(C) General Equipment

Question 1

Describe the principle of electronic analytical balances.

Answer 1

Electromagnetic force used to counter balance the load placed on the pan.

Question 2

Describe the difference between a Water Bath and a Heat Block.

Answer 2

Water Baths: heats samples/reagents/chemicals, melt substrates, incubates cell cultures; heats up to 99C.

Heat Block: heats samples/reagents; heats up to 150C.

Question 3

Centrifuges cause (more dense/less dense) components to settle to the bottom.

Answer 3

more dense.

Question 4

Define precipitate.

Answer 4

Solid material (denser components) at the bottom of the tube.

Question 5

Define supernatant.

Answer 5

Liquid (less dense components) on the top.

Question 6

Describe the three main parts of the centrifuge.

Answer 6

Rotor, drive shaft, motor.

Question 7

The benefit of fixed head centrifuges is…

Answer 7

Can withstand higher gravitational forces allowing for higher speeds.

Question 8

How is Relative Centrifugal Force (RCF) calcuated?

Answer 8

RPM + Centrifugal Force (measured in units of gravity).

RCF = (1.12x10^-5)(r)(rpm)^2
where r = rotator radius in cm

Question 9

What is the centrifuge speed needed for serum separator tubes with a silicone gel?

Answer 9

Usually between 1000 - 1300g for 10 minutes.

Question 10

What measuring device is used for verification of rotation speed?

Answer 10

Tachometer.

Question 11

What measuring device is used for verification of rotation speed?

Answer 11

Tachometer.