| proportion | 1. The relation or adaptation of one portion to another, or to the whole, as respect magnitude, quantity, or degree; comparative relation; ratio; as, the proportion of the parts of a building, or of the body. "The image of Christ, made after his own proportion." (Ridley) "Formed in the best proportions of her sex." (Sir W. Scott) "Documents are authentic and facts are true precisely in proportion to the support which they afford to his theory." (Macaulay) 2. Harmonic relation between parts, or between different things of the same kind; symmetrical arrangement or adjustment; symmetry; as, to be out of proportion. "Let us prophesy according to the proportion of faith." 3. The portion one receives when a whole is distributed by a rule or principle; equal or proper share; lot. "Let the women . . . Do the same things in their proportions and capacities." (Jer. Taylor) 4. A part considered comparatively; a share. 5. <mathematics> The equality or similarity of ratios, especially of geometrical ratios; or a relation among quantities such that the quotient of the first divided by the second is equal to that of the third divided by the fourth; called also geometrical proportion, in distinction from arithmetical proportion, or that in which the difference of the first and second is equal to the difference of the third and fourth. Proportion in the mathematical sense differs from ratio. Ratio is the relation of two quantities of the same kind, as the ratio of 5 to 10, or the ratio of 8 to 16. Proportion is the sameness or likeness of two such relations. Thus, 5 to 10 as 8 to 16; that is, 5 bears the same relation to 10 as 8 does to 16. Hence, such numbers are said to be in proportion. Proportion is expressed by symbols thus: a:b::c:d, or a:b = c:d, or a/b = c/d. The rule of three, in arithmetic, in which the three given terms, together with the one sought, are proportional. Continued proportion, Inverse proportion, etc. See Continued, Inverse, etc. Harmonical, or Musical, proportion, a relation of three or four quantities, such that the first is to the last as the difference between the first two is to the difference between the last two; thus, 2, 3, 6, are in harmonical proportion; for 2 is to 6 as 1 to 3. Thus, 24, 16, 12, 9, are harmonical, for 24:9::8:3. In proportion, according as; to the degree that. "In proportion as they are metaphysically true, they are morally and politically false." Origin: F, fr. L. Proportio; pro before + portio part or share. See Portion. Source: Websters Dictionary (01 Mar 1998) |
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| zone of optimal proportion | <chemistry> A zone in a solution of mixed antigen in which the two biomolecules are totally combined. (11 May 1997) |
| active mutant | A mutant with overt phenotypic expression. (05 Mar 2000) |
| amber mutant | A mutant with a mutation resulting in a UAG codon. (05 Mar 2000) |
| auxotrophic mutant | Mutant with a nutritional requirement not present in the wild type organism. Synonym: defective organism, deficiency mutant. (05 Mar 2000) |
| gap mutant | <molecular biology> A fruit fly of the genus Drosophila which is missing a number of adjacent segments because the segments failed to develop. (09 Oct 1997) |
| rats, mutant strains | Rats bearing mutant genes which are phenotypically expressed in the animals. (12 Dec 1998) |
| virulent phage mutant | A mutant of a phage that is unable to establish lysogeny. (05 Mar 2000) |
| relaxed mutant | A mutant bacterium that continues to synthesise RNA in a medium that lackscertain nutrients or amino acids which that sort of bacterium normallyneeds present before it can make RNA. (09 Oct 1997) |
| ced mutant | <organism> Giant multinucleate fresh water amoeba (up to 5mm long) much used for studies on the mechanism of cell locomotion. (18 Nov 1997) |
| cell division cycle mutant | A yeast cell which has cell division cycle genes that have mutated to become sensitive to temperature, at certain temperatures (usually high ones), various parts of the normal yeast cell cycle become abnormal, and in some strains the yeast cell does not survive at all. (09 Oct 1997) |
| petite mutant | <molecular biology, organism> A class of yeast mutants, most studied in Saccharomyces cerevisiae. Mutants grow slowly and rely on anaerobic respiration: mitochondria, although present, have reduced cristae and are functionally defective (termed promitochondria). There are three types of petite mutant: (i) Segregational mutants that show Mendelian behaviour and result from mutations in mitochondrial genes located in the nucleus. (ii) Neutral petites, which are recessive genotypes and result from the complete absence of mitochondrial DNA. (iii) Suppressive petites, in which most of the mitchondrial DNA is lost (60-99%), though what remains is often amplified. (06 Oct 1997) |
| mice, mutant strains | Mice bearing mutant genes which are phenotypically expressed in the animals. (12 Dec 1998) |
| minute mutant | <genetics, molecular biology> A class of recessive lethal mutants of Drosophila The heterozygotes grow more slowly, are smaller and less fertile than the wild type flies. There are about 40 loci that produce minute mutants. (18 Nov 1997) |
| cold-sensitive mutant | A mutant that is defective at low temperature but functional at normal temperature. Compare: temperature-sensitive mutant. (05 Mar 2000) |