During oxidation of one mole of glucose. 36ATP can be obtained by which of the following distribution?
During oxidation of one mole of glucose. 36ATP can be obtained by which of the following distribution?
The correct option is B Glycolysis-2, Citric acid cycle-2, ETS-32
GLYCOLYSIS
Glycolysis is the process that breaks down the 6-carbon glucose into 3-carbon pyruvate, which is a substrate for the link reaction. By using substrate-level phosphorylation, it adds a phosphate on either side of the 6-carbon glucose to make the molecule unstable, which breaks it down into the 3-carbon pyruvate. This process uses 2ATP, however, glycolysis itself produces 4ATP, making it a net gain of 2ATP.
ATP Count: 2ATP
KREBS CYCLE
Remember the pyruvate that was made in glycolysis? It underwent a link reaction which converted it into acetyl coenzyme A, or simply acetyl-CoA, which is now a 2-carbon structure and also the substrate for the Krebs Cycle.
Acetyl-CoA binds to the 4-carbon molecule that is made in the final stage of Krebs Cycle, creating a 6-carbon molecule known as Citrate. It undergoes decarboxylation twice, which removes a carbon one at a time, and also synthesizes NAD+ into NADH. These are the energy carriers that aid the ETC to synthesize ADP + Pi into ATP. More on that later.
Now that the 6-carbon molecule has been decarboxylated into a 4-carbon molecule and NAD+ has been synthesized into NADH, the 4-carbon molecule undergoes redox reactions, and right before the cycle repeats itself, an ADP molecule and a Pi molecule come together and fuse, creating an ATP molecule.
The Krebs Cycle occurs twice for each glucose molecule, so the net gain here is +2 ATP.
ATP Count: 4ATP (2 from glycolysis, two from Krebs Cycle)
ELECTRON TRANSPORT CHAIN
Remember those NADH that the Krebs Cycle made from NAD+? These are electron carriers that drop off their H+ protons to the enzymes in the mitochondrial membrane. The enzymes are arranged in increasing electronegativity, so when the electron is dropped off by the NADH at the first enzyme, it passes through molecules that are more electronegative than the electron itself. This creates a proton gradient, as this passage of the electron allows for free-roaming H+ protons inside the mitochondrial matrix to make their way into the intermembrane space and create a gradient for ATP synthesis to occur.
After the electron makes its way through the electronegative enzymes, it arrives at the final enzyme, where an O2 molecule awaits. The final enzyme fuses the O2 molecule and final electron together, creating H20. Thus, we can say that O2 is the final electron acceptor in the electron transport chain.
Now that we’ve dealt with the electron, let’s see what happens to the gradient it created. The H+ protons in the mitochondrial matrix now make their way to the nearest ATP Synthase molecule, which is the place where ADP + Pi come together to fuse into ATP. The protons enter the ATP Synthase enter through its opening on the side of the intermembrane space. Once inside, the synthase uses the energy in the proton to fuse the ADP + Pi that are waiting in its active site on the matrix side through substrate-level phosphorylation.
This is the final part of cellular respiration, and has the highest ATP yeild of all.
ATP Count: 36 ATP (2 from glycolysis, two from Krebs Cycle, 32 from ETC)
GLYCOLYSIS
Glycolysis is the process that breaks down the 6-carbon glucose into 3-carbon pyruvate, which is a substrate for the link reaction. By using substrate-level phosphorylation, it adds a phosphate on either side of the 6-carbon glucose to make the molecule unstable, which breaks it down into the 3-carbon pyruvate. This process uses 2ATP, however, glycolysis itself produces 4ATP, making it a net gain of 2ATP.
ATP Count: 2ATP
KREBS CYCLE
Remember the pyruvate that was made in glycolysis? It underwent a link reaction which converted it into acetyl coenzyme A, or simply acetyl-CoA, which is now a 2-carbon structure and also the substrate for the Krebs Cycle.
Acetyl-CoA binds to the 4-carbon molecule that is made in the final stage of Krebs Cycle, creating a 6-carbon molecule known as Citrate. It undergoes decarboxylation twice, which removes a carbon one at a time, and also synthesizes NAD+ into NADH. These are the energy carriers that aid the ETC to synthesize ADP + Pi into ATP. More on that later.
Now that the 6-carbon molecule has been decarboxylated into a 4-carbon molecule and NAD+ has been synthesized into NADH, the 4-carbon molecule undergoes redox reactions, and right before the cycle repeats itself, an ADP molecule and a Pi molecule come together and fuse, creating an ATP molecule.
The Krebs Cycle occurs twice for each glucose molecule, so the net gain here is +2 ATP.
ATP Count: 4ATP (2 from glycolysis, two from Krebs Cycle)
ELECTRON TRANSPORT CHAIN
Remember those NADH that the Krebs Cycle made from NAD+? These are electron carriers that drop off their H+ protons to the enzymes in the mitochondrial membrane. The enzymes are arranged in increasing electronegativity, so when the electron is dropped off by the NADH at the first enzyme, it passes through molecules that are more electronegative than the electron itself. This creates a proton gradient, as this passage of the electron allows for free-roaming H+ protons inside the mitochondrial matrix to make their way into the intermembrane space and create a gradient for ATP synthesis to occur.
After the electron makes its way through the electronegative enzymes, it arrives at the final enzyme, where an O2 molecule awaits. The final enzyme fuses the O2 molecule and final electron together, creating H20. Thus, we can say that O2 is the final electron acceptor in the electron transport chain.
Now that we’ve dealt with the electron, let’s see what happens to the gradient it created. The H+ protons in the mitochondrial matrix now make their way to the nearest ATP Synthase molecule, which is the place where ADP + Pi come together to fuse into ATP. The protons enter the ATP Synthase enter through its opening on the side of the intermembrane space. Once inside, the synthase uses the energy in the proton to fuse the ADP + Pi that are waiting in its active site on the matrix side through substrate-level phosphorylation.
This is the final part of cellular respiration, and has the highest ATP yeild of all.
ATP Count: 36 ATP (2 from glycolysis, two from Krebs Cycle, 32 from ETC)
