Question

Which one is important in the electron transport system?
A) Ubiquinone
B) Acetyl CoA
C) Tricarboxylic acid
D) Ferricyanide

Answer 1

Hint: Electron Transport Chain can be defined as a series of compounds where a chemical gradient is developed by making use of electrons from the electron carrier. It is basically used to power the process of oxidative phosphorylation.

Complete answer:
Electron transport is a process that happens as a series of redox reactions. This is the only phase of glucose metabolism that makes use of atmospheric oxygen and it is a part of aerobic respiration. The electrons are passed from one component to another until the end of the chain where the electrons function and reduce molecular oxygen and produce water.

\[{\text{Q and Complex 2 - Succinate - Q reductase}}\]: \[{\text{FADH2}}\] that is not passed through \[{\text{complex 1}}\] is received directly from\[{\text{complex 2}}\]. Ubiquinone is the most important electron transport system because it functions in connecting the first and second complex to the third complex.

- Ubiquinone soluble in water and can move freely in the hydrophobic core of the membrane.
- Acetyl coenzyme A is a molecule involved in the Krebs cycle for energy production.
- The tricarboxylic acid cycle is also called the Krebs cycle and citric acid cycle. It is the second stage of cellular respiration.
- Ferricyanide is a redox dye with and it might function as an electron acceptor from respiratory chain intermediates.

Therefore, the correct answer is Option ‘A’.

Note: The three main steps in the electron transport chain are:
- A proton gradient is generated across the mitochondrial membrane and the accumulation of protons happens in the intermembrane space of mitochondria.
- Molecular oxygen is reduced and water is formed. The terminal electron acceptor is oxygen.
- ATP is synthesised by chemiosmosis and the enzyme involved in ATP synthesis is ATP synthase.