Beverley J. Glover
- Published in print:
- 2007
- Published Online:
- January 2008
- ISBN:
- 9780198565970
- eISBN:
- 9780191714009
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198565970.003.0016
- Subject:
- Biology, Plant Sciences and Forestry
The production of coloured tissues, particularly insect-attracting petals, depends upon the synthesis of pigments. Plants are able to mix, modify and enhance pigments to produce a vast array of final ...
More
The production of coloured tissues, particularly insect-attracting petals, depends upon the synthesis of pigments. Plants are able to mix, modify and enhance pigments to produce a vast array of final petal colours. These colours are usually distributed across the flower in patterns, which vary in their degree of regularity and complexity between different species. While colour contrast is much more important than pattern for attracting pollinators from a distance, pattern becomes important at close range and allows animals to distinguish between flowers of different species and to learn to ‘handle’ flowers. This chapter considers the effects of mixing pigments together, the regulation of pigment distribution in the flower, and the use of metals, pH, and cell shape to modify the final colour of the flower.Less
The production of coloured tissues, particularly insect-attracting petals, depends upon the synthesis of pigments. Plants are able to mix, modify and enhance pigments to produce a vast array of final petal colours. These colours are usually distributed across the flower in patterns, which vary in their degree of regularity and complexity between different species. While colour contrast is much more important than pattern for attracting pollinators from a distance, pattern becomes important at close range and allows animals to distinguish between flowers of different species and to learn to ‘handle’ flowers. This chapter considers the effects of mixing pigments together, the regulation of pigment distribution in the flower, and the use of metals, pH, and cell shape to modify the final colour of the flower.
Richard D. Bardgett
- Published in print:
- 2005
- Published Online:
- April 2010
- ISBN:
- 9780198525035
- eISBN:
- 9780191728181
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198525035.003.0001
- Subject:
- Biology, Ecology
Soil forms a thin mantle over the Earth's surface and acts as the interface between the atmosphere and lithosphere, the outermost shell of the Earth. It is a multiphase system, consisting of mineral ...
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Soil forms a thin mantle over the Earth's surface and acts as the interface between the atmosphere and lithosphere, the outermost shell of the Earth. It is a multiphase system, consisting of mineral material, plant roots, water and gases, organic matter at various stages of decay, and a variety of live organisms. The first step towards understanding what controls the abundance and activities of these organisms, and also the factors that lead to spatial and temporal variability in soil biological communities, is to gain an understanding of the physical and chemical nature of the soil matrix in which they live. This chapter provides background on the factors responsible for regulating soil formation, and hence the variety of soils in the landscape. It also discusses the key properties of the soil environment that most influence soil biota, leading to variability in soil biological communities across different spatial and temporal scales.Less
Soil forms a thin mantle over the Earth's surface and acts as the interface between the atmosphere and lithosphere, the outermost shell of the Earth. It is a multiphase system, consisting of mineral material, plant roots, water and gases, organic matter at various stages of decay, and a variety of live organisms. The first step towards understanding what controls the abundance and activities of these organisms, and also the factors that lead to spatial and temporal variability in soil biological communities, is to gain an understanding of the physical and chemical nature of the soil matrix in which they live. This chapter provides background on the factors responsible for regulating soil formation, and hence the variety of soils in the landscape. It also discusses the key properties of the soil environment that most influence soil biota, leading to variability in soil biological communities across different spatial and temporal scales.
Lawrence R. Walker
- Published in print:
- 2011
- Published Online:
- December 2013
- ISBN:
- 9780199575299
- eISBN:
- 9780191774836
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199575299.003.0005
- Subject:
- Biology, Ecology
Disturbances disrupt ecosystem processes, thereby affecting the distribution and abundance of biota. Disturbances alter light and temperature regimes, carbon dioxide and nutrient fluxes, and ...
