Question

1. Specifically explain how ETC/ATP synthase generates 28-34 ATP (with respect to electron carrier molecules) and how the entire process of aerobic glucose metabolism generates 32-38 ATP

Answer 1

Cellular respiration can be aerobic or anaerobic.Anaerobic respiration makes a total of 2ATP.Aerobic is much more efficient & can produce up to 36-38 ATP with a single molecule of glucose.
A scientific term for sugar is glucose and the chemical formula for glucose is C6H12O6. We need O2 + C6H12O6 for energy to stay awake, just like we need O2 + C6H12O6 in order for cellular respiration to take place.
C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP
Glycolysis is the first step in cellular respiration for both anaerobic and aerobic processes. Glycolysis takes place in the cytosol of a cell. In the cytosol we convert 1 molecule of glucose into 2 molecules of pyruvate. Of course glucose can’t be converted into pyruvate without a little bit of help. This conversion requires 2 NAD+ and some energy, in the form of 2 ATP. Once glycolysis is completed, we are left with 2 pyruvate, 2 NADH, and 4 ATPs as products. Since glycolysis yields 4 ATP, but we had to use 2 ATP in the beginning of the process, the total Net Gain of energy is 2 ATP. The cell will use the 2 ATP for energy. NADH will be recycled back to NAD+ in a future process so that it can be used in glycolysis again. The 2 pyruvate molecules will be used for the second step of cellular respiration.

The Krebs cycle is the second step in aerobic respiration and takes place in the matrix of the mitochondria (middle of the mitochondria).
We start with one of the two pyruvate molecules that were made in the cytosol of the cell during glycolysis. The pyruvate molecule enters the matrix of the mitochondria where it is converted to acetyl CoA. Acetyl CoA is responsible for initiating a cyclical series of reactions. Acetyl CoA creates the first compound in the Krebs cycle (Citrate) by enzymatically transforming the very last product formed in Krebs cycle, Oxaloacetate, into Citrate.
Every time through the Krebs cycle, 1 ATP molecule is created and 3 molecules of carbon dioxide, CO2, are released. Since only 1 pyruvate is needed to circle through the Krebs cycle and 2 pyruvate molecules were formed during glycolysis, the Krebs cycle is repeated. This means during cellular respiration, six carbon dioxide molecules are release and the Krebs cycle forms 2 additional ATP. Through the first two steps of cellular respiration there is a net gain of 4 ATP. Although the Krebs cycle doesn’t provide much energy, it does yield several molecules of NADH and FADH2. These two molecules will be the key to producing many more ATPs in the third step of cellular respiration, the electron transport chain.

The third and final step of cellular respiration takes place in the inner mitochondrial member and is called the electron transport chain (ETC).
The ETC takes place within the innermost membrane. Often the term oxidative phosphorylation is used interchangeably with the electron transport chain; however, oxidative phosphorylation is the series of reaction that takes place during the ETC.
Conclusion-
At the end of the ETC, water (H2O) and ATP is made. Depending on how many NADH molecules are available, the electron transport chain makes a total of 32 or 34 ATP. These 32-34 ATP combined with 2 ATP from glycolysis and 2 ATP from the Krebs cycle means that one molecule of glucose (sugar) can make a total of 36-38 ATP.

The electron transport chain (ETC) is the final step of cellular respiration and takes place in the mitochondrion. During this stage, the high-energy electrons gathered by NAD+and FAD from the previous stages are used to convert ADP into ATP.
The process takes place in the inner mitochondrial membrane. NADH and FADH
2, generated by glycolysis and the Kreb's cycle, deposit their electrons into the transport chain. They can then go gather more electrons.

The deposited electrons are transported to different carriers. Their energy is used to create an electrochemical gradient (a proton gradient) by pumping protons across the membrane.

There are 4 major complexes in the chain. The electrons are passed through Complex I and II first. As this happens, protons are pumped across the inner mitochondrial membrane and into the intermembrane space.

A carrier called Ubiquinone Q picks up the electrons and takes them to Complex III. When the complex accepts the electrons, it is able to pump more protons across the membrane.

