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Respiration may refer to:
Primary nutritional groups are groups of organisms, divided in relation to the nutrition mode according to the sources of energy and carbon, needed for living, growth and reproduction. The sources of energy can be light or chemical compounds; the sources of carbon can be of organic or inorganic origin.
A heterotroph is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but not producers. Living organisms that are heterotrophic include all animals and fungi, some bacteria and protists, and many parasitic plants. The term heterotroph arose in microbiology in 1946 as part of a classification of microorganisms based on their type of nutrition. The term is now used in many fields, such as ecology, in describing the food chain.
Cellular respiration is the process by which biological fuels are broken down in the presence of a hydrogen acceptor, such as oxygen, to drive the production of adenosine triphosphate (ATP), which stores chemical energy in a biologically accessible form. Cellular respiration may be described as a set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from nutrients into ATP, and then release waste products.
In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through chemosynthesis, which uses the oxidation or reduction of inorganic chemical compounds as its source of energy. Almost all life on Earth relies directly or indirectly on primary production. The organisms responsible for primary production are known as primary producers or autotrophs, and form the base of the food chain. In terrestrial ecoregions, these are mainly plants, while in aquatic ecoregions algae predominate in this role. Ecologists distinguish primary production as either net or gross, the former accounting for losses to processes such as cellular respiration, the latter not.
In biochemistry, chemosynthesis is the biological conversion of one or more carbon-containing molecules and nutrients into organic matter using the oxidation of inorganic compounds or ferrous ions as a source of energy, rather than sunlight, as in photosynthesis. Chemoautotrophs, organisms that obtain carbon from carbon dioxide through chemosynthesis, are phylogenetically diverse. Groups that include conspicuous or biogeochemically important taxa include the sulfur-oxidizing Gammaproteobacteria, the Campylobacterota, the Aquificota, the methanogenic archaea, and the neutrophilic iron-oxidizing bacteria.
A biogeochemical cycle, or more generally a cycle of matter, is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is transformed and cycled by living organisms and through various geological forms and reservoirs, including the atmosphere, the soil and the oceans. It can be thought of as the pathway by which a chemical substance cycles the biotic compartment and the abiotic compartments of Earth. The biotic compartment is the biosphere and the abiotic compartments are the atmosphere, lithosphere and hydrosphere.
Dissolved inorganic carbon (DIC) is the sum of the aqueous species of inorganic carbon in a solution. Carbon compounds can be distinguished as either organic or inorganic, and as dissolved or particulate, depending on their composition. Organic carbon forms the backbone of key component of organic compounds such as – proteins, lipids, carbohydrates, and nucleic acids.
Lithotrophs are a diverse group of organisms using an inorganic substrate to obtain reducing equivalents for use in biosynthesis or energy conservation via aerobic or anaerobic respiration. While lithotrophs in the broader sense include photolithotrophs like plants, chemolithotrophs are exclusively microorganisms; no known macrofauna possesses the ability to use inorganic compounds as electron sources. Macrofauna and lithotrophs can form symbiotic relationships, in which case the lithotrophs are called "prokaryotic symbionts". An example of this is chemolithotrophic bacteria in giant tube worms or plastids, which are organelles within plant cells that may have evolved from photolithotrophic cyanobacteria-like organisms. Chemolithotrophs belong to the domains Bacteria and Archaea. The term "lithotroph" was created from the Greek terms 'lithos' (rock) and 'troph' (consumer), meaning "eaters of rock". Many but not all lithoautotrophs are extremophiles.
In biogeochemistry, remineralisation refers to the breakdown or transformation of organic matter into its simplest inorganic forms. These transformations form a crucial link within ecosystems as they are responsible for liberating the energy stored in organic molecules and recycling matter within the system to be reused as nutrients by other organisms.
The respiratory quotient is a dimensionless number used in calculations of basal metabolic rate (BMR) when estimated from carbon dioxide production. It is calculated from the ratio of carbon dioxide produced by the body to oxygen consumed by the body, when the body is in a steady state. Such measurements, like measurements of oxygen uptake, are forms of indirect calorimetry. It is measured using a respirometer. The respiratory quotient value indicates which macronutrients are being metabolized, as different energy pathways are used for fats, carbohydrates, and proteins. If metabolism consists solely of lipids, the respiratory quotient is approximately 0.7, for proteins it is approximately 0.8, and for carbohydrates it is 1.0. Most of the time, however, energy consumption is composed of both fats and carbohydrates. The approximate respiratory quotient of a mixed diet is 0.8. Some of the other factors that may affect the respiratory quotient are energy balance, circulating insulin, and insulin sensitivity.
Microbial metabolism is the means by which a microbe obtains the energy and nutrients it needs to live and reproduce. Microbes use many different types of metabolic strategies and species can often be differentiated from each other based on metabolic characteristics. The specific metabolic properties of a microbe are the major factors in determining that microbe's ecological niche, and often allow for that microbe to be useful in industrial processes or responsible for biogeochemical cycles.
Soil respiration refers to the production of carbon dioxide when soil organisms respire. This includes respiration of plant roots, the rhizosphere, microbes and fauna.
