Aerobic Respiration
Aerobic respiration is the process by which cells convert glucose into energy in the presence of oxygen. It involves a series of chemical reactions that occur in the mitochondria, producing a large amount of adenosine triphosphate (ATP) for cellular energy. The overall equation for aerobic respiration is C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.
7 Key excerpts on "Aerobic Respiration"
eBook - ePubBiology
A Self-Teaching Guide
- Steven D. Garber(Author)
- 2020(Publication Date)
- Jossey-Bass(Publisher)
...5 Cellular Respiration Cellular respiration 7777is a series of chemical reactions that frees the energy in fat, protein, and carbohydrate food molecules, rendering it available to the cells (see Figure 5.1). Respiration is generally defined as the oxygen-requiring stage in these biochemical reactions. However, in certain instances, respiration also occurs without any oxygen; this is known as anAerobic Respiration. During respiration, as in photosynthesis (described in Chapter 6), each chemical reaction is catalyzed by an enzyme. To break down glucose molecules, which are the stable end products of photosynthesis, adenosine triphosphate (ATP) is needed to provide the activation energy to initiate the chemical processes that follow. ATP is one of the major energy-providing molecules that initiate biochemical reactions throughout the body. Because ATP, NADH 2, and similar molecules are essential to the maintenance of living systems, organisms need to ensure the constant supply of such energy sources. See Figure 5.2 for the role of enzymes in reducing activation energy, and Figure 5.3 for the role of temperature in enzyme activity. GLYCOLYSIS Each time we eat, our cells break down glucose in our food. The breaking down of glucose involves a process called glycolysis. Glycolysis is the first series of chemical reactions in cellular respiration, in which glucose is converted to pyruvate (pyruvic acid), which is a transport molecule that carries carbon atoms to the mitochondria where oxidation creates molecules that are used for energy, and in the process, carbon dioxide is created. This is why our metabolic processes produce so much carbon dioxide...
eBook - ePub- H. W. Doelle(Author)
- 2014(Publication Date)
- Academic Press(Publisher)
...5 CHEMOSYNTHESIS—Aerobic Respiration Publisher Summary This chapter discusses the aerobic or oxidative respiration that is the enzymatic oxidation of fuel molecules by molecular oxygen. There are only a few bacterial groups that are able to oxidize an inorganic compound for the production of energy: (1) the nitroso group of genera— Nitrosomonas, Nitrosococcus, Nitrosocystis, Nitrosogloea, and Nitrosospira —which oxidize ammonia; (2) the nitro group of genera– Nitrobacter and Nitrocystis– which oxidize nitrite; (3) the genus Hydrogenomonas or hydrogen bacteria (Knallgas bacteria), which oxidize hydrogen; (4) the ferrous iron oxidizing bacteria Ferrobacillus and Thiobacillus ferrooxidans ; (5) the methane-oxidizing bacteria Methanomonas methanooxidans and Pseudomonas methanica ; and (6) the sulfur-oxidizing bacteria Thiobacillus. The chapter also discusses the complete oxidation of pyruvate. The conversion of pyruvate into water and carbon dioxide occurs by means of a series of reactions called the tricarboxylic acid cycle (TCA), Krebs cycle, or citric acid cycle. Enzymes catalyzing the reactions of the TCA cycle have been found in extracts of a wide range of microorganisms. This cycle is the main pathway of oxidative respiration in microorganisms. The operation of this cycle also provides the microorganisms with a number of precursors for biosynthetic reactions. Aerobic Respiration Aerobic or oxidative respiration involves a considerably greater number of processes than in fermentation. It is the enzymatic oxidation of fuel molecules by molecular oxygen. A great number of books and reviews on this subject deal only with the tricarboxylic acid cycle (TCA) as the image of Aerobic Respiration. In microbiology, however, we have a complex group of organisms which are not able to use the TCA cycle, but use molecular oxygen as their final hydrogen acceptor...
