Archive | Notes

Photosynthesis in prokaryotic organisms occurs in la­mellar membrane systems called chromatophores. The chromatophores contain the pigments for the photochemical reactions but none of the subsequent biosynthetic enzymes. The pigment system includes the chlorophylls, carotenoids, and in some cases phycobilins. However, in the purple and green bacteria, bacteriochlorophyll is the ultimate light-trapping molecule (not chlorophyll a). Only the cyanobacteria have chlorophyll [...]

The tricarboxylic acid cycle is also called the Krebs cycle because the major steps of the cycle were worked out in 1937 by Sir Hans Krebs. At that time, radioactively labeled compounds were not available for biological studies and the cellular site of the reac­tions was not known with certainty. The experiments performed by Krebs and the logic and reasoning [...]

The NADH, H+, and FADH2 that accumulate as the TCA cycle operates form an enormous potential en­ergy pool. The reduced coenzymes are reoxidized and transfer their reducing capabilities through a se­quence of compounds to oxygen, which accepts elec­trons and H+ to form water. The sequence of carriers through which the electrons and H + pass is called the electron transport [...]