General Biology

Learn the toughest concepts covered in Biology1&2 with step-by-step video tutorials and practice problems by world-class tutors

8. Respiration
1
concept

Glycolysis

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In this video, we're going to introduce Glide, Kalle, ASUs and so Glide Colle. Assis is the very first step of cellular respiration, and it involves the breakdown of a single glucose molecule into two piru of eight molecules. And so when we take a look at the term glide calluses, you'll find these two routes embedded. You'll find the root glencoe and you'll find the root license. And so the root Glick oh, is a route that means sugar. And so glucose is indeed a sugar. And of course, the root license is a route that means to break down. And so when you put these two routes together, Glencoe and license, you get like calluses, which means really breaking down a sugar or breaking down specifically, glucose and glucose is gonna get broken down into two Piru bit molecules. So let's take a look at our image down below here at glide calluses and notice that it starts with a single glucose molecule, and it ends with two Piru V eight molecules, just as we indicated up above. Now it's very important to note that glucose has a total of six carbon atoms, and so notice that down below. We're representing Glucose as these six black circles, and each of these black circles represents one of the carbon atoms found in glucose. Now, glucose does have other types of atoms as well. But when your textbooks and professors are talking about cellular respiration, they mainly tend to focus on the carbon atoms of glucose. And so the glucose here starts with six carbon atoms. And at the end of cellular respiration, I'm sorry. At the end of like Kalle ASUs noticed that the glucose molecule was broken apart into two Piru molecules, each with three carbon atoms. So here we have one pirouette molecule, and here we have a second pirouette molecule. Now it's important to note that as we move forward with Arabic cellular respiration, all six of the carbon atoms that were originally found in glucose are all going to end up being converted to carbon dioxide or CO two. And this is specifically going to happen in the 2nd and 3rd steps of cellular respiration. So this is something to look forward to as we move forward in our course that all of the glucose molecules carbon atoms are all going to eventually end up as carbon dioxide and that carbon dioxide is ultimately gonna end up getting exhaled or breathe out into the environment. Now glide Colle Assis is the Onley step of aerobic cellular respiration that occurs outside of the mitochondria in the cell's cytoplasm. And so this is very important to note, and it's also Glen Collis. This is also the Onley stage of cellular respiration that does not require oxygen, and so that's also a very important key feature to remember about. Like Collis is Glen Collis is can occur in both the presence and the absence of oxygen. And that is not the case with all of the other stages of cellular respiration. So notice down below in our image. Here we have the process of glide. Collis is here in this box, which takes a single glucose molecule with six carbon atoms and breaks it up into two pirouette molecules, each with three carbon atoms, and notice that the process of glide collis iss is occurring on the outside of the mitochondria. So here we have the mitochondria, but like colossus occurs on the outside of the mitochondria, and it's the Onley stage of Arabic cellular respiration that occurs outside of the mitochondria. All of the other stages occur inside of the mitochondria. And once again, like dialysis is the Onley stage that does not require oxygen. Now here, down below. Noticed that were saying that Glen Collis is occurs once again outside mitochondria, specifically in the cells Cytoplasm. So the location of like dialysis is definitely an important feature to remember because like Collis occurs outside of the mitochondria in the cell cytoplasm and all of the other stages occur inside of the mitochondria. Now this here concludes our brief introduction to Glide Collis is and will continue to talk. Maura Maura, about Glen Collis as we move forward here in our course, so I'll see you all in our next video.
2
Problem

Where does the first stage of aerobic cellular respiration take place within a cell?

a) Mitochondrial matrix.

b) Inner mitochondrial membrane.

c) Intermembrane space.

d) Cytoplasm.