eBook - ePubBioprocess Engineering
An Introductory Engineering and Life Science Approach
- Kim Gail Clarke(Author)
- 2013(Publication Date)
- Woodhead Publishing(Publisher)
...The oxygen combines with the electrons and hydrogen ions to form water. The passage of hydrogen and electrons releases energy which is sequestered by the phosphorylation of ADP and Pi and stored as chemical energy in ATP. Sufficient energy is generated by the electron transport chain to form three ATP for each metabolic intermediate oxidised. The energy equation per two hydrogen atoms removed is: 3 ADP + 3 Pi + ½ O 2 3ATP + 4H 2 O. Since energy generation by the electron transport chain is mediated through ADP phosphorylation, this respiration process is also called oxidative phosphorylation, the oxidative phosphorylation chain or respiratory chain oxidation. All aerobic microorganisms undergo Aerobic Respiration and have an obligate requirement for oxygen as the terminal electron acceptor. An oxygen level insufficient to meet the oxygen demand of aerobes results in reduced metabolism. When growth becomes primarily dependent on the oxygen level, a situation known as oxygen limiting, the process yields and productivity decrease accordingly, irrespective of all other conditions being favourable. In the extreme case where oxygen decreases below a critical level, oxidative phosphorylation ceases and the cells lyse. It is for this reason that oxygen transfer to aerobic bioprocesses remains a major criterion for design, operation (Section 8.1) and scale up (Section 9.1). Anaerobic microorganisms, on the other hand, undergo anAerobic Respiration in the absence of exogenous molecular oxygen, using compounds other than oxygen as terminal electron acceptors, e.g. NO 3 −, SO 4 − 2. One of the most important examples of NO 3 − being used as a terminal electron acceptor is in denitrification 3 of waste water, where the NO 3 − accepts electrons and the nitrate nitrogen is reduced to N 2, thereby removing contaminating nitrogenous compounds from the water. Much of energy generation is via oxidative phosphorylation (aerobic or anaerobic)...
- Olen R. Brown(Author)
- 2017(Publication Date)
- Bentham Science Publishers(Publisher)
...Metabolism of cells is conveniently thought of in two categories: catabolism and anabolism. Catabolism refers to processes that break down chemicals to serve as nutrients for cells. Anabolism refers to the processes that create more complex molecules from simpler molecules. Growth, multiplication and repair of cells would not be possible without anabolism, and anabolism requires coupled reaction (subsequently to be described) to provide the necessary energy to create new bonds between atoms and parts of molecules. Catabolism is a complex process involving many stages and many different organelles inside cells. Of interest to us here, is the fact that oxygen serves as the terminal receptors for hydrogen ions and electrons that are derived from chemicals like glucose. To better explain this process it is useful to consider how glucose brings energy into a process that occurs primarily in special organelles called mitochondria (singular mitochondrion). Organelles are intracellular structures that are bounded by membranes and designed for specific functions. With the exception of certain anaerobes, life as we know it on earth cannot exist without oxygen. This derives primarily from the fact that oxygen serves as the terminal acceptor of electrons in a long sequence of reactions whereby energy is transferred and eventually “stored” in adenosine triphosphate (ATP). It is this ATP that serves as the source of energy for life processes. Lawrence Krauss has written about this [ 1 ] 1. Respiration adds oxygen to the process as the terminal receptor of hydrogen ions and electrons removed from intermediates derived from sugar and taken through the cytochromes system where energy gets stored in ATP. It is possible to roughly estimate the amount of oxygen consumed annually by Earth’s human population. Of course, this requires assumptions and the estimate’s accuracy depends on the validity of the assumptions 2. There are data from various sources that differ...
