History and Function: The Respiratory and Photosynthetic Electron Transport Chains

Abstract

The patterns of historical discovery and subsequent progressive understanding of chlorophyll systems and of haem proteins are compared. The electron transport chains of chloroplasts and mitochondria are briefly described and the different experimental and conceptual styles involved in their analysis examined. A role for classical bacterial electron transport studies in integrating our general ideas about electron transport in biological membranes is proposed. Special features of cyanobacterial electron transport involving both light and respiration are discussed. The evolutionary relationships between cytochrome c oxidases in eukaryotes, eubacteria and cyanobacteria are outlined. A general summary scheme linking electron transport in photosynthetic and respiratory chains is put forward.