Which technique involves breaking cells into pieces and separating their parts?

Cell fractionation is the technique that specifically involves breaking cells into pieces and then using various methods to separate their components based on size, density, or other characteristics. This process allows researchers to study the individual parts of a cell, such as organelles, membranes, and cytoplasmic components, in isolation, which is essential for understanding their specific functions and roles within the cell.

During cell fractionation, cells can be disrupted using methods such as homogenization or sonication. The resulting mixture contains various cellular components that can then be separated through centrifugation or other separation techniques. By subjecting the homogenate to different centrifugal forces, components can settle at different rates, allowing for the isolation of specific organelles or cellular structures.

In contrast, while cell culturing grows cells in controlled environments, electrophoresis is primarily used for separating nucleic acids or proteins based on size and charge after they have been isolated, and filtration involves separating particles from liquids or gases without specifically breaking cells apart. Therefore, the focus on breaking cells and separating their components distinctly identifies cell fractionation as the correct answer.