Bioenergetics Flashcards
1
Q
∆ G
A
- The change in free energy associated with any given reaction.
- A spontaneous reaction is one that favours the production of products because the products produces will be at a lower energy level than the reactants
- Negative ∆G means that a reaction should be spontaneous and favours moving forward
- A balance between reactants and products is known as an equilibrium constant.
- A reaction that is at equilibrium can react either forwards or backwards to achieve that preferred equilibrium balance.
2
Q
Spontaneous Reaction
A
- Prone to consuming reactant, and will spontaneously make more products.
- In terms of equilibrium, that means that the Keq > 1, since the products are favored over reactants.
- Keq > 1 → at equilibrium there will be more products = spontaneous = negative ∆G
3
Q
Non-Spontaneous Reaction
A
- ∆G is positive
- Forwards reaction is not favoured and thus non-spontaneous
- Reverse reaction is favoured and spontaneous
- Keq < 1
- Most biological reactions do not start off at equilibrium, and sometimes even those reactions that are at equilibrium, we want to take out of equillibrium and drive towards products or reactants as the body needs.
4
Q
Non-Equilibrium Conditions
A
- When the concentrations of products and reactants are not at equilibrium, we can’t use Keq because thats the equilibrium constant.
- Q is then used which is the same as Keq, but it is not at equilibrium.
- If Q < Keq → ∆G < 0
- This means that we have less numerator, that is less product than the reaction wants.
- Forward reaction is sped up to work towards equilibrium
- If Q > Keq → ∆G >0
- There is too much numerator, which is too much product and the reverse reaction is favoured.
5
Q
Free Energy in Non-equilbrium Conditions
A
- ∆G = ∆G0 + RTInQ
- ∆G0 = Standard Gibbs free energy change for the reaction at equilibrium
- R = Ideal Gas constant (8.314J/K⋅mol)
- T = Temperature
- InQ = Natural log Q
- ∆G (left side) = the one that applies on the non-equilibrium concentrations
- ∆G0 = - RTInQ (at equilibrium)
6
Q
Non-spontaneous reaction to spontaneous reaction
A
- To cause a non-spontaneous positive ∆G reaction to occur is to pair that non-spontaneous reaction with another reaction that is highly spontaneous, so that the net reaction overall is still spontanteous.
- This relates to the conservation of energy
- Energy can not be created from nothing but we can borrow energy from another reaction to drive a non-spontaneous reaction
7
Q
ATP Hydrolysis
A
- “breaking” with the consumption of water
- In ATP hydrolysis, the last phosphate group is broken off
- This reaction has a standard ∆G = -30.kJ/mol
- One mole of ATP can power about 30kJ/mol of another reaction that would not be spontaneous on its own
- Referred to as the “energy currency of the cell”
- It makes it possible for many cellular processes to happen in the first place
- Without the high energy released from ATP hydrolysis, these reactions simply would not occur.
8
Q
Coupling
A
- Coupling a reaction with a negative free energy change to one that has a positive free energy change to push the non-spontaneous reaction forward.
9
Q
What makes ATP an Ideal Energy Currency
A
- The phosphate groups in the structure of ATP are the main reason for ATP’s energy.
- The phosphoanhydride bonds or P-O bonds, are really unstable and to even make ATP in the first place takes a lot of energy.
- Think back to the electron transport chain in the mitochondria. A full ATP synthase pump was needed to make ATP
- Due to the unstable high-energy P-O bond, ATP is always ready to break off that last phosphate group and transfer to a reactant molecule.
- The instability of ATP is what helps drive non spontaneous reactions
- On the other hand, adding a phosphate group to a reactant molecule is usually non-spontaneous because of the phosphorylated product itself becomes very unstable. This is why phosphorylation needs to be couples with ATP hydrolysis.
- Another key role ATP can play in cells is to activate or deactivate enzymes or proteins which can directly or indirectly control key biological functions.
- Anytime ATP transferes its terminal phosphate group to another molecule or enzyme, this process is called phosphorylation and this can be thought of as an on/off switch depending on the enzyme that gets phosphorylated.
10
Q
Sugars
A
- Sugars are chains of carbon atoms with hydroxyl groups on most of the carbons and a carbonyl group on one of the carbon atoms in the chains.
- A carbonyl is a carbon doubly-bounded with an oxygen, and for sugars, will either be an aldehyde, like in glucose or a ketone, like in fructose.
