[Revision] Centrifugation

How might solid sodium carbonate be obtained from sodium carbonate solution?

• Centrifugation

• Filtration

• Evaporation

• It cannot be extracted

After centrifugation when sublimate settles, clear liquid

• can be allowed to rest

• can be allowed to form crystals

• can be decanted off

• can be evaporated

After centrifugation, sublimate

• dissolves completely

• remain suspended in a liquid

• settles at bottom

• depends upon pH of sublimate

Which of the following is an effective way of purifying liquids containing suspensions?

• crystallization

• decanting

• separating funnel

• centrifuging

Fine insoluble solid particles can be removed through which of the following process?

• crystallization

• decanting

• centrifuging

• separating funnel

Process quicker than filtration but not so effective is

• decanting

• centrifuging

• crystallization

• fractional distillation

Differential centrifugation relies on the differences in ______ of biological particles of different

• Size, density

• Sedimentation rate, sizes and density

• Size, structure

• Mass, size

Which of the following statements about the basic principle of sedimentation is False?

• The denser a biological structure is, the faster it sediments in a centrifugal field

• The more massive a biological particle is, the slower it moves in a centrifugal field

• The denser the buffer system is, the slower the particle will move in a centrifugal field

• The greater the centrifugal force is, the faster the particle sediments

Which of the following is/are the application of analytical centrifugation?

I. The determination of the purity of macromolecules.

II. The determination of the relative molecular masses of solutes in their native state.

III. The examination of changes in the molecular mass of supramolecular complexes.

IV. The detection of conformational changes.

• I only

• I and II only

• I, II and III only

• I, II, III and IV

Which of the following is/are appropriate care and maintenance of centrifuges?

I. Proper balancing of centrifuge tubes.

II. Avoid long time exposure of the rotors to alkaline solution and acidic buffers.

III. Cleaning centrifuges and rotors with coarse brushes and then wash them with distilled or de-ionized water after every run.

IV. For overnight storage, the rotors are left upside down and then positioned in a safe and dry place.

• I, II, III only

• II, III and IV only

• I, II, and IV only

• II only