Final answer:
In flow cytometry, forward scatter is a measure of cell size, where larger cells scatter more light in the forward direction, providing an estimate of their relative size.
Step-by-step explanation:
In flow cytometry, forward scatter (FSC) is generally considered a measure of cell size. This is because as a cell passes through the laser beam, the light is scattered in various directions. The light that goes in the same direction as the laser, but is slightly scattered, is what we refer to as forward scatter. Larger cells tend to scatter more light in the forward direction than smaller cells. This property allows researchers to estimate the relative size of cells within a mixed population. Meanwhile, side scatter (SSC), which is detected at a ninety-degree angle to the laser axis, relates more closely to the granularity or complexity of the cell, such as the presence of granules or organelles within the cells.