- Triose sugars (C3H6O3) → three carbon sugar
- Tetrose sugar (C4H8O4) → four carbon sugar
- Pentose Sugars (C5H10O5) → Five carbon sugar
- Glucose is an example of an aldehyde-hexose, or aldohexase
- Glucose is a six-carbon chain with an aldehyde in the C-1 position and with a hydroxyl on all other carbons.
- When the ring bends around, the aldehydyde carbon is attacked by the oxygen on a hydroxyl group and the chain becomes a ring.
- The most stable rings are those containing six members.
- These rings are not flat, as the stability or lack thereof of certain member can draw them closer together or push them farther apart (steric hindrance).
- This interaction results in what is commonly called a chair or bat formation for hexoses.
- Penoses can form an envelope with their rings.
11
Q
Enantiomers and Diasteromers
A
- No matter what we begin by comparing two organic molecules that have the same chemical composition, same bonds, same molecular weight. Due to their configurations, the two molecules cannot have any functional groups rotated around any single bond to look like one another
- The carbon must have four different functional groups attached to it.
- Any molecule that has this arrangment is referred to as chiral.
- If there are one or more chiral (chiral centers) then is might be possible that one molecule is the exact mirrored attachment those four different functional groups.
- The perfect mirrored pair are called enantiomers
- Diastereomers, on the other hand, have two or more chiral centres, and this allows a particular issue to arise. While it is possible that a molecule with multiple chiral carbons could be paired to its mirror image match, it is also possible that one or more of the chiral centres is not the mirror image, and even if other are this is still called a diastereomers
- Diastereomers have at least one (but not all) chiral carbons in inverted configurations.
12
Q
Epimers
A
- Epimers differ in absolute configuration at exactly one chiral carbon.
- Some chiral compounds can be classified both as diastereomers (broadly) and as epimers (more specifically
13
Q
Anomers
A
- Anomers are epimers in which the two cyclic forms differ in the configuration of the anomeric carbon.
- Another example is the 6 carbon sugar
- Glucose is the sugar found in cells
- Fructose is teh sigar found in fruit
- Galactose is often found in dairy products
- Glucose and fructose are found as pure substances or combined with other sugars
- Galactose is usually found in combination with other sugars
- Between glucose and fructose, a rather significant difference may stand out: the carbonyl group is in a different location of the chain
- This means that fructose and glucose two are actually another class of isomers entirely, a structural isomer.
- It takes breaking and reforming bonds in a new position to go from one to the other structure.
- With glucose and galactose, the bonds are all the same and in the same carbon position, but not the same spatial arrangement exactly. They are C-4 epimers, with the hydroxyl in a different side of the C-4 carbon, but all the other chiral carbons exactly equivalent.
14
Q
Absolute Configuration
A
- Nomenclature system used for three-dimensional arrangements of atoms in isomer; the most common systems are D/L and (R)/(S)
- Using fisher projection, D- sugars have the OH on the right and L-sugars on the left
- D-glucuse is used to fuel our cells, but L-glucose is hard to find in nature
15
Q
Monosaccarides
A
- Glucose, Fructose and Galactose are examples of sugars that are monosaccarides, which are single chains or rings of carbon atoms.
- On the contraty, bigger sugars can be composed of multiple subunits as well.
16
Q
Sucrose
A
- What table sugar is called
- Is a disaccharide
17
Q
Oligosaccharide
A
- Adding more sugar subunits takes the naming from a disaccharide to an oligosaccharide
-
Think:
- Monarchy → ruled by one; mono means one
- Oligarchy → ruled by a small group of people; oligo means a few
18
Q
Polysaccharides
A
- Many sugars
- Think a polygon has many sides, “poly” means many
- Polysaccharides are carbohydrates that consists of many sugar molecule bonded together.
- A common polysaccharide is cellulose, the long chain molecule found in trees and other plants
- The cellulose in your popcorn is polysaccharide, but so is the stratch in the popcorn.
19
Q
Starch
A
- Very similar in structure to glycogen (a way that the body also perfers to store sugar)
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20
Q
Glycosidic Linkage
A
- Is a way to describe the covalent bond between a saccharide bonded to another group.