eBook - ePubBack to Basics in Physiology
O2 and CO2 in the Respiratory and Cardiovascular Systems
- Juan Pablo Arroyo, Adam J. Schweickert(Authors)
- 2015(Publication Date)
- Academic Press(Publisher)
...When there is no blood flow, there is no O 2 delivery, and there is no CO 2 removal. Therefore, cells are no longer able to produce energy, and they begin to malfunction. One of the best examples of this is myocardial ischemia—a heart attack. When blood flow to a portion of the heart muscle stops, the heart muscle cells can’t make energy. This causes inflammation and abnormal functioning of these cells. Common clinical manifestations of a myocardial infarction are pain and arrhythmias arising from the infarcted tissue. Figure 1.1 Aerobic cellular respiration is the process through which cells use glucose and oxygen to produce ATP and H 2 O, with CO 2 as a byproduct of the biochemical reactions. Role of Carbon Dioxide (CO 2) The amount of CO 2 that is in the air we breathe is relatively low, but inside the body the amount of CO 2 is much, much higher. As O 2 is actively being consumed during cellular respiration, CO 2 is being produced as a byproduct of the same biochemical pathway (Figure 1.1). Remember: While O 2 is being consumed, CO 2 is being produced. Similar to what happens with O 2, the production of CO 2 by the cell is closely linked to metabolism; the higher the metabolic rate, the more CO 2 produced. The major goal of metabolizing food is to break down the food into its simplest chemical form (usually glucose) and then to remove hydrogen ions and electrons from it. The removal of hydrogen ions and electrons will ultimately power an enzyme called ATP synthase. This enzyme creates ATP, and in doing so creates usable energy. There are many biochemical reactions involving the removal of hydrogen ions and electrons from food, and they differ depending on whether the food is a sugar, a protein, or a fat...
eBook - ePub- Volodymyr Ivanov(Author)
- 2020(Publication Date)
- CRC Press(Publisher)
...22 Anaerobic and Anoxic Biotreatment of Waste Oxygen and Energy Generation The evolution of an anaerobic to an aerobic atmosphere on Earth resulted in the creation of the following: anaerobic (living without oxygen) microorganisms facultative anaerobic (living under either anaerobic or aerobic conditions) microorganisms microaerophilic (living under low concentrations of dissolved oxygen) microorganisms obligate aerobic (living only in the presence of oxygen) microorganisms Anaerobes produce energy from the following: fermentation (destruction of organic substances without an external acceptor of electrons) anAerobic Respiration using electron acceptors such as N O 3 −, N O 2 −, Fe 3+, SO 4 2 −, and CO 2 anoxygenic (H 2 S → S) photosynthesis Microaerophiles and aerobes produce energy from the following: aerobic oxidation of organic matter oxygenic photosynthesis The sequence of increasing the production of biological energy per mole of transferred electrons is as follows: fermentation → CO 2 respiration (“hydrogenotrophic methanogenesis”) → dissimilative sulfate-reduction → dissimilative iron. reduction (“iron respiration”) → nitrate respiration (“denitrification”) → Aerobic Respiration. Anaerobic Digestion of Organic Matter There are many applications of anaerobic processes to the treatment of polluted soil, solid waste, and wastewater...
eBook - ePubBiochemical Pathways
An Atlas of Biochemistry and Molecular Biology
- Gerhard Michal, Dietmar Schomburg, Gerhard Michal, Dietmar Schomburg(Authors)
- 2013(Publication Date)
- Wiley(Publisher)
...Aerobic Respiration and its central role in energy turnover, as well as the photosynthetic reactions that are the source of almost all compounds in living beings, are discussed in Sections 3.11 and 3.12. Many special metabolic reactions take place in plants. These are summarized in Section 3.13. Figure 1.1-1. Biosynthetic Reactions in General Metabolism Key to the background colors: green = carbohydrates; blue = amino acids; red = lipids including steroids; orange = nucleotides; brown = tetrapyrroles; none = compounds involved in general interconversions. The colors of the frames are for easy differentiation only. The biosynthesis of proteins in bacteria and eukarya, and their consecutive modification, as well as the cell cycle, are discussed in Chapter 4. Figure 1.1-2 gives a short outline of these reactions, subdivided into bacterial reactions (left) and eukaryotic reactions (right). Figure 1.1-2 Protein Biosynthesis Viruses, which utilize these mechanisms in hosts, are discussed in Chapter 5. Chapter 6 gives a survey of transport mechanisms through membranes and within vessels. The topic of Chapter 7 is cellular communication and the regulation mechanisms employed by multicellular organisms. Figure 1.1-3 briefly summarizes these multiple interconnections. Figure 1.1-3 Cellular Communication Chapter 8 deals with the defense mechanisms of higher animals and Chapter 9 with blood. coagulation. Every presentation can only contain a selection of the present knowledge. For this reason, the final Chapter 10, is intended to assist in obtaining further information from electronic sources, which offer the most comprehensive collection of scientific results available today. 1.1.1 Conventions Used in This Book 1. A decimal classification system is used throughout with the following subdivisions: chapters, sections, subsections...
