Biological Sciences
Bioenergetics
Bioenergetics is the study of how living organisms acquire and utilize energy. It focuses on the processes of energy transformation within cells, including the production and consumption of adenosine triphosphate (ATP), the primary energy currency of cells. Understanding bioenergetics is crucial for comprehending various biological processes, such as metabolism, growth, and reproduction.
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11 Key excerpts on "Bioenergetics"
eBook - PDF- Harold Morowitz(Author)
- 2012(Publication Date)
- Academic Press(Publisher)
We are thus able to make contact between thermodynamics and the study of energy flow in ecology. So far we have dealt with rather general considerations of radiant and chemical energy. Other terms in the internal energy such as charge transfer, surface energy, and osmotic work are of major importance in biology. In the next chapter we present some approaches used to deal with these topics. BILIOGRAPHY Krebs, H. A., and Kornberg, H. L., Energy Transformations in Living Matter. Springer, New York, 1957. A detailed review of the relation of intermediary metabolism to Bioenergetics. Lehninger, A. L., Biochemistry. Worth Publ., New York, 1975. This very extensive textbook of biochemistry details the metabolic pathways involved in bio-energetics and discusses various aspects of the subject. Morowitz, H. J., Energy Flow in Biology, Academic Press, New York, 1968. Much of this chapter comes from Chapter IV of this work. Slobodkin, L. B., Growth and Regulation of Animal Populations. Holt, New York, 1961. Chapter 12 discusses the efficiency of predator-prey energy conversions. Watt, B. K., and Merrill, A. L., Composition of Foods. U.S. Dept. of Agriculture, Washington, D.C., 1963. Contains extensive data on heats of combustion of a wide variety of biological materials.
eBook - ePubBiomolecules
From Genes to Proteins
- Shikha Kaushik, Anju Singh(Authors)
- 2023(Publication Date)
- De Gruyter(Publisher)
Chapter 4 Concept of Energy in BiosystemsThe highly structured and organized nature of living systems is perceptible and astonishing. Growth, development, and metabolism are some of the fundamental processes that occur in living organisms, and the role of energy is fundamental to all these biological processes. The survival of any living organism depends on energy transformations, that is, the exchange of energy within and without a particular system. The fundamental matter in Bioenergetics, that is, the study of energy relationships and conversions in living organisms, signifies the way by which energy from fuel metabolism or by capturing light is coupled to the energy-requiring reactions occurring in the cell. Muscular contraction, synthetic reactions, and active transport are some of the important processes that get energy when linked or coupled with some energy-releasing reactions (exergonic reactions). In all organisms (autotrophic and heterotrophic), ATP (adenosine triphosphate) plays an important role in transferring energy from the exergonic to the endergonic reactions. ATP is called a high-energy phosphate compound and is produced by living organisms via oxidative phosphorylation. The terminal phosphate linkage in ATP is relatively weak; when broken, it yields adenosine monophosphate (AMP) and inorganic phosphate and releases a large amount of energy. An organism’s stockpile of ATP is used by the cells to perform different activities to sustain life, and energy released from rearrangement of bonds within molecules is utilized to power all biological processes in every organism.Bioenergetics or biochemical thermodynamics deals with the transformations, exchange, requirements, and processing of energy within living systems. It also focuses on how cells transfer energy. Some of the essential biological processes such as biosynthesis of nucleic acids and other biomolecules are not thermodynamically favored under provided conditions, as they require an input of energy. They can proceed if coupled with energy-releasing processes. So, it endows with the answer why some reactions may occur while others do not.
