#electron transfer

SciTech Chronicles. . . . . . . . .September 27th, 2025

I need to understaaaaand but I feel so dumb rn

The electron transport chain of plants contains the same set of electron carriers found in the mitochondria of other organisms (Figure 12.8). (...) Two protons are pumped out of the matrix per electron pair (see Figure 12.8). (...) In addition to the set of protein complexes describes above, the plant electron transport chain contains components not found in mammalian mitochondria (see Figure 12.8). (...) The FOF1-ATP synthase (also called complex V) consists of two major components, FO and F1 (see Figure 12.8). (...) Electrons feed off the main electron transport chain into this alternative pathway at the level of the ubiquinone pool (see Figure 12.8). (...) By draining off electrons from the ubiquinone pool (see Figure 12.8), the alternative pathway prevents overreduction, thus limiting the production of ROS and minimizing the detrimental effects of stress on respiration.

Electrons are transferred through centers A and B to ferredoxin (Fd), a small, water-soluble iron-sulfur protein (see Figures 7.19 and 7.27).

The PSI reaction center complex is a large multi-subunit complex (Figure 7.27). (...) The PSI reaction center complex from pea contains four LHCI complexes in addition to the core structure similar to that found in cyanobacteria (see Figure 7.27). (...) Additional electron acceptors include a series of three membrane-associated iron-sulfur proteins, also known as Fe-S centers: FeSX, FeSA, and FeSB (see Figure 7.27).

These four integral membrane complexes are vectorially oriented in the thylakoid membrane to function as follows (Figure 7.20; also see Figure 7.16):

Cytochrome f then transfers an electron to the blue-colored copper protein plastocyanin (PC), which in turn reduces oxidized P700 of PSI.

PSI reduces NADP+ to NADPH in the stroma by the action of ferredoxin (Fd) and the flavoprotein ferredoxin-NADP+ reductase (FNR).