Immobilized Enzyme

Q1: Which of the following is taken as an assumption in the distributed model?

A The reaction occurs at every position and the kinetics of the reaction are of the same form as observed for free enzyme.

B Mass transfer through the immobilized enzyme occurs via molecular diffusion

C There is no mass transfer limitation at the outside surface of the spherical immobilized enzyme

D All of the above

ANS:D - All of the above

No answer description is available.

Q2: Which medium is used for the production of Penicillin using immobilized cells

A 1% peptone medium

B glucose medium

C Yeast extract medium

D LB broth

ANS:B - glucose medium

No answer description is available.

Q3: Commonly employed water insoluble supports for the covalent attachment of enzyme include

A acrylamide based polymers

B polypeptides

C dextran

D all of these

ANS:D - all of these

No answer description is available.

Q4: The immobilization technique involving physical method is

A covalent bond formation dependent

B non-covalent bond formation dependent

C both (a) and (b)

D ionic bond formation dependent

ANS:B - non-covalent bond formation dependent

No answer description is available.

Q5: Water insoluble enzymes can be prepared by using multifunctional agents that are bifunctional in nature and have

A low molecular weight

B high molecular weight

C high equivalent weight

D low reactivity

ANS:A - low molecular weight

Why we use low molecular weight bifunctional agent insted of single functional agent? Please explain.

Q6: During the enzymatic reaction of an immobilized enzyme, the rate of substrate transfer is

A equal to that of substrate consumption

B more than that of substrate consumption

C lesser than that of substrate consumption

D is nothing to do with the substrate consumption

ANS:A - equal to that of substrate consumption

Because no enzyme involved directly into reaction.

Q7: The covalent attachment of enzyme molecules is via

A nonessential amino acids residues to water insoluble, functional supports

B essential amino acids residues to water insoluble, functional supports

C nonessential amino acids residues to water soluble, functional supports

D essential amino acids residues to water soluble, functional supports

ANS:A - nonessential amino acids residues to water insoluble, functional supports

No answer description is available.

Q8: The support material for immobilization of cells of Bacillus subtilis is

A ion exchange resins

B gelatin

C Anthracite

D agarose and carbodiimide

ANS:D - agarose and carbodiimide

No answer description is available.

Q9: Damkohler number(NDa) is

A the ratio of the maximum reaction rate to the maximum mass transfer rate

B the ratio of the minimum reaction rate to the maximum mass transfer rate

C the ratio of the maximum reaction rate to the minimum mass transfer rate

D the ratio of the minimum reaction rate to the minimum mass transfer rate

ANS:A - the ratio of the maximum reaction rate to the maximum mass transfer rate

No answer description is available.

Q10: The immobilized enzyme produced by micro encapsulation technique provides

A an extremely large surface area

B smaller surface area

C high amount of solvent

D relatively smaller surface area

ANS:A - an extremely large surface area

No answer description is available.

Q11: Various techniques are available for determining the effective diffusivity of solute in gel. Thin disk method uses

A a diffusion cell with two compartments divided by a thin gel

B a diffusion cell with two compartments

C a diffusion cell with two compartments plus by a thin gel

D a diffusion cell with two compartments multiply by a thin gel

ANS:A - a diffusion cell with two compartments divided by a thin gel

No answer description is available.

Q12: The immobilized technique involving chemical method is

A covalent bond formation dependent

B non-covalent bond formation dependent

C both (a) and (b)

D ionic bond formation dependent

ANS:A - covalent bond formation dependent

No answer description is available.

Q13: To measure the extent to which the reaction rate is lowered because of resistance to mass transfer, the effectiveness factor of an immobilized enzyme, η can be defined as

A reaction rate/rate if not slowed by diffusion

B rate if not slowed by diffusion/ reaction rate

C actual reaction rate/ rate if not slowed by diffusion

D rate if not slowed by diffusion/ actual reaction rate

ANS:C - actual reaction rate/ rate if not slowed by diffusion

No answer description is available.

Q14: Which of the following is not a physical method of immobilization?

A Adsorption

B Entrapment

C Micro encapsulation

D None of these

ANS:D - None of these

Adsorption is chemical method.

Q15: Functional groups of the nonessential amino acid residues that are suitable for the immobilization process are

A free α-, β- or γ carb oxyl groups

B α or β amino groups

C phenyl, hydroxyl, sulfhydryl or imidazole groups

D all of the above

ANS:D - all of the above

No answer description is available.

Q16: If Damkohler number, NDa >>1, the reaction rate is much greater than the mass transfer rate and the overall reaction is controlled by the rate of mass transfer. In this case, the enzyme reaction can be described as (where Csb and Cs are the substrate concentration in bulk of solution and at the immobilized enzyme surface respectively. ks mass transfer coefficient, and a is the surface area of an immobilized enzyme particles)

A rp = ksa(Csb-Cs)

B rp = ksaCsb

C rp = ksaCs

D rp = ksa(Csb+Cs)

ANS:B - rp = ksaCsb

Please explain the answer in detail to understand.

Q17: Which of the following is the commonly employed adsorbents?

A Calcium carbonate

B Alumina

C Celluloses

D All of these

ANS:D - All of these

No answer description is available.

Q18: The intraparticle mass transfer resistance can affect the rate of enzyme reaction, if enzymes are immobilized by

A copolymerization or microencapsulation

B crosslinking using multifunctional reagents

C adsorption

D all of the above

ANS:A - copolymerization or microencapsulation

No answer description is available.

Q19: The effectiveness factor increases with the

A increase of diffusivity and decreased with the increase of particle size

B increase of diffusivity and increased with the increase of particle size

C decrease of diffusivity and decreased with the increase of particle size

D increase of diffusivity and decrease with the decrease of particle size

ANS:A - increase of diffusivity and decreased with the increase of particle size

No answer description is available.

Q20: Which of the following is not the correct answer?

A Immobilized enzyme may show selectively altered chemical properties

B Immobilized enzyme may show selectively altered physical properties

C Immobilized enzyme may simulate the realistic natural environment where the enzyme come from the cell

D None of the above

ANS:D - None of the above

No answer description is available.

Q21: For a steady state condition, the change of substrate concentration (dCs/dt) is

A zero

B 1

C >1

D <1

ANS:A - zero

No answer description is available.

Q22: Which is not the method for producing immobilized enzymes with multifunctional reagents?

A Enzymes are adsorbed on the surface active support followed by intermolecular cross linking

B Functional groups are introduced on the support to react co-valently with enzymes

C Enzymes are cross linked intermolecularly

D None of the above

ANS:D - None of the above

No answer description is available.

Q23: Which of the following is considered as a disadvantage to the adsorption method of immobilization?

A It is possible to separate and purify the enzymes while being immobilized

B The enzymes are not usually deactivated by adsorption

C The adsorption is a reversible process

D State of immobilization is very sensitive to solution pH, ionic strength and temperature

ANS:D - State of immobilization is very sensitive to solution pH, ionic strength and temperature

No answer description is available.

Q24: For glucose isomerization by immobilized enzyme, the reactor generally used is

A CSTR

B plug flow

C packed bed

D fluidized bed

ANS:C - packed bed

No answer description is available.

Q25: The most commonly employed cross-linked polymer is the

A polyacrylamide gel

B collagen

C celluloses

D cation exchange resin

ANS:A - polyacrylamide gel

No answer description is available.



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