eBook - PDF- Gerald Karp, Janet Iwasa, Wallace Marshall(Authors)
- 2021(Publication Date)
- Wiley(Publisher)
CHAPTER OUTLINE 3.1 Bioenergetics 3.2 Enzymes as Biological Catalysts The Human Perspective: The Growing Problem of Antibiotic Resistance 3.3 Metabolism The Human Perspective: Caloric Restriction and Longevity 3.4 Green Cells: Regulation of Metabolism by the Light/Dark Cycle 3.5 Engineering Linkage: Using Metabolism to Image Tumors 100 CHAPTER 3 Bioenergetics, Enzymes, and Metabolism 3.1 Bioenergetics A living cell bustles with activity. Macromolecules of all types are assembled from raw materials, waste products are pro- duced and excreted, genetic instructions flow from the nucleus to the cytoplasm, vesicles are moved along the secretory path- way, ions are pumped across cell membranes, and so forth. To maintain such a high level of activity, a cell must acquire and expend energy. The study of the various types of energy transformations that occur in living organisms is referred to as Bioenergetics. The Laws of Thermodynamics Energy is defined as the capacity to do work, that is, the capac- ity to change or move something. Thermodynamics is the study of the changes in energy that accompany events in the universe. The following sections focus on a set of concepts that allow us to predict the direction that events will take and whether an input of energy is required to cause the event to happen. However, thermodynamic measurements provide no help in determining how rapidly a specific process will occur or the mechanism used by the cell to carry out the process. The First Law of Thermodynamics The first law of thermodynamics is the law of conservation of energy. It states that energy can neither be created nor destroyed. Energy can, however, be converted (transduced) from one form to another. The transduction of mechanical energy to electrical energy occurs in the large wind-turbines now being used to generate energy from wind (Figure 3.1a), and chemical energy is converted to electrical energy by gas-powered generators.
eBook - PDF- John Wrigglesworth(Author)
- 1997(Publication Date)
- CRC Press(Publisher)
1 Introduction to Bioenergetics Two CONDITIO NS NECESSARY FOR LIFE • Mechanism(s) for the control of energy flow • Systems for informa-tion storage and transmiss ion 1.1 Life and ener gy Energy flow is essential for life and Bioenergetics describes how living systems capture, transform and use energy. Almost immediately we meet a problem which turns most students away from the subject. The concept of energy is not an easy one. Definitions are very abstrac t, 'the capa city to do work', 'the energy of an object by virtue of its position', the 'rest-mass energy' of an object. In fact we real ly have no knowledg e of what energy is. Another awkward fact is tha t energy also seems to exist in many different forms. We can speak of potential energy, kinetic energy, heat energy, elec-trical energy, chemical energy, radiant energy, nuclear energy, and ev en 'information ' en ergy. Certain observational facts or laws, the laws of thermodynamics, allow us to do various calculations about energy and energy transforma-tions but these do not lead us any closer to the abstract thing tha t is called energy. Nevertheless, the conti nuous flow of energy through organisms is required for life. A second requirement for life, which is probably easier to imagine, is some method of storing information and passing the knowledge from one generation to the next. We know how this works quite well. The information is stored in the linear sequence of bases in deoxyribonucleic acid (DNA) in the form of the genetic code. Replication of DNA occurs to transmit the informatio n from one generation to the next. The production of ribonucleic acid (RNA) (transcription) and protein (translatio n) allows this informatio n to be used for the essential functions of life. Nevertheless, althoug h an information system is necessary for life it is not sufficient on its own. For example, we do not think of viruses as living systems although they have a very efficient informatio n sto-rage system.
