Cell Fractionation and Differential Centrifugation

Flashcards covering the stages, conditions, processes, and terminology of cell fractionation and differential centrifugation.

What is cell fractionation?

The process of breaking up cells and separating their organelles.

What are the two main stages of cell fractionation?

Homogenisation and differential centrifugation.

Why is the sample kept cold during cell fractionation?

To reduce enzyme activity and prevent organelles from being broken down.

Why is an isotonic solution used during cell fractionation?

To prevent organelles bursting or shrinking due to osmosis.

Why is a buffered solution used during cell fractionation?

To maintain a constant pH and prevent damage to organelles and enzymes.

What is homogenisation?

Breaking open cells using a homogeniser to release organelles.

What is a homogenate?

The fluid mixture containing released organelles and cell components.

Why is the homogenate filtered?

To remove whole cells and large pieces of debris.

What is differential centrifugation?

Separating organelles by spinning the sample at different speeds.

What is ultracentrifugation?

Using very high-speed centrifugation to separate smaller cell components.

What is a pellet?

The dense solid material collected at the bottom of the centrifuge tube.

What is a supernatant?

The liquid remaining above the pellet.

Which organelles sediment first during centrifugation?

The largest and densest organelles, such as nuclei.

Why are different centrifugation speeds used?

To separate different organelles according to their size and density.

What happens to the supernatant after centrifugation?

It can be transferred and centrifuged again at a higher speed to separate smaller organelles.

Why is cell fractionation called differential centrifugation?

Because different organelles sediment at different centrifugation speeds.