Centrifugation Flashcards
Centrifugation
The separation of components in a suspension form of a complex mixture by applying centrifugal force
Rotation per minute is expressed in the form of
Angular velocity
First ultracentrifuge was developed by
Svedberg
What will happen if the density of the solution and the particle is same?
No sedimentation will occur
Name the two types of rotors
Fixed type and Swing type
Name the some types of Swing rotors
Verticle and horizontal
Which rotors give better resolution, horizontal or vertical?
Verticle
What is sedimentation coefficient?
The ratio of particle’s sedimentation velocity to the applied acceleration causing sedimentation
What is unit of sedimentation coefficient? And what is its value?
Svedberg
S = 10-¹³ sec
Why is differential centrifugation or differential pelleting used?
Used to separate cell organelles and membrane.
What is density gradient centrifugation?
Density of a solution in this centrifugation increases from top to bottom of the centrifuge tube.
What is the use of density gradient centrifugation?
It is used to purify large volume biomolecule and different viruses.
Name the two types of density gradient centrifugation.
Rate zonal ultracentrifugation
Equilibrium density gradient ultracentrifugation or Isopycnic density
What are the unique characteristic of rate zonal ultracentrifugation?
The density of the solution isn’t more than the particle’s density.
Forms zone or pellet
Separation in rate zonal ultracentrifugation depends on what?
Based on size, shape, time, density and sedimentation coefficient
What is separated in rate zonal ultra centrifugation?
Polyzome and ribosome sub unit
Similarly shaped macromolecules
Isopycnic density centrifugation seperates particle on the basis of?
Densities
What are the unique characteristics of isopycnic centrifugation?
Density is greater than the particle’s density
Sedimentation never at the bottom of the tube
No zone formed
Name the two modes of centrifugation
Preparative centrifugation
Analytical centrifugation
Why is preparative centrifugation used?
To separate small microscopic particles like protein, DNA, lipoprotein, RNA, plasmid.
Sucrose gradient is used for what?
To seperate cellular organelles
Caesium gradient is used to separate?
Nucleic acid
Analytical centrifugation is used for?
To determine the type of molecule, confirmational changes and stoichiometry of the subunit.
Determines sedimentation rate too
Ultracentrifuge? Separates what particle?
Extremely high speed, under vacuum. Separation of ribosomes, proteins, and viruses.
Uses of ultracentrifuge
Determine shape, size, density of macromolecules. Determine stoichiometry and purification of macromolecules
Maximum RCF of ultracentrifuge
600,000 x g
In Isopycnic centrifugation, when does the particle stop at a certain position?
When they reach equilibrium, i.e.when they reach their Isopycnic density (particle’s density is equal to the density of medium)