Ecosystem respiration is the sum of all respiration occurring by the living organisms in a specific ecosystem. The two main processes that contribute to ecosystem respiration are photosynthesis and cellular respiration. Photosynthesis uses carbon-dioxide and water, in the presence of sunlight to produce glucose and oxygen whereas cellular respiration uses glucose and oxygen to produce carbon-dioxide, water, and energy. The coordination of inputs and outputs of these two processes creates a completely interconnected system, constituting the underlying functioning of the ecosystems overall respiration.
Maintenance respiration refers to metabolism occurring in an organism that is needed to maintain that organism in a healthy, living state. Maintenance respiration contrasts with growth respiration, which is responsible for the synthesis of new structures in growth, nutrient uptake, nitrogen (N) reduction and phloem loading, whereas maintenance respiration is associated with protein and membrane turnover and maintenance of ion concentrations and gradients.
The carbon cycle is an essential part of life on Earth. About half the dry weight of most living organisms is carbon. It plays an important role in the structure, biochemistry, and nutrition of all living cells. Living biomass holds about 550 gigatons of carbon, most of which is made of terrestrial plants (wood), while some 1,200 gigatons of carbon are stored in the terrestrial biosphere as dead biomass.
Stream metabolism, often referred to as aquatic ecosystem metabolism in both freshwater and marine ecosystems, includes gross primary productivity (GPP) and ecosystem respiration (ER) and can be expressed as net ecosystem production. Analogous to metabolism within an individual organism, stream metabolism represents how energy is created and used (respiration) within an aquatic ecosystem. In heterotrophic ecosystems, GPP:ER is <1 ; in autotrophic ecosystems it is >1. Most streams are heterotrophic. A heterotrophic ecosystem often means that allochthonous inputs of organic matter, such as leaves or debris fuel ecosystem respiration rates, resulting in respiration greater than production within the ecosystem. However, autochthonous pathways also remain important to metabolism in heterotrophic ecosystems. In an autotrophic ecosystem, conversely, primary production exceeds respiration, meaning that ecosystem is producing more organic carbon than it is respiring.
Lake metabolism represents a lake's balance between carbon fixation and biological carbon oxidation. Whole-lake metabolism includes the carbon fixation and oxidation from all organism within the lake, from bacteria to fishes, and is typically estimated by measuring changes in dissolved oxygen or carbon dioxide throughout the day.
Net ecosystem production (NEP) in ecology, limnology, and oceanography, is the difference between gross primary production (GPP) and net ecosystem respiration. Net ecosystem production represents all the carbon produced by plants in water through photosynthesis that does not get respired by animals, other heterotrophs, or the plants themselves.
The 3-Hydroxypropionate/4-hydroxybutyrate cycle, also known as the 3HP/4HB cycle, is a specialized carbon fixation process used by some archaea, including Thermoproteota. For these organisms to survive and grow autotrophically in hostile settings, such as hydrothermal vents, this cycle is essential. Carbon dioxide is effectively transformed by the process into organic chemicals like acetyl-CoA, which can then be utilized for growth and energy production. This route is specific to organisms that fix CO2 in high-temperature, low-oxygen settings, in contrast to the more well-known Calvin cycle which does not perform as well at fixing CO2 under these conditions.
References
- ↑ Wilson, Jesse (2014). "Ocean-Scale Patterns in Community Respiration Rates along Continuous Transects across the Pacific Ocean". PLOS ONE. 9 (7): e99821. Bibcode:2014PLoSO...999821W. doi: 10.1371/journal.pone.0099821 . PMC 4105538 . PMID 25048960.
- ↑ O. Hedin, Lars (1990). "Factors Controlling Sediment Community Respiration in Woodland Stream Ecosystems". Oikos. 57 (1): 94–105. doi:10.2307/3565742. JSTOR 3565742.
- 1 2 Wilson, Jesse (2014). "Ocean-Scale Patterns in Community Respiration Rates along Continuous Transects across the Pacific Ocean". PLOS ONE. 9 (7): e99821. Bibcode:2014PLoSO...999821W. doi: 10.1371/journal.pone.0099821 . PMC 4105538 . PMID 25048960.
- ↑ Gnaiger, Erich; Steinlechner-Maran, Rosmarie; Méndez, Gabriela; Eberl, Thomas; Margreiter, Raimund (1995-12-01). "Control of mitochondrial and cellular respiration by oxygen". Journal of Bioenergetics and Biomembranes. 27 (6): 583–596. doi:10.1007/BF02111656. ISSN 1573-6881. PMID 8746845. S2CID 24142063.
- ↑ Dunn, Jacob; Grider, Michael H. (2023), "Physiology, Adenosine Triphosphate", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 31985968 , retrieved 2023-04-21
- 1 2 3 Wilson, Jesse; Abboud, Sarah; Beman, J. Michael (2017-01-24). "Primary Production, Community Respiration, and Net Community Production along Oxygen and Nutrient Gradients: Environmental Controls and Biogeochemical Feedbacks within and across "Marine Lakes"". Frontiers in Marine Science. 4. doi: 10.3389/fmars.2017.00012 . ISSN 2296-7745.
- ↑ Arístegui, Javier; Montero, María F. (1995). "The relationship between community respiration and ETS activity in the ocean". Journal of Plankton Research. 17 (7): 1563–1571. doi:10.1093/plankt/17.7.1563 . Retrieved 2023-04-21.