Cell Fractionation and Differential Centrifugation

Purpose

• Cell Fractionation: A technique used to study the different parts of a cell by separating them based on their size and density.

Process Overview

1. Homogenization

   • Cells are broken apart.
   • Plasma membranes are disrupted, allowing internal contents to mix into a homogenate.

2. Centrifugation

   • The process of spinning the homogenate at high speeds to separate cell components.
   • Also known as Differential Centrifugation due to varying speeds used for different components.

Steps of Differential Centrifugation

• 1,000 G's:

  • Produces a pellet rich in nuclei and cell debris.
  • Leaves a liquid portion (supernatant) containing smaller components.

• 20,000 G's:

  • Supernatant is further centrifuged.
  • Produces a pellet rich in mitochondria.

• 80,000 G's:

  • Further centrifugation of supernatant.
  • Produces a pellet rich in microsomes (pieces of plasma membrane and internal membranes).

• 150,000 G's:

  • Final centrifugation of supernatant.
  • Produces a pellet rich in ribosomes.

Significance

• Isolation of subcellular components allows detailed study of individual organelles’ roles and structures.
• Enables researchers to understand the specific functions of cellular components in greater detail.