Cell, spectral analysis of

Article By:

Bonner, Walter D., Jr. Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Vanderkooi, Jane M. Department of Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Last reviewed:November 2019

DOI:https://doi.org/10.1036/1097-8542.116020

Living cells contain various substances, the concentrations and biological activity of which can be investigated by observing the spectrum of light passed through the cells. Such investigations take advantage of the fact that many substances absorb light in an individually characteristic manner. Thus, the spectrum of light passed through a green leaf has two black bands where red and blue light should appear. The absorption of red and blue light is characteristic of the chlorophylls, the photosynthetic pigments. Today, investigations of cells by optical methods go far beyond the routine analysis of brightly colored pigments that are found widespread and in high concentration, for example, hemoglobin and chlorophyll. Such methods allow the investigation of light-absorbing molecules within the cell whose concentration is 1000 times smaller that that of hemoglobin or of chlorophyll. See also: Chlorophyll; Hemoglobin

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