What are Respiratory assemblies responsible for?

Cellular Respiration

Cellular respiration is the process that releases energy from glucose (C6H12O6) in the presence of oxygen (O2). The energy is captured in the form of ATP, which is used to power cellular processes. Cellular respiration occurs in the mitochondria of cells and can be broken down into three stages: glycolysis, the Krebs cycle, and the electron transport chain.

The Role of Respiratory Assemblies

The respiratory assemblies are involved in the electron transport chain, which is the final stage of cellular respiration. The electron transport chain is a series of protein complexes located in the inner mitochondrial membrane. These complexes use the energy from NADH and FADH2, two molecules that carry electrons, to pump protons (H+) across the inner mitochondrial membrane. This creates a proton gradient, which drives the synthesis of ATP by the ATP synthase complex.

The four respiratory assemblies are:

Complex I (NADH-CoQ oxidoreductase)

Complex I is the first complex in the electron transport chain and is responsible for transferring electrons from NADH to coenzyme Q (CoQ). This complex contains FMN (flavin mononucleotide) and several iron-sulfur clusters as electron carriers.

Complex II (succinate dehydrogenase)

Complex II is also involved in the electron transport chain and transfers electrons from succinate to CoQ. This complex is composed of several subunits, including the flavoprotein dehydrogenase and several iron-sulfur clusters.

Complex III (cytochrome bc1 complex)

Complex III is a multi-subunit complex that contains cytochromes b, c1, and c. This complex transfers electrons from CoQ to cytochrome c.

Complex IV (cytochrome c oxidase)

Complex IV is the final complex in the electron transport chain and transfers electrons from cytochrome c to oxygen (O2). This complex contains several cytochromes and copper atoms as electron carriers.