Question

Which complex is formed by $ Cyt{\text{ }}a $ and $ Cyt{\text{ }}a3 $ ?

Answer 1

Hint : In order to this question, first we will mention the complex type which is formed by $ Cyt{\text{ }}a $ and $ Cyt{\text{ }}a3 $ and then we will go through the concept of that type of complex which is formed. We will also discuss the structure of the required complex.

Complete Step By Step Answer:
Complex IV or cytochrome c oxidase is formed by $ Cyt{\text{ }}a $ and $ Cyt{\text{ }}a3 $ . The electron transport system is aided by Complex IV (ETS).
Cytochrome c oxidase, often known as Complex IV, is a large transmembrane protein complex found in bacteria, archaea, and eukaryotes' mitochondria. It is the membrane-bound final enzyme in the respiratory electron transport chain of cells. It takes an electron from each of the four cytochrome c molecules and transfers it to one dioxygen molecule, transforming molecular oxygen into two water molecules.
It binds four protons from the inner aqueous phase to form two water molecules, then translocates four more protons across the membrane, raising the transmembrane difference in proton electrochemical potential, which the ATP synthase then uses to create ATP.
In mammals, the complex is a large integral membrane protein made up of a number of metal prosthetic sites and protein subunits. In mammals, eleven subunits are made in the nucleus, while three are made in the mitochondria. Two hemes, cytochrome a and cytochrome a3, and two copper centres, $ CuA{\text{ }}and{\text{ }}CuB $ , make up the complex.
In fact, the cytochrome a3 and CuB combine to produce a binuclear core where oxygen is reduced. Cytochrome c attaches at the CuA binuclear centre and transmits an electron to it before being oxidised back to cytochrome c containing $ F{e^{3 + }} $ , which is reduced by the previous component of the respiratory chain (cytochrome bc1 complex, complex III).

Note :
The $ {H^ + } $ ion gradient will not occur within the mitochondrial membrane if Complex IV is prevented from performing its functions. The manufacturing of ATP molecules will be halted as a result. ATP synthase is a protein that undergoes oxidative phosphorylation to produce ATP.