해당 과정: 세포에서의 ATP 생산 및 NADH 생성

### 해당 작용의 이해: 세포 호흡의 초기 단계
* 🔬 해당 작용은 **세포 호흡의 첫 단계**로, 진핵 세포와 원핵 세포 모두에서 발생하며 **세포질에서 일어난다**.
* ⚙ 해당 과정의 다단계 과정에는 각 반응을 촉매하는 특정 효소가 관여하며, 대부분의 효소 이름은 **"ACE"로 끝납니다.**
* ⚡ 전반적인 세포 호흡 과정에는 산소가 필요하지만, 해당 작용은 그렇지 않고 대신 **포도당 분자당 두 개의 ATP 분자를 순증가**시킵니다.
* 🔢 탄소 6개 분자인 포도당은 해당 과정에서 **탄소 3개 화합물(피루브산)로 분해**되며, 탄소 보존을 위해 각 단계를 추적합니다.
* 🔋 해당 작용은 ATP 생성 외에도 세포 호흡의 후반 단계에 중요한 전자 운반체 역할을 하는 **NADH 분자**를 생성합니다.
* 💡 "따라서 이것은 마지막에 피루브산염이며, 포도당 분자 하나에서 두 개의 피루브산염이 있다는 것을 알 때 **하나의 3-포스포글리세레이트 분자에서 추적하는 것**이므로 하나의 피루브산염만 표시된다는 것을 기억하세요."
* 🔄 각 포도당 분자에 대한 해당 과정의 전반적인 결과는 **피루브산 분자 2개, ATP 순 증가량 2개, NADH 분자 2개**가 생성되는 것입니다.
* NADH가 운반하는 전자는 **해당 과정 중 포도당 결합이 분해되는 과정**에서 파생되며, 이후 세포 호흡 과정에서 그 역할을 수행합니다.

해당 작용은 진핵 세포와 원핵 세포 모두에서 일어나며, 전자 운반체로서 ATP와 NADH를 생성합니다.

OK, so moving forward in our discussion of cellular respiration, we're going to talk in detail about the first process that's called glycolysis. And glycolysis occurs in the cytoplasm of the cell. So I want to make sure we understand that this is happening in eukaryotic cells and this is happening in prokaryotic cells. So the other thing that's important, even though the overall reaction of cellular respiration requires oxygen, this portion does not require oxygen. Now, let's get into the details. So we have multi-step reactions that are going on from glucose, and each of these. So when it has step number one, step number two, all of these, there is an enzyme that is catalyzing this reaction, a specific enzyme, and you'll notice that it has the enzyme name at the bottom. You don't need to know those enzyme things. But I do want to point out to you that most enzymes, their

name ends in ACE. And so I do want you to know that just like when we talked about metabolism or the overall chemical reactions in the cell, most of these are mediated or catalyzed by an individual enzyme. That's what lowers the energy of activation. So the reaction can go forward. OK, we start with glucose, and you'll see that we have a conversion to glucose six-phosphate. What's important is not for you to know those structures or to know the names of those, but to see that the cell is actually making an investment of ATP at this point. Remember, what's the overall goal of cellular respiration? Well, it's to produce ATP for the cell. So this seems counterintuitive that there's an investment of ATP, if that's actually what we're after, but in fact, still has to invest not one, but two molecules of ATP at the beginning of glycolysis. Now, what I want you to see is in step four, so so excuse me back at the beginning,

we need to make sure that we mark or note to ourselves that glucose has six carbons. So we're interested in following each one of these carbons all the way through until they become a carbon of carbon dioxide. So every carbon that we're beginning with in glucose, every one of these will eventually end up as a carbon in carbon dioxide. So we follow it through, we get to step forward and we see that these six carbons of glucose are now broken apart into three carbon compounds. We have two, three carbon compounds, but we still have our six carbons. If we count them up, we still have 6 carbons, we just now have two. It's been separated into two molecules rather than one. OK, and we move on continuing from there, and what I want you to see is here are these two carbon-containing compounds, right? There's three carbons here and there's three carbons here. We still have all six carbons. So this part here that says two times

that means each of these. So this is taking us one of these molecules all the way through till the end of glycolysis. Where we get a pyruvate. Two times means each of these molecules is going to have to go through this process. Right. So we do that times, too, because we're tracking an entire glucose molecule. So we see that overall at the end. For every glucose molecule, we're going to get two molecules of pyruvate. So this is pyruvate at the end, and remember, it only shows one pyruvate because that's tracking from one molecule of one three best bisphospho-glycerate when we know that we have two of those from every molecule of glucose. So do we still have all six carbons? Yes, we do, because pyruvate has three carbons, and we have two of those, so we haven't lost any carbons yet to carbon dioxide. The other thing I want you to see is we

have a production of ATP. So you can see that. The arrow here. What's coming in is ADP, and what we're getting out is ATP in both of these cases, whereas before we were investing ATP. So remember this. This happens twice for every one three bisphospho-glycerate. So if we do the math, we invested two ATP. So we were negative two ATP from the start. But we get two ATP out for every 1-3 bisphosphoglycerate, meaning four total for each glucose. So we're positive two ATP at the end of glycolysis. So in addition to two pyruvate, it's important that we see that we get it, we have a net gain of two ATP. And the other important thing that I want you to see is right here. We have the generation of a molecule that's an electron carrier called NADH, and remember this, it's happening two times. So that means we have two

NADH. Now, these are electron carriers, and these are going to be very important on our last stage when we talk about the electron transport chain. So we're going to keep track of how many of these NADH molecules we're generating as we go through this process. Now, one last thing I want to point out to you is where are the electrons coming from that are being carried by NADH? Well, we've seen that glucose has been broken down, so bonds have been broken, therefore releasing electrons. So these electrons that have been picked up by of these are from glucose.

Glycolysis: Glucose to Pyruvate

Natalie Russell

해당 과정은 세포 호흡의 첫 단계로, 진핵세포와 원핵세포의 세포질에서 일어나며 산소가 필요하지 않습니다.

이 다단계 과정에는 특정 효소가 관여하며, 대부분의 효소 이름은 ACE로 끝나며, 궁극적으로 세포에 필요한 ATP를 생산하기 위해 두 개의 ATP 분자를 초기 투자하는 과정이 포함됩니다.

해당 작용에서 포도당 탄소의 운명

포도당의 6개의 탄소는 해당 과정 중에 최종적으로 두 개의 피루브산 분자로 변환됩니다.

탄소 화합물이 두 분자로 분리되더라도 포도당의 탄소 6개는 모두 피루브산염에 여전히 존재합니다.

이 과정은 해당 과정 중에 원래 포도당의 탄소가 이산화탄소로 손실되지 않음을 보여줍니다.

해당 작용의 ATP 생산 및 순 이득

해당 작용은 각 포도당 분자에 대해 두 개의 ATP를 순증가시킵니다.

ATP 외에도 전자 운반체 분자 NADH도 생성됩니다.

이 과정은 처음에는 두 개의 ATP를 투자하지만 궁극적으로 해당 작용이 끝날 때 양수인 두 개의 ATP로 이어집니다.

전자 수송 사슬에서 NADH의 중요성

NADH는 포도당이 분해되는 과정에서 생성되는 전자 운반체 역할을 하므로 전자 수송 사슬에 매우 중요합니다.

NADH가 운반하는 전자는 포도당 결합의 분해에서 파생됩니다.

전자 수송 사슬의 마지막 단계에서는 NADH 분자의 생성을 추적하는 것이 필수적입니다.