3
concept

Phases of Glycolysis

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in this video, we're going to introduce the phases of glycol ASUs. And so it turns out that glide colle assists actually consists of a Siris of a total of 10 chemical reactions and these 10 chemical reactions that make up like Allah assists can actually be grouped into two phases. Now, in this video, we're not really going to focus on the 10 reactions so much. But we are going to focus on how these 10 reactions are grouped into two phases and we're really gonna be focusing on the two phases of like, Collis now. The first phase of Glen Collis is called the Energy Investment Phase and the second phase of Glen Collis. This is called the energy harvest phase. And so notice that the energy investment phase up above is color coordinated to the energy investment phase down below and the energy harvest phases color coordinated to the energy harvest phase down below. And so notice in this image down below. Really, what we're showing you is like Allah assists notice that it's starting with a single glucose molecule that has six carbon atoms, and it breaks down that glucose into two Piru V eight molecules each with three carbon atoms. And so this whole green box represents like Collis is. But once again, like colossus occurs in two phases. The energy investment phase and the energy harvest phase. And so the energy investment phase, as its name implies with the investment, is going to require an investment of energy or an input of energy by using 2 80 p molecules. Now, this is a little bit ironic, because if you recall from our previous lesson videos, the whole point of aerobic cellular respiration is toe make, ah, lot of 80 p. That's the whole point of aerobic cellular respiration to make a lot of 80 p. But the very first stage of Arabic cellular respiration, like Collis, is the very first thing that happens is that it does not make a teepee, but it uses 80 p. That's a little bit ironic, however. It turns out that this is just an investment of the 80 p because, but in putting to a teepee molecules, the cell is able to transition into the second phase of glide calluses, which is the energy harvesting phase. And as its name implies, it's going to harvest energy or produce energy specifically by forming two and A. D H molecules and four ATP molecules. And so, if we take a look at our image down below at Glide, Collis is notice that the first phase of Glide Collis is the energy investment phase is actually going to use to a TPS and that is using some of the cells energy. However, this is just an energy investment because after the cell utilizes those two ATP's, it can transition into the next phase here, which is the energy harvest phase and the energy harvest phase. Notice produces two electron carriers specifically to N a D H molecules, and it also produces a total of four ATP molecules. Now, if we're looking at the Net products from one single glucose molecule, then what we'll see is that not only are two Piru bits formed and two n a. D h r form, but there's also a net of to a teepee molecules that air formed. But wait a second. Jason, I thought you said that there were 4 80 p molecules that were made not to 80 p molecules. Well, what we need to remember is that to a teepee, molecules were being used up in the energy investment phase. So because to a teepee molecules were used up Of the four ATP molecules that are being made, two of them are just making up for the two that were invested. And so really, there's just a net of 28 p molecules made. And so notice if we take a look at this part of our image down below right here, we're reminding you that the energy harvesting phase does produce a total of four ATP's, as we indicated right here, However, we can't forget that the energy investment phase burns or uses to ATP. So we have to subtract off those two ATP's from the total. And so that gives us a total net of two ATP molecules produced during like dialysis to Net ATP's made and so uneasy way to be able to remember that there's 2 80 p maids during like Allah assists is to remember that the Net products from one glucose molecule are just double. You get not only to Piru Bates, but also to and a th, and also to net a teepee molecules. Now, these two Piru bits that are end up forming at the end of July. Collis ISS They end up getting transported to the mitochondrial matrix, basically getting transported to the mitochondria so that the next step of cellular respiration could take place. And so notice that here glide, Collis occurs once again on the outside of the mitochondria, and it ends up producing two and a d. H. A net of to a. T. P s and two Piru Bates. And so these two Piru Bates are going to make their way to the mitochondria and into the mitochondrial matrix. And so this here concludes, our introduction to the phases of Glide Collis is and will be able to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video.
4
concept

Remembering Phases of Glycolysis

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in this video, what we have is a silly memory tool for helping you with remembering the phases of glycol icis. And so when it comes to the phases of glycol icis, you can remember that Gary invests to harvest his profits and travel to Mexico. And so if you can remember that Gary invest to harvest his profits and travel to Mexico then hopefully that can help you remember these phases of like policies. And so the G. And Gary here can help you remember that the process of glycolic starts with a glucose molecule which has six carbons represented by these six black circles that you see here and then the eye and invests is going to stand for the I. In the investment phase which is the very first phase of like hollis is where the cell needs to invest to a tee pee molecules in order to get the process of glycolic. This started then the H. And harvest is going to stand for the H. And the harvest phase of glycol assist, which is the second phase of glycol assist where the cell can double the amount of energy that it invested. And so it's able to produce 4 80 P. S. And a total net of 2 80 P. S. Since It had to invest two ATPs to begin with, then the P. And profits is going to stand for the P. And piru bait because this is ultimately what the process of glycol icis ends with the formation of 23 carbon piru bait molecules. So you can see those 23 carbon piru baits highlighted here and then once these piru baits have been formed, the process of glycol ISIS is over. So you can see here that the process of glycol Asus is indicated by this green box. And what needs to happen is these two piru baits that were formed. They need to travel to the mitochondria. And so that is where this Mexico comes into place. So traveling to Mexico represents traveling the piru bates traveling to the mitochondria. And so that is where the second uh stage of cellular respiration will take place. And so notice here what we have in this image is a mitochondria that is chilling on the beach in Mexico, sipping on some pina coladas or something like that. And so hopefully uh this little memory tool here Gary invest to harvest his profits and travel to Mexico can help you with remembering the phases of like dialysis. And so that being said, we'll be able to apply some of these concepts moving forward. So I'll see you all in our next video
5
example

Glycolysis Example 1

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So here we have an example problem that wants us to fill in the blank here, using one of these five potential answer options down below And the example problem says there is an energy investment step needed to get Glen Collis has started requiring the use of Blank a TPS. And once again, we've got these five potential answer options down below. And so what we need to recall is that Glen Collis is has two phases the energy investment phase and the energy harvest phase. The energy investment phase requires an investment of 2. 80 p s. And so really, that's what this example problem is getting at an order for the energy investment step to occur, it requires the use of 2. 80 p s. And so the correct answer here is going to be answer option A. Now, after the 2 80 p s have been used, then the cell can transition to the second phase of Glen Collis is which is the energy harvest phase. And the energy harvest phase produces a total of 4 80 p s and two and a. D h. And of those 4. 80 p s because two of them got burnt. Ultimately, it's on Lee, a net of two ATP's that are made. But once again, in terms of the energy that needs to be invested, it's to a TPS that need to be invested. So the correct answer to this example is answer. Option A. And that concludes this example. So I'll see you all in our next video.
6
Problem

Starting with one molecule of glucose, glycolysis results in the net production of which of the following sets of energy-containing products?

a) 2 NAD+, 2 pyruvate, and 2 ATP.

b) 2 NADH, 2 pyruvate, and 2 ATP.

c) 4 NADH, 2 pyruvate, and 4 ATP.

d) 6 CO2, 2 pyruvate, and 2 ATP.

7
Problem

Which of the following is a result of glycolysis?

a) A net gain of four ATP per one glucose molecule.

b) Conversion of FAD to FADH2.

c) Conversion of one glucose molecule to two pyruvate molecules.

d) Conversion of NADH to NAD+.

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