DSP ONLINE BITS 4 UNIT V

UNIT V

Precipitation with salts, organic solvent and polymers

1.Which of the following changes is made use of in precipitation?

chemical change.

2. Precipitation serves to achieve separation by which of the following process?

conversion of solutes to solids.

3. Protein precipitation may be induced by which of the following methods?

(i)Addition of neutral salts (ii) solvent addition (iii) charged metal ion addition

(i), (ii) and (iii)

4. which of the following methods is used to separate the precipitated solids from liquids in precipitation? Centrifugation.

5. Proteins remain in the solution when

It is thermodynamically more favourable to be surrounded by solvent.

6. What is isoelectric pH? pH at which there is no charge on the molecule

7. The plot of solubility vs pH is a is V shaped curve

8. In salting out, the added slats remove water from the hydrated protein leaving the Hydrophobic.region free to combine inter-molecularl

9. In salting out at high salt concentration, the hydrophobic contribution exceeds Electrostatic contribution thus resulting in salting out.

10. According to MElander and Hovarth’s result, the semi log plot between solubility (on y axis) and ionic strength(on x axis) for protein at high electrostatic contribution is Linear

11. The intercept of the linear salting out portion of a plot between ln(w/w₀ ) vs m gives Debye constant (w is solubility in salt solution of molarity m and w₀ is solubility in pure water)

12. For a protein, a plot of logarithm of solubility vs ionic strength at high molarity the slope k(salting out constant) depends on which of the following factors? (i) surface hydrophobicity (ii) dipole moment (iii) molal surface tension increment. (i), (ii) and (iii)

13. In case of addition of organic solvent, the solvent property affected is dielectric constant.

14. Upon the addition of organic solvent, the hydrophobic areas of the protein tend to become more ________,but the net result is __________ in solubility.

More soluble, decrease.

15. There is a decrease in required organic solvent concentration when precipitation is carried out at close to isoelectric point because precipitation is dependent on Electrostatic forces

16. In Schubert and Finn plot between logarithm of solubility versus solvent concentration, the linear behavior is disrupted when conformational changes accompany solvent addition.

17. The layer of charge adjoining the protein molecule in a solution is known as Stern layer

18. According to DLVO theory, the attractive and repulsive forces between colloidal particles can be Divided

19. The correct order in which the cations decrease the K value while salting out is given by

Al³⁺>Ca²⁺

20. According to Hofmeister series, the effectiveness of neutral salts in salting out decreases in order Citrate>phosphate>Sulphate

Aqueous 2 phase extraction and In situ product removal

21. In phase diagram of aqueous 2 phase extraction, the mixture separates along Tie line.

22. In aqueous 2 phase extraction, the critical point is represented by One

point on the binodal curve.

23. In aqueous 2 phase extraction, the value of partition coefficient at the critical point is One

24. In aqueous 2 phase extraction, the partition coefficient is defined asRatio of concentration of top and bottom phase.

25. An extraction system is usually designed such that the wanted protein partitions predominantly to the Top.phase.

26. The separation power of an extraction system is characterized by which of the following factors? (i)yield (ii) separation factor (iii) partition coefficient(i), (ii) and (iii).

27.The yield (Y) in top phase of extraction process is defined as (given n is molar quantity of desired protein) Y=nt/(nt+nb)

28.The separation factor(G) is related to the volume ratio(R) and partition coefficient (K) by

G=K.R

29. The partition coefficient depends on which of the following factors?

i. Molecular weight of the polymer used. (ii)Concentration of protein when it is much lower than the concentration of phase forming polymer. (iii) temperature(i) and (iii).

30. The partition coefficient can be Increased.by increasing the molecular weight of bottom phase forming polymer.

31. The partition coefficient can be Increased.by lowering the molecular weight of top phase forming polymer.

32. Change in pH aids in extraction of proteins by

(i) affecting the ionization of the side chains. (ii) Affecting the charge and hydrophobic balance on the surface (iii) altering the K value by ionizing the weak acids. (i), (ii) and (iii)

33. Phase separation will occur if the Gibbs free energy of mixture of two phases becomes energetically More favorableGibbs free energy of single phase.

34. In affinity extraction, which of the following can be used as ligands for proteins?

(i) Cofactors (ii) inhibitors (iii) protein itself(i) and (ii).

35. In detergent based extraction system, Increase in turbidity acts as an indicator of phase separation

36. The temperature at which there is an increase in turbidity for detergent based extraction system is called Cloud point

37. Which property among the following can be seen as a difference between aqueous 2 phase systems and solvent water system.Very low interfacial tension.

38. Which process among the following can be used to separate protein from polymer phases?

(i) centrifugation (ii) adsorption (iii) ultrafilteration(i), (ii) and (iii)

39. In a detergent based extraction system, the detergent interacts preferably with

hydrophobic part of protein

40. In continuous extraction process, Counter current extraction method is more profitable.

Integrated Bioprocess

1.Integrated bioprocesses have been developed to ________ yield and _________ of production of low and high molecular weight molecules

optimize , cost-effectiveness

2. Low molecular weight products are removed from the cultivation medium with in in situ extraction

3. The two most promising adsorptive techniques for direct product recovery from crude feedstocks are ___________ and ________ both a and

4.Expand EBA expanded bed adsorption

5. Expand HGMFhigh gradient magnetic fishing

6. The best example for the integrated bioprocess isEBA

7. Integrated bioprocess has been developed suitable for production of recombinant peptides using a gene multimerization strategy and site-specific cleavage of the resulting gene product.

8. Integration of cell separation and protein isolation from mammalian cell cultures was demonstrated using a membrane wit lysine h as an affinity ligand combined with a rotating disc device to prevent membrane fouling.

9. Extraction of proteins from crude feedstocks is another approach combining solid/liquid separation, product concentration and a modest purification in one step

10. The main advantage of integrated bioprocess system is reduces the cost of production