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Endocrinology (from endocrine + -ology) is a branch of biology and medicine dealing with the endocrine system, its diseases, and its specific secretions known as hormones.It is also concerned with the integration of developmental events proliferation, growth, and differentiation, and the psychological or behavioral activities of metabolism, growth and development, tissue function, sleep ...
The optimality hypothesis states too much variability in the MHC can result in a failure of T-cells to distinguish themselves non-selves, and thereby increase the risk of autoimmune disease. This would confer greater fitness to individuals without a large degree MHC diversity. [6] [13] Autoimmune diseases are associated with MHC loci. In humans ...
One hypothesis states that when Venus had water, solar radiation was as low as 30% less than it is today. This means the habitable zone was stretched from Venus to Earth (and possibly to Mars ), before eventually Solar maxima began creating greenhouse gases in Venus’ atmosphere, making the atmosphere thicker, evaporating away all liquid water ...
The aromatic/arginine or "ar/R" selectivity filter is a cluster of amino acids that help bind to water molecules and exclude other molecules that may try to enter the pore. It is the mechanism by which the aquaporin is able to selectively bind water molecules and so to allow them through, and to prevent other molecules from entering.
Fluid mosaic model of a cell membrane. The fluid mosaic model explains various characteristics regarding the structure of functional cell membranes.According to this biological model, there is a lipid bilayer (two molecules thick layer consisting primarily of amphipathic phospholipids) in which protein molecules are embedded.
Hormones can be amino acid complexes, steroids, eicosanoids, leukotrienes, or prostaglandins. [3] The endocrine system is contrasted both to exocrine glands, which secrete hormones to the outside of the body, and to the system known as paracrine signalling between cells over a relatively short distance.
The hydrophobicity hypothesis states that highly hydrophobic (water hating) proteins (such as the membrane bound proteins involved in redox reactions) are not easily transported through the cytosol and therefore these proteins must be encoded in their respective organelles. The code disparity hypothesis states that the limit on transfer is due ...
Organic molecules on the early Earth could have had either terrestrial origins, with organic molecule synthesis driven by impact shocks or by other energy sources, such as ultraviolet light, redox coupling, or electrical discharges; or extraterrestrial origins (pseudo-panspermia), with organic molecules formed in interstellar dust clouds ...