molecular mass

mo·lec·u·lar weight (mol wt, MW),

the sum of the atomic weights 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 (M_r) is the mass relative to the dalton and has no units.
See also: atomic weight.

Synonym(s): molecular mass, molecular weight ratio, relative molecular mass

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mass

(mas) [L. massa, mass fr Gr. maza, (barley) cake]

1. A quantity of material, such as cells, that unite or adhere to each other.

2. Soft solid preparation for internal use and of such consistency that it may be molded into pills.

3. A fundamental scalar property of an object that describes the amount of acceleration an object will have when a given force is applied to it. The metric unit of mass is the kilogram. One kilogram equals 2.205 pounds. See: weight

4. Large, extensive, or encompassing an entire organ or population group (e.g., a mass vaccination).

cell mass

In embryology, the mass of cells that develops into an organ or structure.

epithelial mass

The inner portion of a developing gonad enclosed within the germinal epithelium.

fat mass

Total body fat. It can be measured with dual energy absorptiometry or bioelectrical impedance techniques.

fat-free mass

The lean body mass plus the skeletal mass.

formula mass

Gram molecular mass.

gram molecular mass

The mass or weight in grams of a substance equal to its molecular mass/weight.

Synonym: formula mass; gram molecular weight

inner cell mass

In embryology, the group of cells within the blastocyst from which the embryo, yolk sac, and amnion develop.

See: blastocyst

intermediate cell mass

A plate of nonsegmented mesoderm lying lateral to the segments (somites) and connecting them to the nonsegmented lateral mesoderm. Synonym: nephrotome

lateral mass of the atlas

The parts of the first cervical vertebra that articulate with the occipital bone superiorly and the axis inferiorly.

lean body mass

The weight of the body minus the fat content. It includes bones, muscles, and internal organs.

molecular mass

Molecular weight.

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