Figure 3.

ComplexII ambiguities. FADH₂ is depicted as (1) product and (2) substrate of Complex II by (A) (4), (B) (80), as in ref. (48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 104, 192, 193, 194, 199, 201, 202, 203, 204, 205, 206, 209, 210, 211, 213, 215, 216, 217, 218, 219, 220, 222, 225, 226, 227, 231, 233, 236, 239, 240, 241, 245, 271-280, 285, 291, 292, 293, 294, 295, 304, 305, 306, 308, 311, 312, 314, 320, 330). NADH and NAD⁺ cycle between different types of enzymes (yellow circle), in contrast to the FAD/FADH₂ cycle located within the same enzyme molecule (SDH and CII are synonyms). C, from ambiguous NADH-FADH₂ analogy (73) to (D) graphical misconception (58), as in ref. (100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240). NADH and FADH₂ at the doors of CI and CII, respectively, shown by (E) an international team (169) and (F) an international consortium suggesting guidelines (198); FADH₂ cannot enter – it functions always inside CII like FAD which receives electrons from the substrate succinate. G, the redox reaction of the flavin adenine dinucleotide is copied from the nicotinamide adenine dinucleotide with an unjustified indication of 2H⁺ formation in the mt-matrix, confusing in the context of the protonmotive force. The figure from ref. (264) is similar or identical to zooms into 33 figures from ref. (49, 57, 70, 72, 133, 154, 186, 244, 246, 249, 251, 252, 253, 254, 255, 257, 262, 263, 264, 267, 269, 270, 272, 273, 275, 276, 277, 278, 279, 280, 317, 319). H, the CII ambiguity in FADH₂→FAD+2H⁺ (242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280) fires back at the CI-catalyzed reaction when NAD⁺ is shown like FAD as NAD without charge (245, 271). I, the NADH→NAD⁺ analogy is taken to the level of copying a charge to FAD⁺ ((288), as in (281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319)) or (J) FADH⁺ ((331), as in (332)). K, exponential increase of publications with graphical Complex II ambiguities, 2001 to October 2023. Open symbol: the count of 46 publications in 2023 was adjusted for the full year by a multiplication factor of 12/10. Asterisc: zero count in 2004 set at 0.1 for exponential fit. N = 312 is the number of publications found with graphical CII ambiguities (Table 2).