Next, another carrier, Cytochrome C, picks up the electrons and takes them to Complex IV. In this complex, oxygen becomes the last electron acceptor. The reaction between the oxygen and electrons creates water and pumps more hydrogen ions across the inner membrane.
The intermembrane space gains a positive charge from all the hydrogen ions, while the matrix gains a negative charge.
Eventually, the charge difference between the intermembrane space and the matrix is too large. The protons have to cross back over the membrane to even things out. The positively charged hydrogen ions are forced through channels in the ATP synthase. This causes the enzymes to spin, grab onto ADP molecules, and stick another phosphate group to them, creating ATP.

Cellular respiration can be aerobic or anaerobic.Anaerobic respiration makes a total of 2ATP.Aerobic is much more efficient & can produce up to 36-38 ATP with a single molecule of glucose.
A scientific term for sugar is glucose and the chemical formula for glucose is C6H12O6. We need O2 + C6H12O6 for energy to stay awake, just like we need O2 + C6H12O6 in order for cellular respiration to take place.
C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP
Glycolysis is the first step in cellular respiration for both anaerobic and aerobic processes. Glycolysis takes place in the cytosol of a cell. In the cytosol we convert 1 molecule of glucose into 2 molecules of pyruvate. Of course glucose can’t be converted into pyruvate without a little bit of help. This conversion requires 2 NAD+ and some energy, in the form of 2 ATP. Once glycolysis is completed, we are left with 2 pyruvate, 2 NADH, and 4 ATPs as products. Since glycolysis yields 4 ATP, but we had to use 2 ATP in the beginning of the process, the total Net Gain of energy is 2 ATP. The cell will use the 2 ATP for energy. NADH will be recycled back to NAD+ in a future process so that it can be used in glycolysis again. The 2 pyruvate molecules will be used for the second step of cellular respiration.

The Krebs cycle is the second step in aerobic respiration and takes place in the matrix of the mitochondria (middle of the mitochondria).
We start with one of the two pyruvate molecules that were made in the cytosol of the cell during glycolysis. The pyruvate molecule enters the matrix of the mitochondria where it is converted to acetyl CoA. Acetyl CoA is responsible for initiating a cyclical series of reactions. Acetyl CoA creates the first compound in the Krebs cycle (Citrate) by enzymatically transforming the very last product formed in Krebs cycle, Oxaloacetate, into Citrate.
Every time through the Krebs cycle, 1 ATP molecule is created and 3 molecules of carbon dioxide, CO2, are released. Since only 1 pyruvate is needed to circle through the Krebs cycle and 2 pyruvate molecules were formed during glycolysis, the Krebs cycle is repeated. This means during cellular respiration, six carbon dioxide molecules are release and the Krebs cycle forms 2 additional ATP. Through the first two steps of cellular respiration there is a net gain of 4 ATP. Although the Krebs cycle doesn’t provide much energy, it does yield several molecules of NADH and FADH2. These two molecules will be the key to producing many more ATPs in the third step of cellular respiration, the electron transport chain.

The third and final step of cellular respiration takes place in the inner mitochondrial member and is called the electron transport chain (ETC).
The ETC takes place within the innermost membrane. Often the term oxidative phosphorylation is used interchangeably with the electron transport chain; however, oxidative phosphorylation is the series of reaction that takes place during the ETC.
Conclusion-
At the end of the ETC, water (H2O) and ATP is made. Depending on how many NADH molecules are available, the electron transport chain makes a total of 32 or 34 ATP. These 32-34 ATP combined with 2 ATP from glycolysis and 2 ATP from the Krebs cycle means that one molecule of glucose (sugar) can make a total of 36-38 ATP.

We can say ATP synthase acts as a channel protein, helping the hydrogen ions cross the membrane. It also acts as an enzyme, forming ATP from ADP and inorganic phosphate. After passing through the electron-transport chain, the “spent” electrons combine with oxygen to formwater. This is why oxygen is needed; in the absence of oxygen, this process cannot occur.
The two NADH produced in the cytoplasm produces 2 to 3 ATP each (4 to 6 total) by the electron transport system, the 8 NADH produced in the mitochondriaproduces three ATP each (24 total), and the 2 FADH2 adds its electrons to the electron transport system at a lower level than NADH, so they produce two ATP each (4 total). This results in the formation of 34 ATP during the electron transport stage.