Aerobic respiration

Fermentation is a widespread pathway, but it is not the only way to get energy from fuels anaerobically (in the absence of oxygen). Some living systems instead use an inorganic molecule other than O 2 \text _2 O 2 ​ start text, O, end text, start subscript, 2, end subscript , such as sulfate, as a final electron acceptor for an electron transport chain. This process, called anaerobic cellular respiration, is performed by some bacteria and archaea. Anaerobic cellular respiration is similar to aerobic cellular respiration in that electrons extracted from a fuel molecule are passed through an electron transport chain, driving ATP \text^-) ( NO 3 − ​ ) left parenthesis, start text, N, O, end text, start subscript, 3, end subscript, start superscript, minus, end superscript, right parenthesis , sulfur, or one of a variety of other molecules 1 ^1 1 start superscript, 1, end superscript . What kinds of organisms use anaerobic cellular respiration? Some prokaryotes—bacteria and archaea—that live in low-oxygen environments rely on anaerobic respiration to break down fuels. For example, some archaea called methanogens can use carbon dioxide as a terminal electron acceptor, producing methane as a by-product. Methanogens are found in soil and in the digestive systems of ruminants, a group of animals including cows and sheep. Similarly, sulfate-reducing bacteria and Archaea use sulfate as a terminal electron acceptor, producing hydrogen sulfide ( H 2 S ) (\text H_2\text S) ( H 2 ​ S ) ...

Learning Outcomes • Describe the respiratory chain (electron transport chain) and its role in cellular respiration You have just read about two pathways in cellular respiration—glycolysis and the citric acid cycle—that generate ATP. However, most of the ATP generated during the aerobic catabolism of glucose is not generated directly from these pathways. Rather, it is derived from a process that begins with moving electrons through a series of electron transporters that undergo redox reactions: the electron transport chain. This causes hydrogen ions to accumulate within the matrix space. Therefore, a concentration gradient forms in which hydrogen ions diffuse out of the matrix space by passing through ATP synthase. The current of hydrogen ions powers the catalytic action of ATP synthase, which phosphorylates ADP, producing ATP. Figure 1. The electron transport chain is a series of electron transporters embedded in the inner mitochondrial membrane that shuttles electrons from NADH and FADH 2 to molecular oxygen. In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water. The electron transport chain (Figure 1) is the last component of aerobic respiration and is the only part of glucose metabolism that uses atmospheric oxygen. Oxygen continuously diffuses into plants; in animals, it enters the body through the respiratory system. Electron transport is a series of redox reactions that resemble a relay race o...

Obligate aerobes, facultative anaerobes, and microaerophiles are all types of bacteria that are aerobic because they can use oxygen to make ATP. Some specific examples of bacteria that fall into these categories are Mycobacterium tuberculosis, Pseudomonas aeruginosa, Bacillus subtilis, and Escherichia coli. Respiration describes the process of breathing, while aerobic means oxygen is present in an environment. Many life forms on Earth are categorized as aerobic and undergo respiration. What are aerobic organisms? An aerobic organism is any life form that lives in the presence of oxygen, and in most cases, also requires oxygen to live. Aerobic organisms, or aerobes, are found everywhere in the world where there is oxygen, including the oceans. Aerobic Organisms Think about all life on Earth. Do all the organisms breathe like we do? You might be thinking that they don't. For example, fungus doesn't have lungs with which to breathe. But in actuality, the presence of lungs is not the determining factor here. In fact, fungi do breathe in their own way, because they take in oxygen and use it to create energy to live. And many other organisms that you might not expect breathe in their own ways. Organisms that require oxygen to make energy and to survive are called aerobic organisms, or aerobes. It's important to note that not all organisms are aerobes. Some animals are anaerobic, which means they can create energy without the presence of oxygen, but that's for another lesson. The...

