Levels of Organization Image Map
Step 1: Centrifuge

The first step in many protein studies is to separate cellular parts first, so
that you can study the proteins in specific parts of the cell, such as proteins in the nucleus, for example.

One popular approach is to centrifuge cells at high speeds. This is like those rides in amusement parks that spin you around and around in a horizontal plane. To get the best separation of cell parts, you must use very expensive centrifuges that spin at enormous speeds. This separates the components of the cells according to their weight. For example, chromosomes are heavy, so they would be slung down toward the bottom of the tube. Lighter weight organelles would be located toward the top.

Centrifugation works best if cells are broken up and put in a liquid that can suspend the cell parts in different layers. A gradient of different organelles of concentrations is a very popular solvent system for separating different parts of a cell (mitochondria spin down in one layer of the solvent, membranes in another, chromosomes in another, and so on).