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Thermogenesis
Thermogenesis is the process of heat production in organisms. It occurs in all warm-blooded animals, and also in a few species of thermogenic plants such as the Eastern skunk cabbage, the Voodoo lily ('' Sauromatum venosum''), and the giant water lilies of the genus '' Victoria''. The lodgepole pine dwarf mistletoe, '' Arceuthobium americanum'', disperses its seeds explosively through thermogenesis.Rolena A.J. deBruyn, Mark Paetkau, Kelly A. Ross, David V. Godfrey & Cynthia Ross Friedman (2015)"Thermogenesis-triggered seed dispersal in dwarf mistletoe" Types Depending on whether or not they are initiated through locomotion and intentional movement of the muscles, thermogenic processes can be classified as one of the following: * Exercise-associated thermogenesis (EAT) * Non-exercise activity thermogenesis (NEAT), energy expended for everything that is not sleeping, eating or sports-like exercise. * Diet-induced thermogenesis (DIT) Shivering One method to raise temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermic Effect Of Food
Specific dynamic action (SDA), also known as thermic effect of food (TEF) or dietary induced thermogenesis (DIT), is the amount of energy expenditure above the basal metabolic rate due to the cost of processing food for use and storage. Heat production by brown adipose tissue which is activated after consumption of a meal is an additional component of dietary induced thermogenesis. The thermic effect of food is one of the components of metabolism along with resting metabolic rate and the exercise component. A commonly used estimate of the thermic effect of food is about 10% of one's caloric intake, though the effect varies substantially for different food components. For example, dietary fat is very easy to process and has very little thermic effect, while protein is hard to process and has a much larger thermic effect.Christensen, Peter"What is the thermic effect of food?" Retrieved March 28, 2005. Factors that affect the thermic effect of food The thermic effect of food is in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermogenin
Thermogenin (called uncoupling protein by its discoverers and now known as uncoupling protein 1, or UCP1) is a mitochondrial carrier protein found in brown adipose tissue (BAT). It is used to generate heat by non-shivering thermogenesis, and makes a quantitatively important contribution to countering heat loss in babies which would otherwise occur due to their high surface area-volume ratio. Mechanism UCP1 belongs to the UCP family which are transmembrane proteins that decrease the proton gradient generated in oxidative phosphorylation. They do this by increasing the permeability of the inner mitochondrial membrane, allowing protons that have been pumped into the intermembrane space to return to the mitochondrial matrix. UCP1-mediated heat generation in brown fat uncouples the respiratory chain, allowing for fast substrate oxidation with a low rate of ATP production. UCP1 is related to other mitochondrial metabolite transporters such as the adenine nucleotide translocator, a pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uncoupling Protein
An uncoupling protein (UCP) is a mitochondrial inner membrane protein that is a regulated proton channel or transporter. An uncoupling protein is thus capable of dissipating the proton gradient generated by NADH-powered pumping of protons from the mitochondrial matrix to the mitochondrial intermembrane space. The energy lost in dissipating the proton gradient via UCPs is not used to do biochemical work. Instead, heat is generated. This is what links UCP to thermogenesis. However, not every type of UCPs are related to thermogenesis. Although UCP2 and UCP3 are closely related to UCP1, UCP2 and UCP3 do not affect thermoregulatory abilities of vertebrates. UCPs are positioned in the same membrane as the ATP synthase, which is also a proton channel. The two proteins thus work in parallel with one generating heat and the other generating ATP from ADP and inorganic phosphate, the last step in oxidative phosphorylation. Mitochondria respiration is coupled to ATP synthesis (ADP phosphorylat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Adipose Tissue
Brown adipose tissue (BAT) or brown fat makes up the adipose organ together with white adipose tissue (or white fat). Brown adipose tissue is found in almost all mammals. Classification of brown fat refers to two distinct cell populations with similar functions. The first shares a common embryological origin with muscle cells, found in larger "classic" deposits. The second develops from white adipocytes that are stimulated by the sympathetic nervous system. These adipocytes are found interspersed in white adipose tissue and are also named 'beige' or 'brite' (for "brown in white"). Brown adipose tissue is especially abundant in newborns and in hibernating mammals. It is also present and metabolically active in adult humans, but its prevalence decreases as humans age. Its primary function is thermoregulation. In addition to heat produced by shivering muscle, brown adipose tissue produces heat by non-shivering thermogenesis. The therapeutic targeting of brown fat for the treatment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermogenic Plants
Thermogenic plants have the ability to raise their temperature above that of the surrounding air. Heat is generated in the mitochondria, as a secondary process of cellular respiration called thermogenesis. Alternative oxidase and uncoupling proteins similar to those found in mammals enable the process, which is still poorly understood. The role of thermogenesis Botanists are not completely sure why thermogenic plants generate large amounts of excess heat, but most agree that it has something to do with increasing pollination rates. The most widely accepted theory states that the endogenous heat helps in spreading chemicals that attract pollinators to the plant. For example, the Voodoo lily uses heat to help spread its smell of rotting meat. This smell draws in flies which begin to search for the source of the smell. As they search the entire plant for the dead carcass, they pollinate the plant. Other theories state that the heat may provide a heat reward for the pollinator: pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrion
