| Haeckel's gastrea theory | That the two-layered gastrula is the ancestral form of all multicellular animals. Synonym: gastrea theory. (05 Mar 2000) |
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| Haeckel's law | The theory formulated by E.H. Haeckel that individuals in their embryonic development pass through stages similar in general structural plan to the stages their species passed through in its evolution; more technically phrased, the theory that ontogeny is an abbreviated recapitulation of phylogeny. Synonym: biogenetic law, law of biogenesis, Haeckel's law, law of recapitulation. (05 Mar 2000) |
| Haeckel, Ernst | <person> German naturalist, 1834-1919. See: Haeckel's gastrea theory, Haeckel's law. (05 Mar 2000) |
| haem | 1. <biochemistry> Compounds of iron complexed in a porphyrin (tetrapyrrole) ring that differ in side chain composition. Haems are the prosthetic groups of cytochromes and are found in most oxygen carrier proteins. 2. <prefix> haem-, eaning relating to blood. Origin: G. Haima (21 Jun 2000) |
| haem a | A derivative of haem found in cytochrome aa3. (05 Mar 2000) |
| haem A-farnesyltransferase | <enzyme> Required for synthesis of cytochrome oxidase and haem a synthesis; found in mitochondria of saccharomyces cerevisiae; has been sequenced Registry number: EC 2.5.1.- Synonym: cox10 gene product, cox10 protein (26 Jun 1999) |
| haem c | A derivative of haem found in cytochromes c, b4, and f. (05 Mar 2000) |
| haem oxygenase (decyclizing) | <enzyme> A mixed function oxidase enzyme which during haemoglobin catabolism catalyses the degradation of haem to ferrous iron, carbon monoxide and biliverdin in the presence of molecular oxygen and reduced NADPH. The enzyme is induced by metals, particularly cobalt. Chemical name: Haem,hydrogen-donor:oxygen oxidoreductase (alpha-methene-oxidizing, hydroxylating) Registry number: EC 1.14.99.3 (12 Dec 1998) |
| haem polymerase | <enzyme> Malarial enzyme forms haemozoin from haem derived from haemoglobin; no information on mechanism 2/92 Registry number: EC 2.- Synonym: haem polymerase (26 Jun 1999) |
| haemachrome | <physiology> Hematin. Origin: Haema- + Gr. Colour. Source: Websters Dictionary (01 Mar 1998) |
| haemachrosis | An intensified redness of the blood. Origin: haema-+ G. Chrosis, colouration (05 Mar 2000) |
| haemacyanin | <physiology> A substance found in the blood of the octopus, which gives to it its blue colour. When deprived of oxygen it is colourless, but becomes quickly blue in contact with oxygen, and is then generally called oxyhaemacyanin. A similar blue colouring matter has been detected in small quantity in the blood of other animals and in the bile. Origin: Haema- + Gr. A dark blue substance. Source: Websters Dictionary (01 Mar 1998) |
| haemacyte | <haematology> A red blood cell. (27 Sep 1997) |
| haemacytometer | <instrument, microscopy> A glass slide with a chamber for counting blood corpuscles in a given volume. The cells are 0.1 mm deep and are made with several types of ruling. Such cells are convenient counting chambers for many other kinds of suspensions. (05 Aug 1998) |
| haemacytozoon | A protozoon parasite of the blood cells. Synonym: haemacytozoon, haematocytozoon. Origin: haemo-+ G. Kytos, cell, + zoon, animal (05 Mar 2000) |