| sliding filament hypothesis | The theory that the contracting muscle shortens because two sets of filaments slide past each other. (05 Mar 2000) |
|---|---|
| Starling's hypothesis | The principle that net filtration through capillary membranes is proportional to the transmembrane hydrostatic pressure difference minus the transmembrane oncotic pressure difference; although well established, it is called Starling's hypothesis to distinguish it from Starling's law of the heart. (05 Mar 2000) |
| Neyman-Pearson statistical hypothesis | A formal conjecture about the numerical value of a parameter to be tested exclusively in the light of an immediate set of data without attention to prior knowledge or convictions and ignoring other sets of evidence treated in a similar fashion. The answer is a statement not about whether the hypothesis is true but whether it is an acceptable explanation of the data or should be rejected in favour of another hypothesis. (05 Mar 2000) |
| null hypothesis | The assumption that any observed difference between two samples of a statistical population is purely accidental and not due to systematic causes. (05 Dec 1998) |
| dual recognition hypothesis | An outmoded hypothesis that is known to be incorrect now that the structure of the T-cell receptor is known. The proposal was that viral (and some chemical) antigens were recognised in association with histocompatibility antigens by separate receptors on the T-cell. The generation of cytotoxic T-cells was by association with Class I MHC antigens, of T helper cells by association with Class II MHC antigens. See: altered self hypothesis. (18 Nov 1997) |
| insular hypothesis | An obsolete theory of the origin of diabetes mellitus from destruction or loss of function of the islets of Langerhans in the pancreas. (05 Mar 2000) |
| endosymbiont hypothesis | The hypothesis that semi autonomous organelles such as mitochondria and chloroplasts were originally endosymbiotic bacteria or cyanobacteria. The arguments are convincing and although the hypothesis cannot be proven it is widely accepted. (18 Nov 1997) |
| uniform rate hypothesis | <biology> This states that any two evolving organismal lineages diverge from a common ancestor at a constant rate with respect to each other. (09 Oct 1997) |
| unineme hypothesis | <cell biology, molecular biology> This states that that a chromatid has only one DNA duplex, which goes from one end of the chromatid to the other. (09 Oct 1997) |
| zwitter hypothesis | That an amphoteric molecule (e.g., an amino acid) has, at its isoelectric point, equal numbers of positive and negative charges, thus becoming a zwitterion. (05 Mar 2000) |
| frustration-aggression hypothesis | The theory that frustration may lead to aggression, but that aggression is always the result of some form of frustration. (05 Mar 2000) |
| Lyon hypothesis | <genetics> Hypothesis, first advanced by Lyon, concerning the random inactivation of one of the two X chromosomes of the cells of female mammals. In consequence females are chimaeric for the products of the X chromosomes, a situation that has been exploited in female Negroes (who are heterotypic for isozymes of glucose 6 phosphate dehydrogenase) as a means to confirm the monoclonal origin of papillomas and of atherosclerotic plaques. (20 Mar 1998) |
| relative molecular mass | The sum of the atomic weight's of all the atoms constituting a molecule; the mass of a molecule relative to the mass of a standard atom, now 12C (taken as 12.000). Relative molecular mass (Mr) is the mass relative to the dalton and has no units. See: atomic weight. Synonym: molecular mass, molecular weight ratio, relative molecular mass. (05 Mar 2000) |
| gram-molecular weight | Molecular weight expressed in grams. Compare: mole. (05 Mar 2000) |
| cloning, molecular | The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells. (12 Dec 1998) |