Ultracentrifuge

Definition

An ultracentrifuge is a high-speed centrifuge used to separate particles in a solution based on their size, shape, and density. It operates at extremely high speeds to generate significant centripetal acceleration.

5 Must Know Facts For Your Next Test

1. Ultracentrifuges can reach speeds up to 1,000,000 RPM, creating accelerations many times greater than gravity.
2. The centripetal acceleration in an ultracentrifuge is given by the formula $a_c = \omega^2 r$, where $\omega$ is the angular velocity and $r$ is the radius of rotation.
3. Ultracentrifuges are essential for separating macromolecules like proteins, nucleic acids, and viruses due to their precise control over rotational speed and temperature.
4. The rotor design in ultracentrifuges must withstand immense forces; materials like titanium and carbon fiber are commonly used.
5. Centripetal force acting on particles during ultracentrifugation can be calculated using $F_c = m\omega^2 r$, where $m$ is the mass of the particle.

Review Questions

• How does an ultracentrifuge create centripetal acceleration?
• What factors determine the separation efficiency in an ultracentrifuge?
• Why are specific materials like titanium used in the construction of ultracentrifuge rotors?

Related terms

Centripetal Force: The force that keeps a body moving in a circular path, directed towards the center of rotation.

Angular Velocity: The rate of change of angular displacement, usually measured in radians per second.

Sedimentation Coefficient: A measure of how quickly a particle sediments when subjected to centrifugal force, typically expressed in Svedberg units (S).