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Disturbances disrupt ecosystem processes, thereby affecting the distribution and abundance of biota. Disturbances alter light and temperature regimes, carbon dioxide and nutrient fluxes, and productivity. The disturbance of one ecosystem factor is likely to affect most others, as biogeochemical cycles are coupled — to each other and also to landscape and anthropogenic factors. This chapter addresses how organisms respond to alterations of ecosystem processes in the air, soil, and water. Specifically, how do disturbances alter terrestrial light levels, air temperature, carbon dioxide levels, soil nutrients, soil pH, and soil organisms? In aquatic habitats, how do disturbances alter nutrient fluxes, enrichment, and acidification? In addition, transfers of energy and matter across interfaces of aerial, terrestrial, and aqueous parts of an ecosystem are covered. The responses of productivity to disturbance are also examined.Less
Disturbances disrupt ecosystem processes, thereby affecting the distribution and abundance of biota. Disturbances alter light and temperature regimes, carbon dioxide and nutrient fluxes, and productivity. The disturbance of one ecosystem factor is likely to affect most others, as biogeochemical cycles are coupled — to each other and also to landscape and anthropogenic factors. This chapter addresses how organisms respond to alterations of ecosystem processes in the air, soil, and water. Specifically, how do disturbances alter terrestrial light levels, air temperature, carbon dioxide levels, soil nutrients, soil pH, and soil organisms? In aquatic habitats, how do disturbances alter nutrient fluxes, enrichment, and acidification? In addition, transfers of energy and matter across interfaces of aerial, terrestrial, and aqueous parts of an ecosystem are covered. The responses of productivity to disturbance are also examined.
Brian G. Cox
- Published in print:
- 2013
- Published Online:
- May 2013
- ISBN:
- 9780199670512
- eISBN:
- 9780199670512
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199670512.003.0004
- Subject:
- Physics, Condensed Matter Physics / Materials
The determination of dissociation constants in non-aqueous and mixed-aqueous solvents is described. pH-scales, upon which the dissociation constants are based, are defined and compared with the ...
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The determination of dissociation constants in non-aqueous and mixed-aqueous solvents is described. pH-scales, upon which the dissociation constants are based, are defined and compared with the corresponding aqueous scales. Experimental measurements, mostly based on potentiometric titrations using a glass electrode or spectrophotometric measurements of acid-base equilibria, are detailed. Absolute pKa-values are typically anchored to suitable indicator acids, such as picric acid, whose dissociation constants can be conveniently determined by several independent methods. Solute–solute interactions, especially specific association reactions, such as ion-pair and homohydrogen-bond formation, invariably accompany, and often dominate, acid–base equilibria in non-aqueous media. In mixed-aqueous solvents, simultaneous electrode calibration and pKa-determination may be achieved in a single, simple potentiometric titration. The measurement of autoionization constants, which quantify the tendency of a solvent to self-ionize, is also described.Less
The determination of dissociation constants in non-aqueous and mixed-aqueous solvents is described. pH-scales, upon which the dissociation constants are based, are defined and compared with the corresponding aqueous scales. Experimental measurements, mostly based on potentiometric titrations using a glass electrode or spectrophotometric measurements of acid-base equilibria, are detailed. Absolute pKa-values are typically anchored to suitable indicator acids, such as picric acid, whose dissociation constants can be conveniently determined by several independent methods. Solute–solute interactions, especially specific association reactions, such as ion-pair and homohydrogen-bond formation, invariably accompany, and often dominate, acid–base equilibria in non-aqueous media. In mixed-aqueous solvents, simultaneous electrode calibration and pKa-determination may be achieved in a single, simple potentiometric titration. The measurement of autoionization constants, which quantify the tendency of a solvent to self-ionize, is also described.
Christer Brönmark and Lars-Anders Hansson
- Published in print:
- 2017
- Published Online:
- December 2017
- ISBN:
- 9780198713593
- eISBN:
- 9780191781902
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198713593.003.0002
- Subject:
- Biology, Aquatic Biology, Ecology
This chapter draws up the abiotic frame for organisms set by the physical and chemical properties of a specific ecosystem. The abiotic frame is a combination of several features, including wind, ...
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This chapter draws up the abiotic frame for organisms set by the physical and chemical properties of a specific ecosystem. The abiotic frame is a combination of several features, including wind, turbulence, temperature and light, but also by nutrient status, pH and oxygen supply. Based on this abiotic frame, large-scale movements, as well as stratification phenomena of lakes are discussed. The importance of the surrounding land, that is, the catchment area, is stressed; specifically, how the catchment area may strongly affect the physical and chemical features of the lake or pond. In addition, this chapter explains how lakes and ponds have been, and still are, formed in the landscape and how organisms handle the abiotic frame.Less
This chapter draws up the abiotic frame for organisms set by the physical and chemical properties of a specific ecosystem. The abiotic frame is a combination of several features, including wind, turbulence, temperature and light, but also by nutrient status, pH and oxygen supply. Based on this abiotic frame, large-scale movements, as well as stratification phenomena of lakes are discussed. The importance of the surrounding land, that is, the catchment area, is stressed; specifically, how the catchment area may strongly affect the physical and chemical features of the lake or pond. In addition, this chapter explains how lakes and ponds have been, and still are, formed in the landscape and how organisms handle the abiotic frame.
