
99. (Oxygenation of RuBP, produces, one 3-PGA and one 2-phosphoglycolate)  
100. (2-phosphoglycolate, enters, photorespiratory pathway)  
101. (Photorespiration, consumes, O₂)  
102. (Photorespiration, releases, CO₂)  
103. (Photorespiration, consumes, ATP and reducing power)  
104. (Photorespiration, reduces, net photosynthetic efficiency)  
105. (High O₂/CO₂ ratio at RuBisCO, increases, photorespiration rate)  
106. (High temperature, increases, RuBisCO oxygenase activity relative to carboxylase activity)  

**C4 photosynthesis**

107. (C4 photosynthesis, is, a carbon-concentrating mechanism)  
108. (C4 plants, initially fix, CO₂ into a four-carbon compound)  
109. (C4 initial fixation, uses, phosphoenolpyruvate carboxylase (PEPC))  
110. (PEPC, catalyzes, fixation of bicarbonate (HCO₃⁻) to phosphoenolpyruvate)  
111. (PEPC, is not inhibited by, O₂)  
112. (Mesophyll cells in C4 plants, fix, CO₂ into oxaloacetate)  
113. (Oxaloacetate, is converted to, malate or aspartate)  
114. (Malate or aspartate, is transported to, bundle sheath cells)  
115. (Bundle sheath cells, decarboxylate, C4 acids to release CO₂)  
116. (Released CO₂, is fixed by, RuBisCO in bundle sheath chloroplasts)  
117. (C4 photosynthesis, concentrates, CO₂ around RuBisCO)  
118. (C4 photosynthesis, reduces, photorespiration)  
119. (C4 pathway, requires, additional ATP compared to C3)  
120. (C4 photosynthesis, is advantageous in, high light and high temperature environments)  
121. (C4 plants, include, maize)  
122. (C4 plants, include, sugarcane)  
123. (C4 plants, include, sorghum)  

**CAM photosynthesis**

124. (Crassulacean Acid Metabolism (CAM), is, a temporal carbon-concentrating mechanism)  
125. (CAM plants, open, stomata at night)  
126. (Nighttime CAM fixation, uses, PEPC to fix CO₂ into organic acids)  
127. (Organic acids in CAM, are stored in, vacuoles as malate or malic acid)  
128. (CAM plants, close, stomata during the day)  
129. (During day, CAM plants, decarboxylate stored acids to release CO₂)  
130. (Released daytime CO₂ in CAM, is fixed by, RuBisCO via Calvin–Benson cycle)  
131. (CAM photosynthesis, conserves, water)  
132. (CAM photosynthesis, is adaptive in, arid environments)  
133. (CAM plants, include, many succulents)  
134. (CAM plants, include, cacti)  
135. (Some species, can, shift between C3 and CAM (facultative CAM))  

**Anoxygenic photosynthesis and bacterial diversity**

136. (Anoxygenic photosynthetic bacteria, use, single photosystem)  
137. (Purple bacteria, use, type II reaction center)  
138. (Green sulfur bacteria, use, type I reaction center)  
139. (Bacterial photosystems, are, evolutionarily related to PSI and PSII)  
140. (Anoxygenic phototrophs, generate, proton motive force via electron transport)  
141. (Anoxygenic phototrophs, often use, cyclic electron flow only)  
142. (Anoxygenic phototrophs, reduce, NAD(P)⁺ via reverse electron transport or special carriers)  
143. (Green sulfur bacteria, use, sulfur compounds as electron donors)  
144. (Purple sulfur bacteria, store, sulfur granules)  
145. (Heliobacteria, perform, anoxygenic photosynthesis in Gram-positive bacteria)  

**Energy and thermodynamics**

146. (Photosynthesis, converts, low-energy oxidized compounds into high-energy reduced compounds)  
147. (Photosynthesis, decreases, entropy locally while increasing entropy globally)  
148. (Photosynthesis, is driven by, photon absorption)  
149. (Photon absorption by pigments, causes, electronic excitation)  
150. (Excited-state energy, is transferred by, resonance energy transfer)  
151. (Excess excitation energy, can be dissipated as, heat)  
152. (Excess excitation energy, can be emitted as, fluorescence)  
153. (Non-photochemical quenching, dissipates, excess light energy as heat)  

