| bond dissociation energy | This is the energy needed to break the bonds between two linked atoms. (09 Oct 1997) |
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| bond energy | The energy needed to break a molecular bond. (09 Oct 1997) |
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| high energy bond | <chemistry> Chemical bonds that release more than 25kJ/mol on hydrolysis: their importance is that the energy can be used to transfer the hydrolysed residue to another compound. The risk in using the term is that students may think the bond itself is different in some way, whereas it is the compound that matters. Hydrolysis of creatine phosphate yields 42.7kJ/mol, of phosphoenolpyruvate, 53.2, ATP to ADP, 30.5: the latter is important because it shows that energetically the hydrolysis of creatine phosphate will suffice to reconstitute ATP, hence the use of creatine phosphate in muscle. (18 Nov 1997) |
| high energy phosphate bond | See: high energy phosphates. (05 Mar 2000) |
| energy-rich bond | See: high energy compounds. (05 Mar 2000) |
| acid dissociation constant | <chemistry> This is the equilibrium constant for the breaking apart of a weak acid into its hydrogen and conjugate base in a water solution. (09 Oct 1997) |
| albuminocytologic dissociation | Increased protein in the cerebrospinal fluid without increase in cell count, characteristic of the Guillain-Barre syndrome; it is also associated with spinal block and with intracranial neoplasia, and is seen in the last phases of poliomyelitis. (05 Mar 2000) |
| atrial dissociation | Mutually independent beating of the two atria or of parts of the atria. (05 Mar 2000) |
| atrioventricular dissociation | Any situation in which atria and ventricles are activated and contract independently, as in complete A-V block, more specifically, the dissociation between atria and ventricles that results from slowing of the atrial pacemaker or acceleration of the ventricular pacemaker at nearly equal (rarely equal) rates, each depolarising its own chamber, thus interfering with depolarisation by the other (interference-dissociation). (05 Mar 2000) |
| A-V dissociation | Any situation in which atria and ventricles are activated and contract independently, as in complete A-V block, more specifically, the dissociation between atria and ventricles that results from slowing of the atrial pacemaker or acceleration of the ventricular pacemaker at nearly equal (rarely equal) rates, each depolarising its own chamber, thus interfering with depolarisation by the other (interference-dissociation). (05 Mar 2000) |
| base dissociation constant | <chemistry> This is the equilibrium constant for the reaction in which a weak base breaks apart in water to form its conjugate acid and hydroxide ion. (09 Oct 1997) |
| molecular dissociation theory | A theory, pertaining to colour vision, that gray is the earliest of colour sensations, from which are derived, by molecular change, two paired substances that, respectively, detect yellow and blue, and that the yellow gives rise to paired substances for detection of red and green. Synonym: Ladd-Franklin theory. (05 Mar 2000) |
| complete atrioventricular dissociation | A-V dissociation not interrupted by ventricular captures. Synonym: complete A-V block. (05 Mar 2000) |
| heat of dissociation | The heat (expressed in calories or joules) expended in the dissociation of 1 mol of a substance into specified products. (05 Mar 2000) |
| pupillary light-near dissociation | A stronger near pupil response than light response; due to weak pupillomotor input, Argyll Robertson pupil, dorsal midbrain syndrome, or to misdirection of ciliary muscle fibres into the iris sphincter. Synonym: light-near dissociation. (05 Mar 2000) |
| sleep dissociation | <neurology, physiology> A condition that occurs in REM stage sleep. There is no movement of the skeletal muscles in this stage of sleep. See: REM stage sleep. (27 Sep 1997) |