- When the covalent bond that joins the carbohydrate is challenged by the introduction of a water molecule, hydrolysis occurs, breaking the covalent bond and adding a hydrogen to one new product molecule and a hydroxyl to the other
21
Q
Sugars and Enzymes names
A
- -ose = sugar
- -ase = enzyme
- Lactose is broken down by lactase → Glucose + Galactose
- Maltose is broken down by maltase → Glucose
- Sucrose is broken down by sucrase → Glucose + fructose
22
Q
Glycolysis
A
- The process of breaking down glucose
- Glycolysis breaks down glucose, a six carbon sugar into two pyruvates (each having three carbons)
- To breakdown glucose we need some energy, which can be done by 2 ATP molecules
-
Why do we break down glucose?
- So that we can get more energy out than we put in; 4 ATP + 2 NADH molecules
- Net Reaction: Glucose + 2 ATP → 2 Pyruvates + 4 ATP + 2 NADH
- There are 10 steps of glycolysis, but 3 parts:
- Step 1: Energy Input
- Step 2: Cleavage
- Step 3: Energy Output
23
Q
Step 1: Energy Input
A
- This stage covers the first 3 steps:
- We know that we have to use up 2 ATP in these first 3 steps.
- ⅔ steps will be phosphorylation of glucose by ATPs
-
First Step:
- The enzyme hexokinase transfers a phosphate group from ATP to glucose creating Glucose 6-phosphate
- Hexokinase catalyzes one of the 3 irreversible steps of glycolysis
-
Second Step:
- Is an isomerization, converting G-6-P into fructose 6-phosphate
- Just like that the first carbon becomes easily accessible for phosphorylation
-
Third Step
- Phosphofructokinase 1 (PFK-1) transfers a phosphate group from ATP to glucose creating Fructose 1,6-bis Phosphate
- PFK-1 is an important enzyme, not only because it catalyzes another one of the irreversible steps of glycolysis, but also because it is the rate-limiting enzyme of the entire pathway.
- This means that if the cell needs to regulate glycolysis, it can do so by acting on PFK-1.
24
Q
Fructose 1,6 Bisphospate
A
- One think that is notable is that it is almost symmetrically, as if it is waiting to be split in two.
- The second thing to notice is that there are two phosphate groups on either side of the molecule
- recall from organic chemistry that phosphate groups are negatively charged and -ve charged especially those close together, say on the same molecule, strongly repel one another.
- This intramolecular repulsion makes fructose 1,6 bisphosphate extremely high-energy and extremely unstable, which leads to the next stage of glycolysis, CLEAVAGE.
26
Q
Step 3: Energy Output
A
- Each of these steps happens twice, one for each molecule of GAP
- At this point we have 2 molecules of gap which will become 2 pyruvates, but we do not have ATP to NADH
- This means that as each GAP molecule is convereted into pyruvate, it must also produce 2 ATPs and 1 NADH
-
Step 6:
- Is a redox reaction that produces NADH molecule while also adding in an inorganic phosphate to GAP, producing 1,3-bisphosphoglycerate
- This molecule is highly unstable
-
Step 7:
- A phosphate group is removed producing out first ATP molecule, as well as the product, 3-phsophoglycerate.
-
Step 8 and 9:
- Isomerizations that produce out penultimate product, phosphoenolpyruvate, or PEP.
-
Step 10:
- The conversion of PEP to pyruvate
- This step is catalyzed by the enzyme pyruvate kinase
- This enzyme is the last step of glycolysis.
- It is the last irreversible step where we generate our last final ATP molecule, bringing us to 2 ATPs per GAP molecule
- Overall this means that glycolysis produces 4 ATP molecules, 2 pyruvate and 2 NADH all from 2 ATPs and 1 glucose molecule.
28
Q
Lactic Acid Fermentation
A
- A pathway that transforms pyruvate into lactic acid with and 2 NAD +, therefore regenerating the NAD+ levels
30
Q
Step 1 of Gluconeogenesis
A
- We first start with pyruvate, then have to convert it into PEP
- As we know the PEP → pyruvate step was an irreversible, one way trip, so the cell has to find a detour to get back to PEP, which is done by converting pyruvate into Occeloacetate (OAA), which can then be converted to PEP.
31
Q
Step 2 of Gluconeogenesis
A
- From there, the glycolytic steps run in reverse, uring the same enzymes until we get to the last three steps of gluconeogenesis, also known as the first three steps of glycolysis.
- In glycolysis, hexokinase and PFK-1 phosphorylate glucose to produce fructose 1,6-bisphosphate, while in gluconeogenesis, this runs in reverse, as fructose 1,6-bisphosphate has its phosphate groups removed by fructose 1,6-bisphosphatase and glucose -6 phosphatase, yielding sugar.