eBook - PDF- Ronald W. Hardy(Author)
- 2002(Publication Date)
- Academic Press(Publisher)
1. Bioenergetics 5 The Fire of Life , two books, discussing several aspects of energy metabolism of animals, that remain very influential to this day. Ege and Krogh (1914) were the first to apply the principles of bioener-getics to fish. Ivlev (1939) worked with carp. Since then, there have been several hundred reports on studies of energy utilization and expenditure for several species of fish. Many reviews have also been made on fish bioenerget-ics, including those by Phillips (1972), Brett and Groves (1979), Cho et al. (1982), Elliott (1982), Cho and Kaushik (1985), Tytler and Calow (1985), Smith (1989), Cho and Kaushik (1990), Kaushik and M´ edale (1994), Cho and Bureau (1995), and M´ edale and Guillaume (1999), which are most relevant to aquaculture. 1.3 Energy Exchange in Biological Systems The first law of thermodynamics, also known as the law of conservation of energy, states that the total energy ( E ) of a system, including its sur-roundings, remains constant unless there is input of energy (heat or work). It implies that within the total system, energy is neither lost nor gained during any changes. However, within that total system, energy may be trans-ferred from one part to another or may be transformed into another form of energy (heat, electrical energy, radiant energy, or mechanical energy). Thermodynamic principles as they apply to biological systems are reviewed in several textbooks (e.g., Patton, 1965; Blaxter, 1989; Mayes, 2000). Readers are invited to refer to these for a more comprehensive presentation of these principles. All biological organisms must obtain supplies of free energy from their environment to sustain living processes. Nonbiological systems may utilize heat energy to perform work, but biological systems are essentially isother-mic and use chemical energy to sustain life processes.
eBook - PDF- H W Doelle(Author)
- 1994(Publication Date)
- WSPC(Publisher)
CHAPTER 6 C e l l T h e r m o d y n a m i c s 1. Concept of thermodynamics of biological systems One of the most fundamental properties of l i v i n g c e l l systems is their a b i l i t y to u t i l i z e and transform energy. This energy occurs in a number of forms: Mechanical Energy is developed during cellular movement, beating of flagella, reorganization of intracellular structures such as mitochondria, and alteration of c e l l shape; Electrical Energy is produced when electrons move from one place to another, usually expressed as a flow of current between two points due to a difference in voltage; Electromagnetic Energy occurs in the form of radiation, and in biology the most significant is that from visible or near-visible light, such as radiation from the sun for photosynthet-ic organisms. Some organisms release energy and glow, which i s referred to as bioluminescence. They produce light energy. Chemical Energy is the energy that can be released from chemical reactions; Thermal Energy or heat is produced as part of the normal energy transformation processes and occurs as waste energy released into the surroundings; Atomic Energy i s contained within the structure of atoms themselves and is released in the form of atomic radiation, which can not be u t i l i z e d by living organisms. Since growth can be defined as the orderly increase of a l l chemical components, i t is the chemical form of energy which is of greatest importance for the understanding of microbial growth and metabolism. Microbial metabolism consists of thousands of individual chemical and enzyme-catalyzed chemical reactions. These chemical reactions in l i v i n g organisms occur in characteristi-cally organized sequences, called metabolic pathways. There are two main types of metabolic pathways: (a) pathways which lead from large (low oxidative state) to smaller molecules (high oxidative state), which are called catabolic pathways or catabolism. 91
eBook - PDFKarp's Cell and Molecular Biology
Concepts and Experiments
- Gerald Karp, Janet Iwasa, Wallace Marshall(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
If you eat corn every day, you don’t turn into a corn plant. How is the chemical composition of our bodies held constant when our intake of food can be so variable? Again the answer lies in the network of biochemical reactions, orchestrated by enzymes that can convert one type of biochemical into another. We aren’t what we eat: We are what our enzymes make us. Bioenergetics, Enzymes, and Metabolism Painting by Giuseppe Arcimboldo: Rudolf II of Habsburg as Vertumnus. SOURCE: Painting by GiuseppeArcimboldo 81 CHAPTER 3 Bioenergetics, Enzymes, and Metabolism 82 3.1 The Laws of Thermodynamics A living cell bustles with activity. Macromolecules of all types are assembled from raw materials, waste products are produced and excreted, genetic instructions flow from the nucleus to the cyto- plasm, vesicles are moved along the secretory pathway, ions are pumped across cell membranes, and so forth. To maintain such a high level of activity, a cell must acquire and expend energy. The study of the various types of energy transformations that occur in living organisms is referred to as Bioenergetics. Energy is defined as the capacity to do work, that is, the capac- ity to change or move something. Thermodynamics is the study of the changes in energy that accompany events in the universe. In the following sections, we will focus on a set of concepts that allow us to predict the direction that events will take and whether an input of energy is required to cause the event to happen. However, thermo- dynamic measurements provide no help in determining how rapidly a specific process will occur or the mechanism used by the cell to carry out the process. The First Law of Thermodynamics The first law of thermodynamics is the law of conservation of energy. It states that energy can neither be created nor destroyed. Energy can, however, be converted ( transduced) from one form to another.
