Question

Which compound of ETS is mobile ${ e }^{ - }$ carrier?
(A)UQ (CO-Q)
(B)Cytochrome a
(C)Cytochrome b
(D)Cytochrome f

Answer 1

Hint: Electron transport system (ETS) involves a certain mobile ${ e }^{ - }$ carrier which is a coenzyme that moves the electrons to Cytochrome b-${ c }_{ 1 }$ from complex I. This system involves the usage of Gibbs free energy and is an exergonic process.

Complete answer:
In the case of an electron transport system (ETS), the protein ubiquinone (UQ) acts as the mobile ${ e }^{ - }$ carrier and transports electrons from complex I to Cytochrome b-${ c }_{ 1 }$ complex. This UQ is functionally equivalent to the photoquinone of chloroplast electron transport protein.

Additional Information: Ubiquinone is also known as Coenzyme Q which is the most common form of Coenzyme Q10 or Ubiquinone-10 in humans. It is a coenzyme family that is ubiquitous in Animals and most bacteria. It is used as a dietary supplement and ingredient in some cosmetics.
Cytochrome is a redox-active protein containing a heme and a central Fe atom. The Fe atom represents the core whereas heme acts as a cofactor. These are involved in ETS and redox catalysis and are classified into four types based on the type of heme and its mode of binding. These are- Cytochrome a, Cytochrome b, Cytochrome c, and Cytochrome d.
Therefore, the correct answer is "UQ (CO-Q)".

Note: The Electron transport chain is a series of complexes that are involved in the transfer of electrons from the donors to the electron acceptors via redox reaction which involves the simultaneous process of reduction and oxidation. This system is made up of peptides, enzymes, and other molecules and uses Gibbs free energy to occur. The flow of electrons through this system is an ergonomic process. In complex I, of this system two electrons are removed from NADH to be transferred to UQ.