32
Q
Pentose-5-phosphate Pathway (PPP)
A
- Heavy reliance on glycolytic intermediate
- This pathways takes glucose 6-phosphate, the first intermediate of glycolysis, off the glycolytic path to produce two important molecules: Ribose-5-phosphate, a building block of nucleic acids and NADPH, a versatile building block used to create a variety of compounds, such as cholesterol.
- If we were to count the carbons throughout the pentose-5-phosphate pathway, we start with the six carbons of G-6-P, but are only left with the five carbons of ribose-5-phosphate.
- The missing carbon is lost as the waste product, carbon dioxide. So this means that like other pathways that produce CO2 like CAC or pyruvate decarboxylation, the pentose-5-phosphate pathway is an oxidative process.
34
Q
Citric Acid Cycle
A
- 8 steps of the citric acid cycle
- A sugar has just progressed through glycolysis and generated 2 pyruvate, a natural recycling champion, out bodies want to change those pyruvate unto acetyle-CoA.
- The pyruvate dehydrogenase complex does this through oxidative decarboxylation (remove CO2, but add a sulfur in instead).
- The oxidation part comes from sulfur being more oxidizing than carbon.
- In the end, we form a high energy thioester bond between Coenzyme A and the acetyl group.
-
Mnemonic: “Can I Keep Selling Seashells For Money, Officer?”
- C → Citrate
- I → Isocitrate
- K → a-ketoglutarate
- S → Succinyl-CoA
- S → Succinate
- F → Fumarate
- M → Malate
- O → Oxaloacetate
35
Q
Step 1 of the Citric Acid Cycle
A
- In this first step, Acetyl-CoA from pyruvate dehydrogenase is combined with oxaloacetate to produce citrate.
- Citrate is the ion that is formed when citric acid loses all of its acidic hydrogen.
- This step happens to be where the citric acid cycle gets one of its names. When a Acetyl-CoA directly reacts with oxaloacetate, the acetyle group combones with the carbonyl carbon on oxalacetate forming the intermediate citryl-CoA.
- Water then hydrolyzes off the CoA, leaving behind our citrate molecule.
- To drive this condensation reaction forwards, our bodies enlist the help of the enzyme: citrate synthase. (responsible for synthesizing citrate)
- A Synthase is any enzyme that is able to modify or make a thing without the input of outside energy. Instead it releases energy
- This particular part of the reaction is an irreversible step since the reaction is so highly exergonic, or energy releasing.
39
Q
Step 5 of the Citric Acid Cycle
A
- Succinyl-CoA needs to be broken down to gain some energy
- Succinyl-CoA is broken down by Succinyl-CoA synthetase, using water to hydrolyze it.
- A Synthetase creates a new covalent bond using a bit of energy
- In this case, the energy comes from breaking that high energy thioester bond, and we can now form the phosphorylation of GDP to GTP.
- Adding a phosphorus is called phosphorylation
- This GTP can later transfer its phosphate group to an ADP molecule. This results in the production of our first molecule of ATP
- This is the only place in teh citric acid cycle where substate-level phosphorylation occurs.
- Substrate-level means that ATP is produced without using ATP synthase
- The coenzyme-A product will be used in other places around the cycle, but the substrate succinate is what moves on to step 6.
41
Q
Step 7 of the Citric Acid Cycle
A
- We take fumarate and form malate, with the enzyme fumarase though a hydration reaction
- Water is added across the double bond, breaking it.
- Water’s hydroxyl group and hydrogen separate to either end, satisfying both sides.
- This could in theory, results in different stereochemistry, but in the citric acid cycle only the L-malate enantimoner is formed.
- This is because the enzyme holds the molecule in only one orientation during the reaction.
43
Q
Understanding Carbon Numbers Step 1
A
- The citric acid cycle is all about harvesting energy, while shifting around carbons.
- If we start at step 1, with the four-carbon oxalocetate, it reacts with the two-carbon acetyl-CoA to form a six-carbon citrate.
- Three of our carbons make up carboxylic acid groups, which is where the name tricarboxylic acid cycle comes from
- But since this is a cycle and if we originall need a four-carbon molecule to get to a six-carbon molecule, then our cycle has to find a way to cleave off those extra carbons to get back to our four carbon starting point.
- Ideally, this would happen while we harvest some energy.
44
Q
Understanding Carbon Number Step 2
A
- We have primed our citrate for decarboxylation by isomerizing it.
