1.What is oxidative phosphorylation?
2.Define RQ.What is its value for fat?
3.Give difference between Glycolysis n fermentation.
4.Explain Electron Transport system .

Solution:

1. Oxidative phosphorylation is the enzymatic process in cell membrane that synthesis ATP from ADP and phosphate in the presence of ATP synthase enzyme in the matrix of mitochondria.

2. Respiratory quotient (RQ) or respiratory ratio can be defined as the ratio of the volume of CO ₂ evolved to the volume of O ₂ consumed during respiration. The value of respiratory quotient depends on the type of respiratory substrate. Its value is always less than one for fats as fats consume more oxygen for respiration than carbohydrates, for which its value is one.
 
3. Glycolysis is an enzymatic set of biochemical reactions in which glucose is changed to two molecules of pyruvate with the release of energy (ATP) and NADH.

Fermentation is a metabolic process by which glucose is converted into either alcohol or lactic acid in the absence of oxygen. It is also known as anaerobic respiration. Fermentation occurs in some bacteria, yeasts and in the muscles during heavy exercise. It results in no gain of energy as pyruvate is converted into a waste product.

4. Electron Transport Chain (ETS)

• NADH and FADH₂ are oxidised to release the energy stored in them.

• Electrons are passed from one carrier to another, and finally to oxygen, resulting in the formation 

• Electrons produced by NADH in the mitochondrial matrix are oxidised by Complex I (NADH dehydrogenase).

• Electrons are then transferred to ubiquinone, located in the inner mitochondrial membrane. Ubiquinone receives reducing equivalents through Complex II (FADH₂).

• Reduced ubiquinone (ubiquinol) is then oxidised by the transfer of electrons from Complex III (cytochrome bc ₁ complex) to cytochrome c.

• Cytochrome c transfers the electrons between Complex III and Complex IV (Cytochrome c − oxidase complex consists of cyt a and a ₃, along with two copper centres).

• In the course of passing from one carrier to another, electrons couple with Complex V (ATP synthase) and produce ATP.

• Oxidation of 1 NADH produces 3 ATPs.
  Oxidation of 1 FADH₂ produces 2 ATPs.

• Role of oxygen in the terminal stage of ETS: It acts as the final hydrogen acceptor; removes hydrogen from the process and drives the whole process.