Biology - cell fractionation

Cellular compartmentalization is accomplished in part by various subcellular organelles.

With this technique, the heaviest or most dense organelles, nuclei pellet in less time and with less force than is required to pellet lighter organelles such as mitochondria.

First, a cell homogenate is made by rupturing the cell membranes in the tissue.

The homogenate is then centrifuged for a short period of time to remove cell debris and nuclei.

Cellular compartmentalization provides efficiency by bringing together related compounds that can interfere with each other (i.e. lysosomal hydrolytic enzymes).

Cellular Fractionation

The arrangement of macromolecules within a cell is as important to cellular function as their catalytic activities.

Most chlorophyll-free plant tissues are acceptable for preparing mitochondria, but recently-harvested plant tissues are usually required, making their use uncertain during winter months.

First, a cell homogenate is made by rupturing the cell membranes in the tissue.

Homogenizers have a precise clearance between the glass tube and pestle, which breaks the cell membrane leaving the smaller organelle membranes intact.

In this lab module, we will isolate several subcellular organelle fractions from liver cells, and will examine their various properties.

With this technique, the heaviest or most dense organelles, nuclei pellet in less time and with less force than is required to pellet lighter organelles such as mitochondria.

With this technique, the heaviest or most dense organelles, nuclei pellet in less time and with less force than is required to pellet lighter organelles such as mitochondria.

Homogeneous cell populations from cell culture are well suited for cell fractionation.

Some tissues, like those in the liver also have one cell type that predominates, so are also well suited.

This can be done by analyzing each organelle fraction for organelle-specific marker enzymes.

For this type of fractionation, which tissue we use, and the method of homogenization are dictated by the biological system.

The method we will use to separate the various organelles utilizes differential centrifugation to isolate components of different densities.

This can be done by analyzing each organelle fraction for organelle-specific marker enzymes.

Most chlorophyll-free plant tissues are acceptable for preparing mitochondria, but recently-harvested plant tissues are usually required, making their use uncertain during winter months.