Leonora S. Bittleston
- Published in print:
- 2017
- Published Online:
- February 2018
- ISBN:
- 9780198779841
- eISBN:
- 9780191825873
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198779841.003.0023
- Subject:
- Biology, Plant Sciences and Forestry, Ecology
Carnivorous Nepenthes pitcher plants contain aquatic ecosystems within each fluid-filled pitcher. Communities of arthropods and microbes colonize pitcher pools, and some organisms are endemic to the ...
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Carnivorous Nepenthes pitcher plants contain aquatic ecosystems within each fluid-filled pitcher. Communities of arthropods and microbes colonize pitcher pools, and some organisms are endemic to the pitcher habitat. Flies and mites are the most apparent colonizers, and together with numerous protists, fungi, and bacteria, they form a food web of predators, decomposers, and primary producers. Bacterial diversity and composition are correlated strongly with fluid pH. Closely related organisms co-occur within pitchers, suggesting that competition is not the primary structuring force of pitcher communities. Pitchers are ephemeral habitats when compared with surrounding soil, and the former communities have fewer organisms and are less predictable than the latter. It is still unknown to what extent pitcher plants and their inhabitants influence one another’s fitness.Less
Carnivorous Nepenthes pitcher plants contain aquatic ecosystems within each fluid-filled pitcher. Communities of arthropods and microbes colonize pitcher pools, and some organisms are endemic to the pitcher habitat. Flies and mites are the most apparent colonizers, and together with numerous protists, fungi, and bacteria, they form a food web of predators, decomposers, and primary producers. Bacterial diversity and composition are correlated strongly with fluid pH. Closely related organisms co-occur within pitchers, suggesting that competition is not the primary structuring force of pitcher communities. Pitchers are ephemeral habitats when compared with surrounding soil, and the former communities have fewer organisms and are less predictable than the latter. It is still unknown to what extent pitcher plants and their inhabitants influence one another’s fitness.
Bettina Riedel, Robert Diaz, Rutger Rosenberg, and Michael Stachowitsch
- Published in print:
- 2016
- Published Online:
- May 2016
- ISBN:
- 9780198718826
- eISBN:
- 9780191788352
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198718826.003.0010
- Subject:
- Biology, Aquatic Biology, Ecology
This chapter summarizes the far-reaching consequences and ecological implications of hypoxia and anoxia (low/no oxygen), which have become a global key stressor to marine ecosystems, with over 500 ...
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This chapter summarizes the far-reaching consequences and ecological implications of hypoxia and anoxia (low/no oxygen), which have become a global key stressor to marine ecosystems, with over 500 dead zones recorded worldwide. The focus is on coastal and estuarine ecosystems, which are increasingly at threat due to human impact and climate change. The contribution begins by discussing occurrences of and triggers for oxygen depletions, various definitions, thresholds, and types. It then presents responses to hypoxia/anoxia at various levels, i.e. the individual, population, community, and ecosystem levels. Examples illustrate the cascading effects, direct and indirect, of low dissolved oxygen triggering changes in behaviour, growth, recruitment, species diversity, biological interactions, trophic dynamics, community structure, and habitat complexity, ultimately threatening biodiversity and altering ecosystem structure and function. The chapter closes with a reflection on the interplay and synergy of multiple additional stressors increasingly being studied in combination with hypoxia such as hydrogen sulphide (H2S), higher temperatures, and/or lowered pH.Less
This chapter summarizes the far-reaching consequences and ecological implications of hypoxia and anoxia (low/no oxygen), which have become a global key stressor to marine ecosystems, with over 500 dead zones recorded worldwide. The focus is on coastal and estuarine ecosystems, which are increasingly at threat due to human impact and climate change. The contribution begins by discussing occurrences of and triggers for oxygen depletions, various definitions, thresholds, and types. It then presents responses to hypoxia/anoxia at various levels, i.e. the individual, population, community, and ecosystem levels. Examples illustrate the cascading effects, direct and indirect, of low dissolved oxygen triggering changes in behaviour, growth, recruitment, species diversity, biological interactions, trophic dynamics, community structure, and habitat complexity, ultimately threatening biodiversity and altering ecosystem structure and function. The chapter closes with a reflection on the interplay and synergy of multiple additional stressors increasingly being studied in combination with hypoxia such as hydrogen sulphide (H2S), higher temperatures, and/or lowered pH.
