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.
In general, a matrix is the place where something develops. For instance, the nail matrix is where the nail develops. Alternatively, it is a mechanism for harvesting electriciâ¦ty from an organism while creating a virtual reality envornment to keep the organism oblivious to its metareality.