Centrifugation Flashcards

1
Q

What is benchtop centrifuge used for?

A

Used to separate whole cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is typical speed of benchtop centrifuge?

A

Few hundred to 3000 rpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is high speed centrifuge used for?

A

Used for subcellular fractionation

Used to separate organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is typical speed for high speed centrifuge?

A

Up to 20,000 rpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is microcentrifuge used for?

A

Used to purify DNA + RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is typical speed of micro centrifuge ?

A

Up to 20,000 rpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is ultracentrifuge used for?

A

Used for nucleic acid purification

Used for subcellular fractionation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does rate of sedimentation of particle depends on?

A

Centrifugal force
Buoyant density
Frictional drag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

More massive the particle, the …… centrifuge force so …….it will sediment

A

Bigger

Faster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

For given mass, the more ….. the particle the ….. it will sediment=> more ……so….. drag therefore ….. buoyancy

A
Dense 
Faster 
Compact 
Less 
Less
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Centrifugal force depends on mass of particle + acceleration
What is the equation for force? And what is its units?

A

Force= mass x acceleration

Force is measured in Newtons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Acceleration depends on distance from axis and the rate of spin squared
What is the equation for acceleration?

A

Acceleration= w^2r
w=rate of spin
r= distance from axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is typical speed for ultracentrifuge?

A

Up to 80,000 rpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Sedimentation rate is measured in …….

A

Svedberg units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are some practical points of centrifuge?

A

Sample in centrifuge must be balanced
Every tube must have another directly opposite
Tubes must contain same volume of fluid
Low speed centrifuge + microcentrifuge=> balance tubes by eye
High speed centrifuge + ultracentrifuge=> balance tubes by weighing them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens if mammalian cells are centrifuged at high speeds?

A

Cells may lyse due to shear forces

17
Q

Mammalian cells can be broken open by:

A

Mechanical stress in homogeniser
Ultrasonication
Mild detergent treatment

18
Q

How can you purify nucleic acids?

A

Add NaCl solution
Add ethanol to final concentration of 70%
Centrifuge at 5-10,000g
Rinse pellet in 70% ethanol + spin again
Remove supernatant
Allow pellet to air dry

19
Q

What does isopynic mean?

A

Means equal density

20
Q

Nucleic acids can be purified and separated by ……… in ………

A

Isopynic centrifugation in caesium chloride density