Let’s imagine that you are a cell. You’ve just been given a big, juicy glucose molecule, and you’d like to convert some of the energy in this glucose molecule into a more usable form, one that you can use to power your metabolic reactions. How can you go about this? What’s the best way for you to squeeze as much energy as possible out of that glucose molecule, and to capture this energy in a handy form? Fortunately for us, our cells – and those of other living organisms – are excellent at harvesting energy from glucose and other organic molecules, such as fats and amino acids. Here, we’ll get a high-level overview of how cells break down fuels. Then, we'll take a closer look at some of the electron transfer reactions (redox reactions) that are key to this process. The reactions that extract energy from molecules like glucose are called catabolic reactions. That means they involve breaking a larger molecule into smaller pieces. For example, when glucose is broken down in the presence of oxygen, it’s converted into six carbon dioxide molecules and six water molecules. The overall reaction for this process can be written as: C 6 H 12 O 6 \text C_6\text H_ Δ G = − 6 8 6 kcal/mol delta, G, equals, minus, 686, start text, k, c, a, l, slash, m, o, l, end text In a cell, this overall reaction is broken down into many smaller steps. Energy contained in the bonds of glucose is released in small bursts, and some of it is captured in the form of adenosine triphosphate ( ATP), a small ...

Why subscribe? • The ultimate action-packed science and technology magazine bursting with exciting information about the universe • Subscribe today and save an extra 5% with checkout code 'LOVE5' • Engaging articles, amazing illustrations & exclusive interviews • Issues delivered straight to your door or device You may have heard a strange rumor that turtles can breathe through their butts. But is this true? Technically, turtles do not breathe through their derrières. That's because turtles don't really have "butts"; instead, they have a multipurpose opening known as a cloaca, which is used for sexual reproduction and egg laying as well as for expelling waste. However, they do engage in a process called cloacal respiration, which could, in a less technical sense, be interpreted as "butt breathing." During cloacal respiration, turtles pump water through their cloacal openings and into two sac-like organs known as bursae, which act sort of like aquatic lungs, Craig Franklin, a wildlife physiologist at The University of Queensland in Australia who has extensively studied cloacal respiration, told Live Science. Oxygen in the water then diffuses across the papillae, small structures that line the walls of the bursae, and into the turtle's bloodstream. Related: Why do turtles live so long? However, cloacal respiration is very inefficient compared with normal aerobic respiration ,and all turtles also have the capacity to breathe air with their lungs much more easily. As a result,...

Glycolysis (which is also known as the glycolytic pathway or the Embden-Meyerhof-Parnas pathway) is a sequence of 10 +) is see below). Pyruvate molecules produced during glycolysis then enter the mitochondria, where they are each converted into a compound known as acetyl coenzyme A, which then enters the TCA cycle. (Some sources consider the conversion of pyruvate into acetyl coenzyme A as a distinct step, called pyruvate oxidation or the transition reaction, in the process of cellular respiration.) Tricarboxylic acid cycle The + and flavin adenine dinucleotide (FAD) and converted later to ATP. The products of a single turn of the TCA cycle consist of three NAD + molecules, which are reduced (through the process of adding +) to the same number of NADH molecules, and one FAD molecule, which is similarly reduced to a single FADH 2 molecule. These molecules go on to fuel the third stage of cellular respiration, whereas carbon dioxide, which is also produced by the TCA cycle, is released as a waste product. Oxidative phosphorylation In the 2 provides a pair of

Glycolysis (which is also known as the glycolytic pathway or the Embden-Meyerhof-Parnas pathway) is a sequence of 10 +) is see below). Pyruvate molecules produced during glycolysis then enter the mitochondria, where they are each converted into a compound known as acetyl coenzyme A, which then enters the TCA cycle. (Some sources consider the conversion of pyruvate into acetyl coenzyme A as a distinct step, called pyruvate oxidation or the transition reaction, in the process of cellular respiration.) Tricarboxylic acid cycle The + and flavin adenine dinucleotide (FAD) and converted later to ATP. The products of a single turn of the TCA cycle consist of three NAD + molecules, which are reduced (through the process of adding +) to the same number of NADH molecules, and one FAD molecule, which is similarly reduced to a single FADH 2 molecule. These molecules go on to fuel the third stage of cellular respiration, whereas carbon dioxide, which is also produced by the TCA cycle, is released as a waste product. Oxidative phosphorylation In the 2 provides a pair of

