Final answer:
Side scatter in flow cytometric analysis provides information about a cell's granularity and complexity of internal structures, which is used to differentiate cells and is crucial for applications like immunofluorescence and fluorescence-activated cell sorting (FACS).
Step-by-step explanation:
In flow cytometric analysis, side scatter (SSC) of a laser light beam provides information that pertains to a cell's granularity and complexity of internal structures. While forward scatter (FSC) is mainly related to the size of a cell, side scatter is useful in distinguishing cells based on their internal complexity, such as the quantity and types of granules present within them, which affect how light is refracted within the cell.
Side scatter gives an indication of how complex a cell's internal structure is, with higher SSC values often associated with granular leukocytes like neutrophils, and lower values with lymphocytes which have fewer internal structures. This property of flow cytometry is utilized for differentiating cells in a heterogeneous mixture and is crucial for applications like immunofluorescence and fluorescence-activated cell sorting (FACS). The latter technique further separates cells into populations based on the intensity of fluorescence emitted, which corresponds to the presence and quantity of specific markers or proteins identified by fluorophore-conjugated antibodies.