eyeball. 1  Photoreceptors are the cells in the retina that respond to light. Their distinguishing feature is the presence of large amounts of tightly packed membrane that contains the photopigment rhodopsin or a related molecule.
In chemical analysis,  matrix refers to the components of a sample other than the analyte of interest. The matrix can have a considerable effect on the way the analysis is conducted and the quality of the results obtained; such effects are called matrix effects. For example, the ionic strength of the solution can have an effect on the activity coefficients of the analytes.
The definition of a matrix is an environment in which something is created or the rock in which a crystal or fossil is embedded. 1  An example of a matrix is the Constitution from which democracy was born.2  An example of a matrix is a chunk of rock in which amethyst crystals are formed.INK / CITE ADD TO WORD LIST. noun. The definition of a matrix is an environment in which something is created or the rock in which a crystal or fossil is embedded. 1  An example of a matrix is the Constitution from which democracy was born. 2  An example of a matrix is a chunk of rock in which amethyst crystals are formed.