Question

Give an account of the synthesis of ATP in respiration.   ( can i please get some help with this question)

Answer 1

Answer

Cellular respiration is a metabolic pathway that breaks down glucose and produces ATP. The stages of cellular respiration include glycolysis, pyruvate oxidation, the citric acid or Krebs cycle, and oxidative phosphorylation.

1. Glycolysis. In glycolysis, glucose—a six-carbon sugar—undergoes a series of chemical transformations. In the end, it gets converted into two molecules of pyruvate, a three-carbon organic molecule. In these reactions, ATP is form and NAD+ Is converted into NADH

2. Pyruvate oxidation. Each pyruvate from glycolysis goes into the mitochondrial matrix—the innermost compartment of mitochondria. There, it’s converted into a two-carbon molecule bound to Coenzyme A, known as acetyl CoA. Carbon dioxide is released and NADH is generated.

3. Citric acid cycle. The acetyl CoA made in the last step combines with a four-carbon molecule and goes through a cycle of reactions, ultimately regenerating the four-carbon starting molecule. ATP, NADH and FADH2 are produced, and carbon dioxide is released.

4. Oxidative phosphorylation. The NADH and FADH2 form in previous steps transfer their electrons in the electron transport chain, turning back into NAD+ and FAD form. As electrons move down the chain, energy is released and used to pump protons out of the matrix, forming a gradient. Protons flow back into the matrix through an enzyme called ATP synthase, making ATP. At the end of the electron transport chain, oxygen accepts electrons and takes up protons to form water.

ATP SYNTHESIS

ATP synthase catalyzes the final step of oxidative or photophosphorylation, the synthesis of ATP from adenosine diphosphate (ADP) and Pi. Proton translocation, down the electrochemical gradient, through the membrane-embedded F0 subcomplex supplies the energy for ATP synthesis on the peripheral F1 subcomplex. F0 has the subunit composition ab2cn and F1 consists of subunits α3β3γδϵ. F1 contains six nucleotide-binding sites. Three of these sites, located on the three β-subunits at the interface to the adjacent α-subunit, participate in catalysis (“catalytic sites”). The remaining three sites, located mainly on the α-subunits, have no known physiological function (“noncatalytic sites”). F1 can be easily detached from the membrane and is an active ATPase (“F1-ATPase”). The holoenzyme is also referred to as “F1F0-ATP synthase” or F1F0. In this process, electrical energy is converted to chemical energy, and it is the supply of ADP that limits the rate of this process.