Why subscribe? • The ultimate action-packed science and technology magazine bursting with exciting information about the universe • Subscribe today and save an extra 5% with checkout code 'LOVE5' • Engaging articles, amazing illustrations & exclusive interviews • Issues delivered straight to your door or device You may have heard a strange rumor that turtles can breathe through their butts. But is this true? Technically, turtles do not breathe through their derrières. That's because turtles don't really have "butts"; instead, they have a multipurpose opening known as a cloaca, which is used for sexual reproduction and egg laying as well as for expelling waste. However, they do engage in a process called cloacal respiration, which could, in a less technical sense, be interpreted as "butt breathing." During cloacal respiration, turtles pump water through their cloacal openings and into two sac-like organs known as bursae, which act sort of like aquatic lungs, Craig Franklin, a wildlife physiologist at The University of Queensland in Australia who has extensively studied cloacal respiration, told Live Science. Oxygen in the water then diffuses across the papillae, small structures that line the walls of the bursae, and into the turtle's bloodstream. Related: Why do turtles live so long? However, cloacal respiration is very inefficient compared with normal aerobic respiration ,and all turtles also have the capacity to breathe air with their lungs much more easily. As a result,...

Fermentation is a widespread pathway, but it is not the only way to get energy from fuels anaerobically (in the absence of oxygen). Some living systems instead use an inorganic molecule other than O 2 \text _2 O 2 ​ start text, O, end text, start subscript, 2, end subscript , such as sulfate, as a final electron acceptor for an electron transport chain. This process, called anaerobic cellular respiration, is performed by some bacteria and archaea. Anaerobic cellular respiration is similar to aerobic cellular respiration in that electrons extracted from a fuel molecule are passed through an electron transport chain, driving ATP \text^-) ( NO 3 − ​ ) left parenthesis, start text, N, O, end text, start subscript, 3, end subscript, start superscript, minus, end superscript, right parenthesis , sulfur, or one of a variety of other molecules 1 ^1 1 start superscript, 1, end superscript . What kinds of organisms use anaerobic cellular respiration? Some prokaryotes—bacteria and archaea—that live in low-oxygen environments rely on anaerobic respiration to break down fuels. For example, some archaea called methanogens can use carbon dioxide as a terminal electron acceptor, producing methane as a by-product. Methanogens are found in soil and in the digestive systems of ruminants, a group of animals including cows and sheep. Similarly, sulfate-reducing bacteria and Archaea use sulfate as a terminal electron acceptor, producing hydrogen sulfide ( H 2 S ) (\text H_2\text S) ( H 2 ​ S ) ...

Let’s imagine that you are a cell. You’ve just been given a big, juicy glucose molecule, and you’d like to convert some of the energy in this glucose molecule into a more usable form, one that you can use to power your metabolic reactions. How can you go about this? What’s the best way for you to squeeze as much energy as possible out of that glucose molecule, and to capture this energy in a handy form? Fortunately for us, our cells – and those of other living organisms – are excellent at harvesting energy from glucose and other organic molecules, such as fats and amino acids. Here, we’ll get a high-level overview of how cells break down fuels. Then, we'll take a closer look at some of the electron transfer reactions (redox reactions) that are key to this process. The reactions that extract energy from molecules like glucose are called catabolic reactions. That means they involve breaking a larger molecule into smaller pieces. For example, when glucose is broken down in the presence of oxygen, it’s converted into six carbon dioxide molecules and six water molecules. The overall reaction for this process can be written as: C 6 H 12 O 6 \text C_6\text H_ Δ G = − 6 8 6 kcal/mol delta, G, equals, minus, 686, start text, k, c, a, l, slash, m, o, l, end text In a cell, this overall reaction is broken down into many smaller steps. Energy contained in the bonds of glucose is released in small bursts, and some of it is captured in the form of adenosine triphosphate ( ATP), a small ...