**Regulation and environmental responses**

154. (Photosynthesis rate, depends on, light intensity)  
155. (Photosynthesis rate, depends on, CO₂ concentration)  
156. (Photosynthesis rate, depends on, temperature)  
157. (Photosynthesis rate, depends on, water availability)  
158. (At low light, photosynthesis, is limited by light)  
159. (At high light, photosynthesis, can be limited by, CO₂ or biochemical capacity)  
160. (Very high light, can cause, photoinhibition)  
161. (Photoinhibition, involves, damage to PSII reaction center)  
162. (Plants, repair, photodamaged PSII via D1 protein turnover)  
163. (Stomata, regulate, CO₂ uptake)  
164. (Stomata, also regulate, transpirational water loss)  
165. (Water stress, causes, stomatal closure)  
166. (Stomatal closure, reduces, CO₂ uptake)  
167. (Low CO₂ in leaf, increases, photorespiration)  
168. (Nitrogen status of plant, affects, photosynthetic capacity via protein content)  
169. (Iron availability, affects, photosynthetic electron transport components)  

**Structural and anatomical features**

170. (Leaves, are specialized for, photosynthesis in most plants)  
171. (Leaf mesophyll, contains, high density of chloroplasts)  
172. (Palisade mesophyll, is, main site of light absorption)  
173. (Spongy mesophyll, facilitates, gas diffusion)  
174. (Epidermis, is covered by, cuticle)  
175. (Cuticle, reduces, water loss)  
176. (Stomata, are located in, leaf epidermis)  
177. (Guard cells, control, stomatal aperture)  
178. (C4 plants, exhibit, Kranz anatomy)  
179. (Kranz anatomy, features, concentric arrangement of mesophyll and bundle sheath cells)  
180. (Bundle sheath chloroplasts in C4, are often, agranal or with reduced grana)  

**Biochemical integration**

181. (Photosynthesis, provides, triose phosphates for sucrose synthesis in cytosol)  
182. (Photosynthesis, supplies, carbon skeletons for amino acid synthesis)  
183. (Photosynthesis, supplies, carbon for fatty acid synthesis)  
184. (Triose phosphate/phosphate translocator, exchanges, triose phosphates for inorganic phosphate between stroma and cytosol)  
185. (Starch, is synthesized in, chloroplast stroma)  
186. (Sucrose, is synthesized in, cytosol)  
187. (Daytime, favors, starch accumulation in chloroplasts)  
188. (Nighttime, favors, starch degradation and export of sugars)  

**Evolutionary aspects**

189. (Oxygenic photosynthesis, evolved, in cyanobacteria)  
190. (Cyanobacterial photosynthesis, led to, Great Oxidation Event)  
191. (Great Oxidation Event, increased, atmospheric O₂ dramatically)  
192. (Endosymbiosis of cyanobacteria, gave rise to, chloroplasts in eukaryotes)  
193. (Chloroplasts, retain, their own genome)  
194. (Chloroplast genome, encodes, some photosynthetic proteins)  
195. (Most chloroplast proteins, are encoded by, nuclear genome)  
196. (Chloroplast origin, is supported by, similarity to cyanobacteria in structure and DNA)  
197. (Different photosynthetic pathways (C3, C4, CAM), evolved, multiple times independently)  

**Ecological and global significance**

198. (Photosynthesis, fixes, ~100–130 gigatons of carbon per year globally)  
199. (Marine phytoplankton, contribute, roughly half of global primary productivity)  
200. (Terrestrial plants, contribute, the other half of global primary productivity)  
201. (Photosynthesis, influences, atmospheric CO₂ levels)  
202. (Photosynthesis, moderates, Earth’s climate over geological timescales)  
203. (Photosynthetic organisms, form, base of most ecosystems’ food webs)  
204. (Deforestation, reduces, global photosynthetic capacity)  
205. (Ocean stratification, can reduce, nutrient supply to surface phytoplankton and thus photosynthesis)  

**Measurement and quantification**

206. (Photosynthetic rate, can be measured by, CO₂ uptake)  
207. (Photosynthetic rate, can be measured by, O₂ evolution)  
208. (Chlorophyll fluorescence, is used to assess, photosystem II efficiency)  
209. (Fv/Fm ratio, estimates, maximum quantum efficiency of PSII)  
210. (Gas exchange analysis,
