Citric Acid Cycle

Hi. So this video is gonna be talking about the citric acid cycle also known as the Krebs cycle or the T. C. A. Cycle. So first I'm going to spend some time just doing an overview of the cycle. And then later we're gonna get into the exact nitty gritty of the steps. The citric acid cycle is a set of various reactions that occur after glycol icis which generates or create C. 02 and N. A. D. H. So pretty much how this happens is glycol isIS is going to create pyro pain umpire of eight eventually becomes this term called dick our box elated. Which you don't necessarily need to know unless you want to and are taking chemistry. But essentially what it means is it removes the car boxing group and that creates CO. Two and eventually leads to the creation of a single Coetzee. So a C. Delco way is the starting molecule for the citric acid cycle. And um how it is created is through a complex known as the pyro bait dehydrate and this is the group of proteins that are responsible for taking piru and turning them into the sea broke away so that it can be used for the citric acid cycle. So what's acetyl coa has created the citric acid cycle then uses it oxidizes it to generate or produce or whatever one GTP three N. A. D. H. And one F. A. D. H. Two. And so um out of these three the N. A. D. H. Is then passed on to the next step of cellular respiration which is the electron transport chain. And I used to produce a P. P. So throughout all these we've been talking about whether or not these cycles require oxygen or use oxygen. So the citric acid cycle actually does auction but it does so indirectly. So the citric acid cycle itself doesn't use oxygen but it's still classified as an Arabic reaction because it needs to have N. A. D. Plus to run and oxygen is required for the regeneration of the N. A. D. Plus. So this is very similar to some of the other things that we've talked about in previous videos. So here's an overview of the citric acid cycle. You don't need to know any of these words in this video will go over them all in the next one. But you can see here that you start off with the ceo coo way, it's kind of the circular cycle. But it ends up creating th it creates GDP. Here's some F. A. D. H. Two. Here's some more N. A. D. H. Um And throughout this, oxygen isn't were not needed directly but it is needed because oxygen replaces in A. D. A. Plus which is then used to create the N. A. D. H. So there's the overview of the citric acid cycle. Let's now move on and get into the nitty gritty

So now we are going to get more into the exact steps of the citric acid cycle. So this is set up in similar ways. Other previous videos where the important stuff to know is here Bold ID. Um and these reactions are just provided just so that it's easier to understand the text if you don't necessarily need to be able to write out all these reactions. That's for your chemistry class. But the text is going to be important and I'm going to point out which steps are most important. So the first thing that is the first step is obviously very important because it's always the first. And what happens is um a Sudoku way is eventually turned into this molecule called citrate. And in the process of that the Coetzee is actually released. So the first step is the important part is the creation of citrate. Then that citrate begins to be used in other steps. So the second step is an ice elaboration step which just means that atoms are rearranged. So um the molecule that undergoes acceleration is called hydroxyl. So we have our citrate which we're starting with then there are these intermediate products that happened. And um the hydroxyl group has actually moved around and I summarized to a different location. And so you can see here that there's a water molecule that's lost but it's eventually added back in. So three is gonna be a really important step. And that's going to be carbon dioxide and N. A. D. H. Creation. So how this happens is the carbon oxidation. So we start out with our this molecule called ISIS situate. You don't need to know the molecule, but eventually N. A. D. Plus becomes N. A. D. H. And C. +02 is released and we're left with this molecule here. So this is a step three. This these words are really important. Step four is a second step of C. 02 and N. A. D. H. Creation. So pretty much the same thing happened. There's a second oxidation step which tends this molecule and creates EN A. D. H. And C. 02 into this one. Another important thing here is that there is this incoming C. O. A. Which gets added here on the end. Um But remember the important part isn't you know these exact chemical reactions. This is just an image of what I'm saying. The important part is this C. 02 and N. A. D. H. Creation the second time. So um The 5th step is gonna be the GTP creation here and again. You don't need to know these chemical names. But what happens is GDP comes in and G. D. P. Is release or made. And also the C. O. A. Is removed. So here it is and there is missing the six step is the F. A. D. H. Two creation. So this is gonna be a third oxidation step. So keeping keeping track of the steps that involves oxidation. So here we have this molecule, F A D. H two is created forms this molecule. and the third oxidation. Then we have a less important step and that's gonna be the addition of water and the water coming in changes the molecule a little and then we have step eight and that's gonna be in A. D. H. Creation. And so this is the fourth oxidation. So there are four oxidation events that happen and each time it creates a new energy molecule of some kind. So here we have N. A. D. H. So just to review and a scroll down, remember we started with pyro which came from like Alexis. This pyro bait was turned through the pyro bait di hydrogen. It's complex into acetyl coa a subtle cool way was then um put and turned into citrate which then circles through the citric acid cycle. And each one of these boxes are different enzymes that play a role in helping to convert these molecules. You don't necessarily need to know these enzymes names. Just know that they exist. Um And in that process we get a lot of things. We get GDP we get N. A. D. H. Um you know water is used up, there's all sorts of things that we get in the citric acid cycle

Which of the following is not a product of the citric acid cycle?

• A. NADH
• B. CO₂
• C. FADH₂
• D. Acetyle CoA

For each acetyl CoA that is oxidized in the citric acid cycle, what is created?

• A. 1 GTP, 3 NADH, and 1 FAHD₂
• B. 2 GTP, 1 NADH, and 3 FAHD₂
• C. 6 GTP, 2 NADH, and 1 FAHD₂
• D. 1 GTP, 1 NADH, and 1 FAHD₂

The citric acid cycle requires oxygen indirectly, because oxygen is necessary for what to occur?

• A. Replace FADH
• B. Replace GDP
• C. Replace ADP
• D. Replace NAD+

What is the starting molecule for the citric acid cycle?

• A. Glucose
• B. Pyruvate
• C. Acetyl CoA
• D. Citrate