eBook - PDF- E. Broda(Author)
- 2014(Publication Date)
- Pergamon(Publisher)
The fundamental conservatism in the cellular Bioenergetics of higher organisms is clearly due to the perfection that had been reached before differentiation began. But modifications in detail have probably been going on all along in respect to fermentation (as mentioned), to oxidative and to photophosphorylation. Increasingly, the powerful methods of modern biochemistry allow resolution of the differences in structure and function of the organelles for energy production between groups of higher organisms. But only rarely these differences can be correlated with the needs as they arise in the specific ways of life of the particular groups. Nevertheless, the analysis and comparison of the organelles, as found in the diff-erent groups, provide us with a fine additional tool for the construction of phylogenetic trees. The eobionts and the organisms (cells) had to show their efficiency largely in the struggle for energy. They developed methods to get as much ATP as possible, first from the chemical energy of preformed organic substances, later by photosynthesis, and finally by the utiliza-tion of the products of photosynthesis in respiration. Higher organisms have concentrated on the methods for the efficient application of biochemical energy, admittedly often in the pursuit of more energy. The more the division of labour was developed, the more important became intercellular and interorganismal communication and control. Hence for an understanding of more and more complicated systems, thermodynamics and kinetics must increasingly be supplemented by cybernetics, by applied systems analysis. Hormonal or neural mechanisms may be employed. The present book is mainly devoted to cellular Bioenergetics. Therefore it is not intended to deal inextenso with the effects of the division of labour within differentiated organisms THE EVOLUTION OF THE BIOENERGETIC PROCESSES on the localization and intensity of the energy supply processes among cells and tissues.
eBook - PDFBiothermodynamics
Principles and Applications
- Mustafa Ozilgen, Esra Sorguven Oner(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
Understanding the thermodynamic aspects of the energy metabolism would enable us to gain insight on how living organisms are functioning. Questions concerning the health state of a cell, aging, and emergence of cellular diseases may be answered by understanding how the energy, entropy, and exergy of metabolites are manipulated by intracellular reactions. In order to perform a thermodynamic analysis, first, we need to define our system precisely. Here, we will explain the thermodynamic analysis of the energy metabolism based on the model cell proposed by Genç et al. (2013a,b). This model cell is in contact Glycolytic pathway Artery Vein TCA cycle and electron transport chain H 2 O CO 2 O 2 Glucose ADP H 2 O Pl ATP sink Cytoplasm ACoA PYR OAA MAL SUC SCoA ATP NAD CIT αKG ADP NADH ADP ATP ADP ATP Pl NADH NAD ADP ADP ATP ATP G6P Glucose F168P GAP 1,38PG 3PG 2PG PEP H 2 O PYR F6P Mitochondrion Pl H 2 O O 2 ATP FIGURE 4.4 Schematic description of the cellular energy metabolism model. 193 Thermodynamic Aspects of Biological Processes with the extracellular fluid as shown in Figure 4.5. The overall system model cell is divided into six subsystems: 1. Mitochondrion: Here, pyruvate is degraded via the citric acid cycle and the ETC to produce ATP, that is, reactions listed in Table 4.2 are occurring here. Mitochondrial fluid is assumed to be an ideal solution with uniform T m , p m , and c i,m . 2. Mitochondrial membrane (T1): One boundary of this system is inside the cyto- plasm, and the other is inside the mitochondrion (Figure 4.5). No reactions occur here. The system T1 transfers the reactants of the mitochondrial reactions from cytoplasm to mitochondrion and the products from mitochondrion to cytoplasm. The system has uniform temperature and pressure. The concentrations of the metabolites vary linearly between the two boundaries. 3. Cytoplasm: Reactions listed in Table 4.3 occur here.