A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'' was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase coined by Philip Siekevitz in a 1957 article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). A large number of unicellular organisms, such as microsporidia, parabasalids and diplomonads, have reduced or transformed their mitochondria into other structures. One eukaryote, ''Monocercomonoides'', is known to have completely lost its mitochondria, and one multicellular organism, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Warm-blooded
Warm-blooded is an informal term referring to animal species which can maintain a body temperature higher than their environment. In particular, homeothermic species maintain a stable body temperature by regulating metabolic processes. The only known living homeotherms are birds and mammals, and the only living homeothermic lizard is the Argentine black and white tegu. Some extinct reptiles such as ichthyosaurs, pterosaurs, plesiosaurs and some non-avian dinosaurs are believed to have been homeotherms. Other species have various degrees of thermoregulation. Animal body temperature control varies by species, so the terms "warm-blooded" and " cold-blooded" (though still in everyday use) suggest a false idea of there being only two categories of body temperature control, and are no longer used scientifically. Terminology In general, warm-bloodedness refers to three separate categories of thermoregulation. * Endothermy is the ability of some creatures to control their body t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shivering
Shivering (also called shuddering) is a bodily function in response to cold and extreme fear in warm-blooded animals. When the core body temperature drops, the shivering reflex is triggered to maintain homeostasis. Skeletal muscles begin to shake in small movements, creating warmth by expending energy. Shivering can also be a response to fever, as a person may feel cold. During fever, the hypothalamic set point for temperature is raised. The increased set point causes the body temperature to rise (pyrexia), but also makes the patient feel cold until the new set point is reached. Severe chills with violent shivering are called rigors. Rigors occur because the patient's body is shivering in a physiological attempt to increase body temperature to the new set point. Biological basis Located in the posterior hypothalamus near the wall of the third ventricle is an area called the primary motor center for shivering. This area is normally inhibited by signals from the heat center in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arceuthobium Americanum
''Arceuthobium americanum'' is a species of dwarf mistletoe known as American dwarf mistletoe and lodgepole-pine dwarf mistletoe. It is a common plant of western North America where it lives in high elevation pine forests. It is a parasitic plant which lives upon the Lodgepole Pine, particularly the subspecies ''Pinus contortus'' ssp. ''murrayana'', the Tamarack Pine. This pine subspecies is most common in the Cascade Range and Sierra Nevada. The American dwarf mistletoe is a yellow-green coral-shaped structure above the surface of the tree's bark, while most of the parasite is beneath the bark. The seeds mature in late summer and disperse to nearby trees. This species has been found to explosively-disperse its seeds through thermogenesis. Rolena A.J. deBruyn, Mark Paetkau, Kelly A. Ross, David ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cynthia Ross Friedman
Cynthia "Cindy" Ross Friedman (1970 or 1971 – 24 December 2018) was a professor in biological sciences at Thompson Rivers University in Kamloops, British Columbia, Canada. She was inducted into the inaugural cohort of the Royal Society of Canada's College of New Scholars, Artists, and Scientists in 2014 and as a fellow of the Royal Society of Arts in 2016. Research In a ''Nature Communications'' paper, her research group showed that the parasitic flowering plant ''Arceuthobium americanum'' (Lodegpole pine dwarf mistletoe) undergoes thermogenesis (internal heat generation) to explosively discharge its seeds. Media appearances and activism She was on national radio and television in many instances not only to discuss her team's research but also to act as a spokesperson for a coalition of concerned community groups opposed to the proposed KGHM Ajax mine, a copper-gold open-pit mine project proposed to be located within 1 km of the Kamloops city boundary. Music Ross Friedm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Skunk Cabbage
''Symplocarpus foetidus'', commonly known as skunk cabbage or eastern skunk cabbage (also swamp cabbage, clumpfoot cabbage, or meadow cabbage, foetid pothos or polecat weed), is a low growing plant that grows in wetlands and moist hill slopes of eastern North America. Bruised leaves present an odor reminiscent of skunk. ''Symplocarpus'' combines the Greek word ''symploce'', meaning "connection" and ''carpos'', meaning "fruit", to indicate that the plant has a compound fruit. The genus name ''Symplocarpus'' combines two Greek words: ''Symplo-'' is derived from �υμπλoκή meaning connection, ''-carpus'' is derived from �αρπòς meaning fruit. Linnaeus gave the plant its species name of ''foetidus,'' Latin for "bad-smelling". The plant produces a strong odor, which is repulsive to many but sometimes described as smelling like "fresh cabbage with a slight suggestion of mustard". The odor increases in intensity over time, as the plant matures, likely due to increased r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Futile Cycle
A futile cycle, also known as a substrate cycle, occurs when two metabolic pathways run simultaneously in opposite directions and have no overall effect other than to dissipate energy in the form of heat. The reason this cycle was called "futile" cycle was because it appeared that this cycle operated with no net utility for the organism. As such, it was thought of being a quirk of the metabolism and thus named a futile cycle. After further investigation it was seen that futile cycles are very important for regulating the concentrations of metabolites. For example, if glycolysis and gluconeogenesis were to be active at the same time, glucose would be converted to pyruvate by glycolysis and then converted back to glucose by gluconeogenesis, with an overall consumption of ATP. Futile cycles may have a role in metabolic regulation, where a futile cycle would be a system oscillating between two states and very sensitive to small changes in the activity of any of the enzymes involved. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
