Succinate dehydrogenase (SDH) produces reduced flavin (FADH₂) as a product

This misconception is so widespread, even the exam boards get it wrong. Page 41 of the Edexcel GCE specification for A-level biology (2008 onwards) states that students should be able to…

Describe the role of the Krebs cycle in the complete oxidation of glucose and formation of carbon dioxide (CO₂), ATP, reduced NAD and reduced FAD (names of other compounds are not required) and that respiration is a many-stepped process with each step controlled and catalysed by a specific intracellular enzyme. [my emphasis]