Nic Pacini, Libor Pechar, and David M. Harper
- Published in print:
- 2018
- Published Online:
- February 2019
- ISBN:
- 9780198766384
- eISBN:
- 9780191820908
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198766384.003.0005
- Subject:
- Biology, Aquatic Biology, Biodiversity / Conservation Biology
Chemical equilibria in surface waters stem from complex interactions between physical background and living components of ecosystems. Catchments differ in geological background, climate, and land ...
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Chemical equilibria in surface waters stem from complex interactions between physical background and living components of ecosystems. Catchments differ in geological background, climate, and land use; their run-off bears a distinctive chemical ‘fingerprint’. This chapter illustrates how the monitoring of standard parameters, such as oxygen, pH, conductivity, major ions, nutrients, and carbon, can lead to an interpretation of key aspects of the functioning of major ecosystem processes and how chemical constituents may affect the distribution of aquatic organisms. This requires understanding principles that underlie available measurement techniques and it demands a certain familiarity with the intrinsic variability of parameter values and of their chemical interaction. It is not required that field scientists be able to conduct detailed chemical assessments, but all should be able to collect samples yielding high-quality data. Therefore, detailed advice on chemical monitoring practice is provided, including sample collection, filtering, sample processing, and is discussed with the context of several case studies.Less
Chemical equilibria in surface waters stem from complex interactions between physical background and living components of ecosystems. Catchments differ in geological background, climate, and land use; their run-off bears a distinctive chemical ‘fingerprint’. This chapter illustrates how the monitoring of standard parameters, such as oxygen, pH, conductivity, major ions, nutrients, and carbon, can lead to an interpretation of key aspects of the functioning of major ecosystem processes and how chemical constituents may affect the distribution of aquatic organisms. This requires understanding principles that underlie available measurement techniques and it demands a certain familiarity with the intrinsic variability of parameter values and of their chemical interaction. It is not required that field scientists be able to conduct detailed chemical assessments, but all should be able to collect samples yielding high-quality data. Therefore, detailed advice on chemical monitoring practice is provided, including sample collection, filtering, sample processing, and is discussed with the context of several case studies.
Beverley Glover
- Published in print:
- 2014
- Published Online:
- April 2014
- ISBN:
- 9780199661596
- eISBN:
- 9780191779473
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199661596.003.0017
- Subject:
- Biology, Plant Sciences and Forestry, Ecology
The production of coloured tissues, particularly insect-attracting petals, depends upon the synthesis of pigments. However, very few flowers are coloured simply by the synthesis of one single ...
More
The production of coloured tissues, particularly insect-attracting petals, depends upon the synthesis of pigments. However, very few flowers are coloured simply by the synthesis of one single pigment, and equally few petals are composed of a single block of unchanging colour. Plants are able to mix, modify, and enhance pigments to produce a vast array of final petal colours. These colours are usually distributed across the flower in patterns, which vary in their degree of regularity and complexity between different species. While colour contrast is much more important than pattern for attracting pollinators from a distance, pattern becomes important at close range and allows animals to distinguish between flowers of different species and to learn to ‘handle’ flowers (extract the reward) with the minimum possible expenditure of energy. This chapter considers the effects of mixing pigments together, the regulation of pigment distribution in the flower and the use of metal ions and pH to alter petal colour. It concludes with a discussion of the role of petal surface structure in the production of colour and the modification of pigment colour.Less
The production of coloured tissues, particularly insect-attracting petals, depends upon the synthesis of pigments. However, very few flowers are coloured simply by the synthesis of one single pigment, and equally few petals are composed of a single block of unchanging colour. Plants are able to mix, modify, and enhance pigments to produce a vast array of final petal colours. These colours are usually distributed across the flower in patterns, which vary in their degree of regularity and complexity between different species. While colour contrast is much more important than pattern for attracting pollinators from a distance, pattern becomes important at close range and allows animals to distinguish between flowers of different species and to learn to ‘handle’ flowers (extract the reward) with the minimum possible expenditure of energy. This chapter considers the effects of mixing pigments together, the regulation of pigment distribution in the flower and the use of metal ions and pH to alter petal colour. It concludes with a discussion of the role of petal surface structure in the production of colour and the modification of pigment colour.
