Here’s the Q cycle, an important redox loop and function of complex III in mitochondria. The Q cycle is part of the mitochondrial electron transport chain and transports electrons from reduced ubiquinone QH2 to cytochrome c via a Rieske iron-sulphur protein. It’s also important in setting up a proton gradient across the inner membrane - while the Qo site aims to oxidise QH2 to Q, the Qi site actually reduces Q to QH2. Qo electrons alternate between reducing cyt c and Q (or ubisemiquinone QH·). Since the ubiquinone can accept up to two electrons, the steps 3 and 4 are essentially the same as steps 1 and 2. Directionality is governed by the redox potentials of the various carriers and probably by the fact that reduced Rieske Fe·S protein takes a different conformation to the oxidised form.


The Q Cycle by Ayraethazide is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

The psychedelic mandala you are gazing at is a convergent beam electron diffraction pattern.

Electron diffraction refers to the wave nature of electrons. However, from a technical or practical point of view, it may be regarded as a technique used to study matter by firing electrons at a sample and observing the resulting interference pattern. This phenomenon is commonly known as the wave-particle duality, which states that the behavior of a particle of matter (in this case the incident electron) can be described by a wave. For this reason, an electron can be regarded as a wave much like sound or water waves. This technique is similar to X-ray and neutron diffraction.

Electron diffraction is most frequently used in solid state physics and chemistry to study the crystal structure of solids.