MATRIC NO:03/47KC205
DEPARTMENT:Biochemistry
LEVEL:200L
SCHOOL:university of ilorin
ASSIGNMENT: DIFFERENCES BETWEEN DENSITY GRADIENT CENTRIFUGATION AND DIFFERENTIAL CENTRIFUGATION,AUTORADIOGRAPHY AND CYTOCHEMISTRY.
Density gradient centrifugation Separation of molecules and particles on the basis of buoyant density, by centrifugation in a concentrated sucrose or caesium chloride solution.
Differential centrifugation This is a technique that allows the separation of cells, organelles and macromolecules, depending on their size, shape and density.. The difference between differential and Density gradient centrifugation includes; In differential centrifugation
1. homogenized organ is used and placed in centifuge tube,
2. separation is based on speed which is dependent on weight and resistance in moving through the suspension medium
3. no sugar solution is required
4. it is easier
5. no contamination of organelles while,
In Density gradient centrifugation;
1. homogenized solution is used
2. separation is based on density
3. only occur in sucrose solution or any sugar solution
4. difficult to carry out
5. there is always some contaminations
autoradiography :
A process by which radioactive materials, often though not exclusively incorporated into cell structures, are located by exposure to a photographic emulsion forming a pattern on the film corresponding to the location of the radioactive compounds within the cell.
A technique in which radioactive molecules make their location known by exposing photographic films or emulsions.
For example,
1. The application of radioactive phosphorus, autoradiography made it possible to observe very intensive metabolism in growing bone,
2. The application of radioactive iodine and autoradiography permitted the ascertainment of the laws governing the activity of the thyroid gland,
3.And the introduction of labeled compounds