- We are still six-carbons long, but that will change in step 3
45
Q
Understanding Carbon Number Step 3
A
- When that decarboxylation reaction occurs in step 3, one carboxylic acid group forms carbon dioxide, turning our six-carbon citrate into a five-carbon alpha ketoglutarate.
- In the process we also formed the first NADH energy carrier.
46
Q
Understanding Carbon Number Step 4
A
- Step 4, once again goes through a decarboxylation, turning another carboxylic acid group into our final carbon dioxide molecule, while also harvesting energy by reducing NAD+ to NADH.
- At this point, we are back to a four-carbon molecule, but we havent squeezed out as much energy as we can. That is why duding the decarboxylation reaction the alpha-ketoglutarate dehydrogenase complex added a Coenzyme-A with a high energy thiol group, to attach onto the chain, generating succinyl-CoA.
47
Q
Understanding Carbon Numbers Step 5
A
- Hydrolyzing this thioester bond is used to phosphorylate GDP to GTP, which will later on, down the line, form ATP
- Recall that, this is the only step where we directly generate our energy currency, ATP without ATP synthase
48
Q
Understanding Carbon Numbers Steps 6,7 and 8
A
- We essentially follow a path to reform oxaloacetate for steps 6, 7 and 8
- In Step 6, FAD is reduced to FADH2 to really pull out every little bit of energy.
- In the processs, succinate becomes fumarate, still having only four-carbons but now, the alkene structure has a double-bond.
- This double bond sets us up for one last wave to squeeze out energy
- In Step 7, by adding water in a hydration reaction, that double bond is broken to a single-bond, forming the alkane for carbon-chain malate.
-
Step 8 is that final oxidation to form a carbonyl from the hydroxide group
- Whenever there is an oxidation reaction, there must always be a reduction reaction somewhere else.
- In this case, that reduction reaction turns into NAD + into one last molecule of NADH.
- So if we were to tally up everything, we came back to a four carbon molecule, we generates two molecules of Co2 which we are literally breathing out, energy has stored in three NADH and one FADH2 molecules, and we directly formed one molecule of ATP from GTP.
49
Q
Total Carbons Citric Acid Cycle
A
- Energy is really just currency exchange
- 1 NADH = 2.5 ATP
-
1 FADH2 = 1.5 ATP
- = 1 Pyruvate = 10 ATPs
- Since each glucose originally generates two molecules of pyruvate, we need to multiply this by 2 = 1 glucose = 20 ATPs from the citric acid cycle.
- The 2 NADH formed from the pyruvate dehydrogenase complex we generated acetyl-CoA to even start the cycle. That gets us another five ATP technically, so we’re now up to 25 molecules of ATP
- Since one molecule of glucose should generate between 30 to 32 ATPs depending on the cell, some bonus ATPs mist be coming from glycolysis directly.
- Carbons are key to understanding where the energy is going.
51
Q
Allosteric Binding
A
- Is when we have another effector molecule binding at a site on an enzyme, other than its active site
- This often leads to some form of conformational change, which for our purposes inhibits the function,
- The first site along the cycle is at citrate synthase, step 1.
- At this step, there are four direct allosteric inhibitors: ATP, NADH, succinyl-CoA, and citrate.
- That means that if there is too much of any of those, it will inhibit citrate synthase, and without citrate, the following steps could not happen.
- The next site for regulation is at isocitrate dehydrogenase, step 3.
- In this step ATP and NADH are allosteric inhibitors.
- The last site along the cycle for regulation is at the alpha ketoglutarate dehydrogenase enzyme in Step 4
- ATP, NADH, and succinyl-CoA are our inhibitors here
- There is a pattern: high levels of ATP and NADh inhibit the cycle across all three regulation sites.
- But when our bodies are metabolically active, we’re using up ATP and NADH yo fuel whatever we’re doing. As a result, we end up with more ADP and NAD+
- This turns the enzyme at these checkpoints back on.
- Following Le Chatelier’s principle, out body will compensate to get back to homeostasis, increasing the production of ATP and NADH.
53
Q
Electron Transport Chain Machinery
A
-
Cristae:
- The folds in the membrane that serves to increase the membrane surface area, which makes room for more Electron Transport Chains.
