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In thermodynamics, an exothermic process (from Ancient Greek έξω (éxō) ' outward ' and θερμικός (thermikós) ' thermal ') [1] is a thermodynamic process or reaction that releases energy from the system to its surroundings, [2] usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e.g ...
Such organisms (frogs, for example) rely on environmental heat sources, [3] which permit them to operate at very economical metabolic rates. [ 4 ] Some of these animals live in environments where temperatures are practically constant, as is typical of regions of the abyssal ocean and hence can be regarded as homeothermic ectotherms.
Thermogenic plants are also protogynous, meaning that the female part of the plant matures before the male part of the same plant. This reduces inbreeding considerably, as such a plant can be fertilized only by pollen from a different plant. This is why thermogenic plants release pungent odors to attract pollinating insects.
In actuality, however, plants do not absorb all incoming sunlight (due to reflection, respiration requirements of photosynthesis and the need for optimal solar radiation levels) and do not convert all harvested energy into biomass, which results in a maximum overall photosynthetic efficiency of 3 to 6% of total solar radiation. [1]
A Q 10 of 1.0 indicates thermal independence of a muscle whereas an increasing Q 10 value indicates increasing thermal dependence. Values less than 1.0 indicate a negative or inverse thermal dependence, i.e., a decrease in muscle performance as temperature increases. [3] Q 10 values for biological processes vary with temperature.
As an example in everyday life, hand warmers make use of the oxidation of iron to achieve an exothermic reaction: 4Fe + 3O 2 → 2Fe 2 O 3 Δ H ⚬ = - 1648 kJ/mol A particularly important class of exothermic reactions is combustion of a hydrocarbon fuel, e.g. the burning of natural gas:
A germination rate experiment. Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. [1]Plant physiologists study fundamental processes of plants, such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed ...
The light-harvesting complex (or antenna complex; LH or LHC) is an array of protein and chlorophyll molecules embedded in the thylakoid membrane of plants and cyanobacteria, which transfer light energy to one chlorophyll a molecule at the reaction center of a photosystem. The antenna pigments are predominantly chlorophyll b, xanthophylls, and ...