BE

Question 1

A biological agent that accelerates the rate of chemical reaction but whose quantity or
concentration and chemical identity remains theoretically unchanged at the end of reaction.

Answer 1

Enzyme

Question 2

If the half-life of the enzyme-catalyzed dimerization of proflavine is t1/2=0.001/[proflavin]0, then the most feasible chemical equation that will represent the
equation is:

Answer 2

2(proflavin) –k(Proflavin)2

Question 3

A widely accepted model for enzyme-substrate complex formation which suggests that
enzymes are flexible structures in which the active site continually reshapes by its
interaction with the substrate until the time the substrate is completely bound to it.

Answer 3

Induced-fit Model

Question 4

In enzyme-catalyzed reactions, the molecules acted upon by the enzymes (i.e., reactant
molecules) are called

Answer 4

Substrate

Question 5

Michaelis-Menten model for enzyme kinetics suggests that formation of stable
enzyme-substrate complex is favored when

Answer 5

KM is low

Question 6

Turnover number is the number of _______ that can be covered per unit time per
active site on the enzyme.

Answer 6

Substrate molecules

Question 7

Which of the following is false according to the Michaelis-Menten kinetics?

Answer 7

The Michaelis-Menten constant KM is proportional to the enzyme concentration within the range of the enzyme tested.

Question 8

A nonprotein compound which combines with an otherwise inactive protein (apoenzyme) to give a catalytically active complex.

Answer 8

Cofactor

Question 9

Any molecule that reduces the rate of an enzyme reaction is a/an

Answer 9

Inhibitor

Question 10

In ______, the inhibitor has some degree of similarity with the substrate.

Answer 10

Competitive inhibition

Question 11

In _____, the inhibitor does not affect the value of Vmax but affects the value of KM.

Answer 11

Competitive Inhibition

Question 12

Uncompetitive inhibition _____ Vmax and _____ KM.

Answer 12

Decreases, decreases

Question 13

Enzymes which have more than 1 binding site.

Answer 13

Allosteric enzymes

Question 14

Confinement of enzyme in a phase (matrix or support) over which the substrate is
passed and converted to products (carrier-binding method)

Answer 14

Immobilization

Question 15

The following are types of immobilization except:
A. Physical
B. Chemical
C. Surface Immobilization
D. Entrapment
E. All are immobilization techniques

Answer 15

All are immobilization techniques

Question 16

The kinetics of cell death is usually

Answer 16

First Order

Question 17

In this type of reactor, the liquid volume is kept constant by setting the outlet flow
rate equal to the inlet flow rate. However, the inlet flow rate is adjusted to keep the
biomass concentration constant.

Answer 17

Turbidostat

Question 18

Aspergillus niger is used to produce gluconic acid. Product synthesis is monitored in a
fermenter; gluconic acid concentration is measured as a function of time for the first 39h
of culture. Determine the order of reaction

Answer 18

First Order

Question 19

Aspergillus niger is used to produce gluconic acid. Product synthesis is monitored in a
fermenter; gluconic acid concentration is measured as a function of time for the first 39h
of culture. Determine the rate constant

Answer 19

0.10 h^-1

Question 20

Aspergillus niger is used to produce gluconic acid. Product synthesis is monitored in a
fermenter; gluconic acid concentration is measured as a function of time for the first 39h
of culture. Estimate the product concentration after 20h.

Answer 20

29.49 g/L

Question 21

Amylglucosidase from Endomycopsis bispora is immobilized in a very small
polyacrylamide gel beads. The activities of immobilized and soluble enzymes are
compared at 80OC. Initial rate data are measured at a fixed substrate concentration with
the following results. What is the half-life for the soluble enzyme?

Answer 21

23.46 min

Question 22

Amylglucosidase from Endomycopsis bispora is immobilized in a very small
polyacrylamide gel beads. The activities of immobilized and soluble enzymes are
compared at 80OC. Initial rate data are measured at a fixed substrate concentration with
the following results. What is the half-life for the immobilized enzyme?

Answer 22

137 min

Question 23

A substrate is converted to a product by the catalytic action of an enzyme. Assume that
the Michaelis-Menten kinetics parameters for this enzyme are: KM=0.04 mol/L and
Vmax=12.5 mol/L-min. What should be the size of a steady state CSTR to convert 98% of the incoming
substrate (CSO=15 mol/L) with a flow rate of 10 L/h?

Answer 23

0.22 L

Question 24

If a PFR of size equal to that of the CSTR in item 23 is used, what would be the
substrate conversion?

Answer 24

0.999

Question 25

Eadie (1942) measured the initial reaction rate of hydrolysis of acetylcholine (substrate) by dog serum (source of enzyme) in the absence and presence of prostigmine (inhibitor), 1.5x10-7 mol/L and obtained the following data. What type of inhibitor is prostigmine?

Answer 25

Uncompetitive

Question 26

Eadie (1942) measured the initial reaction rate of hydrolysis of acetylcholine (substrate) by dog serum (source of enzyme) in the absence and presence of prostigmine (inhibitor), 1.5x10-7 mol/L and obtained the following data. What is the Michaelis-Menten constant using the Langmuir plot?

Answer 26

0.001h

Question 27

Zymoonas mobilis is used to convert glucose to ethanol in a batch fermenter under anaerobic conditions. The yield of biomass from substrate is 0.06 g/g; YPX=7.7 g/g. The maintenance coefficient is 2.2 g/g-h; the specific rate of product formation due to maintenance is 1.1/h. The maximum specific growth rate of Z. mobilis is approximately 0.3/h. Five grams of bacteria are inoculated into 50 L of medium containing 12 g/L glucose. Determine the batch culture time required to produce 10g of biomass

Answer 27

3.7h

Question 28

Zymoonas mobilis is used to convert glucose to ethanol in a batch fermenter under anaerobic conditions. The yield of biomass from substrate is 0.06 g/g; YPX=7.7 g/g. The maintenance coefficient is 2.2 g/g-h; the specific rate of product formation due to maintenance is 1.1/h. The maximum specific growth rate of Z. mobilis is approximately 0.3/h. Five grams of bacteria are inoculated into 50 L of medium containing 12 g/L glucose. Determine the batch culture time required to achieve 90% substrate conversion

Answer 28

5.7h

Question 28

Zymoonas mobilis is used to convert glucose to ethanol in a batch fermenter under anaerobic conditions. The yield of biomass from substrate is 0.06 g/g; YPX=7.7 g/g. The maintenance coefficient is 2.2 g/g-h; the specific rate of product formation due to maintenance is 1.1/h. The maximum specific growth rate of Z. mobilis is approximately 0.3/h. Five grams of bacteria are inoculated into 50 L of medium containing 12 g/L glucose. Determine the batch culture time required to produce 100g ethanol

Answer 28

3.4 h

Question 29

Which of the following statements is false?

Answer 29

Harvested fermentation broths are not susceptible to contamination.