-
Electron Transport Chain
- A series of four membrane-bound complexes that facilitate redox reactions in order to transfer electrons down the chain until they reach their final electron acceptor, oxygen
- Redox reactions involve the movement of electrons AND protons
- The goal of the ETC is to use the flow of electrons to push protons across the inner mitochondrial membrane and into the inter membrane space.
- But protons are unhappy out there, since it can get really crowded and they really want to come back in.
- This generates the iconic proton gradient that literally couples or connects the ETC to ATP synthase, and the second part of the OXPHOS.
54
Q
NADH-Coenzyme Q Oxidoreductase (Complex I)
A
- It oxidized NADh to reduce Coenzyme Q with the help of two of its subunits in particular, a flavoprotein, flavin mononucleotide (FMN) and an iron-sulfur complex.
- These subunits just help transfer electrons from one molecule to another
- The oxidized form of NADH?
- Recall that oxidation involves the loss of an electron
- This makes the molecule more positive, forming NAD+
- Coenzyme Q also goes by the name ubiquinone, which is a ketone, so when it is reduced it forms the alcohol, ubiquinol, which if you think about organic chemistry makes sense because the reduced form of a ketone is an alcohol, and we’re adding hydrogens.
55
Q
Succinate-Coenzyme Q oxidoreductases (Complex II)
A
- It is involved in the transfer of electrons to coenzyme Q
- Again, an iron-sulfure protein and the flavoprotein, flavin adenine dinucleotide (FAD), are involved but there are two differences between complex I and II
- The first difference is that complex I gets its electrons from NADH, while complex II gets its electrons from FADH2, which is generated by oxidizing succinate → an intermediate in the citric acid cycle.
- The second difference is that no proton pumping occurs at complex II. FADH2 does not increase the proton gradient, which later explains why FADH2 yeilds less ATP than NADH.
- But it still plays an important role in transferring high-energy electrons from succinate to CoQH2.
56
Q
Coenzyme QH2-cytochrome c Oxidoreductase (Complex III)
A
- Its oxidizing CoQH2 and transferring those electrons to cytochrome c, in other words reducing it.
- The cytochrome in this case is important because its the heme protein that contains the iron atom that’s needed to transfer the electrons and spit out the proteins into the inter membrane space
- DDT comes in and disrupts the transfer of our substrate CoQH2, messing with both complex II and complex II in the chain.
- All that we need to know is that DDT can come in and tamper with the proton gradient, ruining the coupling of the electron transport chain to ATP production in part 2 of OXPHOS
57
Q
Cytochrome C Oxidase (complex IV)
A
- This complex contains other cytochromes and copper, which facilitates the oxidation of cytochrome c and the reduction of our final electron acceptor oxygen to form water.
- This is where the last couple of protons are pumped across the membrane into the intermembrane space.
58
Q
Part 2 of OXPHOS
A
- After generating a bunch of unhappy protons, all crowded together in the intermembrane space part 2 can occur
- As a result of all the protons in the intermembrane space, the pH drops in the intermembrane space and the voltage difference between the INNER membrane and the INTER membranr space is increased. This is how we get that electron-chemical gradient
- It involves both chemicals (our protons) and electrostatics (the change in voltage), which is sometimes regerred to as the proton-motive force.
- This force is harnessed by complex V, which is commonly known as ATP synthase.
- The protons rushed through the ion channel portion of ATP synthase, through a processes called chemiosmosis.
- It is important to stress here that the protons are passing a semi permeable membrane via facilitated diffusion; it’s just using the chemical gradient
- Now as the protons travel back into the matrix, they’re taking advantage of another structure of ATP synthase that acts like a turbine.
- Protons push through the ion channel spinning this turbine
- Their torque or force caused by the rotation of this turbine powers another pocket of ATP synthase that holds together a molecule of ADP at a phosphate group, forcing them together to from ATP.
- It takes 4 protons to form 1 ATP molecule and when going through the Electron Transport chain, Complex I and III each generated 4 protons, while Complex IV generated 2 protons.
- Since we get a total of 10 protons from each molecule of NADH and 6 protons from each molecule of FADH2, we’re getting about 2.5 ATP per molecule of NADH and 1.5 per molecule of FADH2.
- When we take a step back, we harvested 10 NADH and 2 FADH2 from glycolysis, pyruvate decarboxylation and the citric acid cycle. So this translates to 28 molecules of ATPO from our carriers.
- The other 2-4 molecules of ATP that get us to the commonly notes 30-32 molecules of ATP, pending on tissue type, come directly from glycolysis and the citric acid cycle.