Ray Hilborn and Ulrike Hilborn
- Published in print:
- 2019
- Published Online:
- July 2019
- ISBN:
- 9780198839767
- eISBN:
- 9780191875533
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198839767.003.0016
- Subject:
- Biology, Aquatic Biology, Biodiversity / Conservation Biology
Climate Change. The oceans are changing. There is no doubt that the oceans are rapidly getting warmer and more acidic, and this will have significant impacts on fish production. Warmer water causes ...
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Climate Change. The oceans are changing. There is no doubt that the oceans are rapidly getting warmer and more acidic, and this will have significant impacts on fish production. Warmer water causes species to migrate toward polar regions, and increasing acidification will make it more difficult for many species for form shells. It is challenging to make detailed predictions in the face of such unprecedented changes, but the important questions are how, whether, and which species will be able to adapt. The key to management in the face of climate change is the adaptability of our fisheries and fisheries management systems.Less
Climate Change. The oceans are changing. There is no doubt that the oceans are rapidly getting warmer and more acidic, and this will have significant impacts on fish production. Warmer water causes species to migrate toward polar regions, and increasing acidification will make it more difficult for many species for form shells. It is challenging to make detailed predictions in the face of such unprecedented changes, but the important questions are how, whether, and which species will be able to adapt. The key to management in the face of climate change is the adaptability of our fisheries and fisheries management systems.
Brian J. Wilsey
- Published in print:
- 2018
- Published Online:
- August 2018
- ISBN:
- 9780198744511
- eISBN:
- 9780191805738
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198744511.003.0002
- Subject:
- Biology, Plant Sciences and Forestry, Ecology
Grasslands can be surprisingly diverse and contain many charismatic flora and fauna. Plant species are often combined into functional groups. Three major conceptual models: competitors-stress ...
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Grasslands can be surprisingly diverse and contain many charismatic flora and fauna. Plant species are often combined into functional groups. Three major conceptual models: competitors-stress tolerants-ruderals (CSR); the leaf traits, plant height, seed mass (LHS); and R*, used to classify grassland species are described by the author. There are three distinct groups of mammalian herbivores based on the ways that herbivores harbor cellulose degrading microbes: hindgut fermentation, foregut fermentation, and foregut fermentation with rumination. Grasslands have a smaller number of bird species than forested systems, and the bird species that are endemic to grasslands tend to be specialized to open habitat (e.g., large flightless birds). Abundant insects can gathered into feeding groups. Single-celled organisms are important in grassland nutrient cycling and as mutualists and pathogens and are extremely abundant in soil. Soil pH is a strong predictor of bacterial diversity (as in plants), with diversity higher in neutral than in acidic soils.Less
Grasslands can be surprisingly diverse and contain many charismatic flora and fauna. Plant species are often combined into functional groups. Three major conceptual models: competitors-stress tolerants-ruderals (CSR); the leaf traits, plant height, seed mass (LHS); and R*, used to classify grassland species are described by the author. There are three distinct groups of mammalian herbivores based on the ways that herbivores harbor cellulose degrading microbes: hindgut fermentation, foregut fermentation, and foregut fermentation with rumination. Grasslands have a smaller number of bird species than forested systems, and the bird species that are endemic to grasslands tend to be specialized to open habitat (e.g., large flightless birds). Abundant insects can gathered into feeding groups. Single-celled organisms are important in grassland nutrient cycling and as mutualists and pathogens and are extremely abundant in soil. Soil pH is a strong predictor of bacterial diversity (as in plants), with diversity higher in neutral than in acidic soils.
I. David Brown
- Published in print:
- 2016
- Published Online:
- November 2016
- ISBN:
- 9780198742951
- eISBN:
- 9780191802935
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198742951.003.0006
- Subject:
- Physics, Crystallography, Condensed Matter Physics / Materials
The bond valence model applies to the chemistry of liquids as well as solids. Although the bond valence model applies to all liquids (Section 6.6), the properties of aqueous solutions are ...
