Krebs Cycle Explained!

all right so we're gonna be talking about the krebs cycle today the krebs cycle basically comes right after aerobic glycolysis so this is within a cell if you just ate a doughnut you broke it down to a glucose molecule that glucose molecule split in half into pyruvate and that pyruvate is what's going to kind of start this Krebs cycle up so the way this fits in the big picture again guys it's glycolysis and then if you have oxygen oxygen is required because the Krebs cycle is in the mitochondria so if you have oxygen then you're gonna go to the mitochondria and then do the Krebs cycle it's kind of debatable whether the pyruvate to acetyl co a is within the Krebs cycle but we're gonna include it cuz most textbooks do pyruvate is that three carbon molecule it's half of the glucose so glycolysis cut in half now you have pyruvates and we're gonna break that down into acetyl co a it's a three carbon molecule here and then basically in the process of getting rid of a carbon that that was a high-energy bond so when you broke that bond and put that carbon onto an oxygen and then you exhaled co2 we also turned an nad plus into an NADH at this point we have a two carbon molecule and this is where we really start the krebs cycle where it becomes a cycle alright so acetyl co is that two carbon molecule from the very first step we're gonna combine a two carbon acetyl co a with a four-carbon oxaloacetate the two things combined is going to make citric acid and some people think this is so important they named the krebs cycle after the after it and call it the citric acid cycle so you might say that is another name but that citric acid now is going to go through a number of basically phosphorylations of these products here so we're gonna basically turn one product to into another and then that second product will be used later on in oxidative phosphorylation which we'll get to but this process of just kind of changing energy is what we're doing multiple times in in the rest of the Krebs cycle so to start off we're taking NAD+ to NADH that's gonna be the first one we're gonna do total of three times for one krebs cycle so one acetyl co a is gonna end up with three nadh --is so you'll see nadh here here and right there in the process we're also going to get rid of two carbon dioxides so we're gonna get rid of two carbons so again this was a six carbon we're gonna really get rid of two of them it's gonna be that co2 here and that co2 here that leaves us with a four carbon molecule to then come back up and basically continue around the cycle so total in the Krebs cycle guys we have three nadh --is and then there's actually a fourth one from up here so a total of four kind of three within the cycle that extra one here for nadh is they come out of the krebs cycle one fadh2 or fadh2 plus so one fadh2 and we also directly just get two ATP so to back up big picture here we got two ATP from glycolysis we have two ATP from the krebs cycle and then now we're going to continue with oxidative phosphorylation and that's really gonna be where we're gonna get most of our ATP so over here we're looking at now we have ten nadh is this is where those nadh is we're gonna kind of finally cash in on them and actually turn them into ATP so we had nadh four of them were from from the krebs cycle again we have two pyruvates so we have two pyruvates each of those is going to be for nadh --is so if we think about that for here two times that's going to get us eight and then another two of them were actually from glycolysis so that's a total of ten nadh is that we have that we kind of stored up and now we're going to turn those into energy so we're gonna multiply those by three because we actually get three ATP per nadh molecule the other part of oxidative phosphorylation is going to be turning these fa da cheese into energy we have two fa d HS multiply that by two ATP per one of those molecules and it's going to get four we have 30 80 people s 480p is going to give us 30 480p just from oxidative phosphorylation and if we combine that with a 2 net from glycolysis and the 2 ATP from the Krebs cycle we get a total of 38 ATP I do want to add one thing here guys this is a little bit outside of the scope of like cellular respiration but fat can actually go through its own process a beta oxidation and break basically a giant fat molecule with a triglyceride backbone and a bunch of fatty acids all the way down those fatty acids can break down into acetyl co a molecules and they can just jump in right here so fat if you have one molecule it's kind of separate from glucose it'll actually produce a ton of ATP like over 300 ATP but this is kind of where it enters the process and kind of gets mixed in with this part of bioenergetics alright guys I hope you found this video helpful and understanding the Krebs cycle if you did go ahead and smash the like button and also subscribe because I have awesome videos like this coming out all the time so thanks for watching guys

Channel: The Movement System

Views: 58,258

Keywords: krebs, Krebs cycle explained, bioenergetics, exercise science, glycolysis, glycolysis explained, citric acid cycle, citric acid cycle explained, kinesiology

Id: 3Unl69yHiEk

Length: 5min 32sec (332 seconds)

Published: Sun Jan 19 2020