- Efstathios Michaelides(Author)
- 2021(Publication Date)
- Cambridge University Press(Publisher)
The chemical energy is the defining component of the exergy of the several molecules that participate in these processes. Using the data in Table 2.2 for fuels and the state of technology of semipermeable membranes for mechanical power production, it was stipulated in Eq. (2.32) that the exergy change associated with industrial fuel reactions in the terrestrial environment is approximated with the Gibbs’ free energy, ΔG 0 . This approximation does not apply to the biochemical reactions, because they occur in living cells and the membranes of the cells are functional semi-permeable membranes, through which the biochemical mol- ecules diffuse. For biological systems the “environment,” where the biochemical reac- tions occur, is not the terrestrial atmosphere but the animal cells that have different constituents and entirely different composition. Consequently, it is the chemical com- position of the biological cells – and not that of the atmosphere – that must come in the calculations of the biological exergy. An example of such calculations is the exergy associated with the ATP hydrolysis reaction, which generates the energy for the animal body tissue: ATP ! ADP þ Phosphate or C 10 H 15 N 5 O 3 OH ð Þ PO 3 ð Þ 3 ! C 10 H 15 N 5 O 3 OH ð Þ PO 3 ð Þ 2 þ PO 3 : (5.11) This is one of the essential biochemical reactions that follows the reduction of food nutrients and facilitates the production of mechanical energy in animals and humans. The energetic and exergetic result of the metabolic biochemical processes is the breakdown and oxidation of glucose and fats to produce ATP. The ATP is then hydrolyzed, as in Eq. (5.11), and delivers energy and exergy to the tissues of the human body, including the skeletal muscles.
eBook - PDFBioenergetics at a Glance
An Illustrated Introduction
- D. A. Harris(Author)
- 2009(Publication Date)
- Wiley-Blackwell(Publisher)
The identification of non-equilibrium (potentially energy dissipating) reactions in the cell is another feature of the discipline of Bioenergetics. Thermodynamic principles. therefore, are quite consistent with the maintenance of living systems-although they do set certain con- straints on the models we can use. The appearance of life, or its evolution from simple chemicals, is more problematic. Luckily for us, the process is at least feasible. Clearly, energy is needed to drive unfavourable reactions-for example, sunlight evaporating a rock pool could drive a dehydration. The other, less obvious, factor is again a kinetic one. This new compound needs to be stable enough to remain, even after the tide has come back in, to take part in another energy requiring process, and another, and so on by chance until it becomes able to harvest energy and replicate itself. The problem here is one of time-for how long does the compound need to be stable, what is the chance of the next combination, etc. In thermodynamic terms, evolution moves through a series of increasingly unlikely-but kinetically stable-steady states. Evolu- tion oflife is feasible but improbable; how improbable we can decide only when a statistically significant number of inhabited and unin- habited planets is available for study! \ \ I I / '\ \ ,. \ I I / / < ......... . ---' la) (b) (e) (d) 11 III Energy, entropy and the living cell d: horizontal distance i 0. i . . j . . f i I J::: A (a) Entropy and chemica' reactions Chemical processes proceed with breakage and re-formation of chemical bonds--and thus energy and entropy will alter during these changes. The second law of thermodynamics--designating the direction of change-tells us that: 1 A + B will tend to change into C so long as there is a net increase in the entropy of the universe. 2 A mixture of A, Band C will reach equilibrium when the entropy of the universe is maximized, i.e.
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