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The bond valence model applies to the chemistry of liquids as well as solids. Although the bond valence model applies to all liquids (Section 6.6), the properties of aqueous solutions are particularly important. The unique properties of the hydrogen bond determine the chemistry of water (Section 6.2), aqueous solubility (Section 6.2), the hydration spheres around dissolved cations (Section 6.3), protonation of oxyanions (Sections 6.4) and the influence of acidity and alkalinity (pH) on aqueous chemistry (Section 6.5).Less
The bond valence model applies to the chemistry of liquids as well as solids. Although the bond valence model applies to all liquids (Section 6.6), the properties of aqueous solutions are particularly important. The unique properties of the hydrogen bond determine the chemistry of water (Section 6.2), aqueous solubility (Section 6.2), the hydration spheres around dissolved cations (Section 6.3), protonation of oxyanions (Sections 6.4) and the influence of acidity and alkalinity (pH) on aqueous chemistry (Section 6.5).
Dennis Sherwood and Paul Dalby
- Published in print:
- 2018
- Published Online:
- August 2018
- ISBN:
- 9780198782957
- eISBN:
- 9780191826177
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198782957.003.0017
- Subject:
- Physics, Theoretical, Computational, and Statistical Physics
Many reactions in solution involve acids and bases, and so this chapter examines these important reactions in detail. Topics covered include the ionisation of water, pH, pOH, acids and bases, ...
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Many reactions in solution involve acids and bases, and so this chapter examines these important reactions in detail. Topics covered include the ionisation of water, pH, pOH, acids and bases, conjugate acids and conjugate bases, acid and base dissociation constants, the Henderson-Hasselbalch equation, the Henderson-Hasselbalch approximation, buffer solutions and buffer capacity. A unique feature of this chapter is a ‘first principles’ analysis of how a reaction buffered at a particular pH achieves an equilibrium composition different from that of the same reaction taking place in an unbuffered solution. This introduces some concepts which are important in understanding the biochemical standard state, as required for Chapter 23.Less
Many reactions in solution involve acids and bases, and so this chapter examines these important reactions in detail. Topics covered include the ionisation of water, pH, pOH, acids and bases, conjugate acids and conjugate bases, acid and base dissociation constants, the Henderson-Hasselbalch equation, the Henderson-Hasselbalch approximation, buffer solutions and buffer capacity. A unique feature of this chapter is a ‘first principles’ analysis of how a reaction buffered at a particular pH achieves an equilibrium composition different from that of the same reaction taking place in an unbuffered solution. This introduces some concepts which are important in understanding the biochemical standard state, as required for Chapter 23.
Dennis Sherwood and Paul Dalby
- Published in print:
- 2018
- Published Online:
- August 2018
- ISBN:
- 9780198782957
- eISBN:
- 9780191826177
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198782957.003.0023
- Subject:
- Physics, Theoretical, Computational, and Statistical Physics
Applying thermodynamics to biological systems requires the use of the biochemical standard state. Many texts do not mention the biochemical standard state, and most of those that do dismiss it in ...
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Applying thermodynamics to biological systems requires the use of the biochemical standard state. Many texts do not mention the biochemical standard state, and most of those that do dismiss it in three sentences: ‘The equilibrium constant K refers to pH 0. For biological systems, that’s not convenient, and so the biochemical standard state is defined as pH 7. K then becomes K ′. When K ′ replaces K in all the equations, everything works’. This is most unsatisfactory: it is not obvious why K is linked to pH 0, and replacing K by K ′ seems to be a typographical trick. This chapter therefore explains clearly why K relates to pH 0, why this is important, how K ′ relates to the biologically more relevant pH 7, how the biochemical standard is defined and used, and how equations based on conventional standards can be transformed to the biochemical standard.Less
Applying thermodynamics to biological systems requires the use of the biochemical standard state. Many texts do not mention the biochemical standard state, and most of those that do dismiss it in three sentences: ‘The equilibrium constant K refers to pH 0. For biological systems, that’s not convenient, and so the biochemical standard state is defined as pH 7. K then becomes K ′. When K ′ replaces K in all the equations, everything works’. This is most unsatisfactory: it is not obvious why K is linked to pH 0, and replacing K by K ′ seems to be a typographical trick. This chapter therefore explains clearly why K relates to pH 0, why this is important, how K ′ relates to the biologically more relevant pH 7, how the biochemical standard is defined and used, and how equations based on conventional standards can be transformed to the biochemical standard.
