Bioreaction Engineering - Fundamentals of Biological Engineering - Biotechnology Previous Year Questions

1

2013 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2013

The catalytic efficiency for an enzyme is defined as

A

\(k_{cat}\)

B

\(\frac{V_{max}}{k_{cat}}\)

C

\(\frac{k_{cat}}{K_m}\)

D

\(\frac{k_{cat}}{V_{max}}\)

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2

2013 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2013

A chemostat is operated at a dilution rate of \(0.6 h^{-1}\). At steady state, the biomass concentration in the exit stream was found to be \(30 g l^{-1}\). The biomass productivity (\(g l^{-1} h^{-1}\)) after 3h of steady state operation will be ________

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3

2013 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2013

In a batch culture, the specific rate of substrate utilization is \(0.25 g (g cell mass)^{-1} h^{-1}\) and specific rate of product formation is \(0.215 g (g cell mass)^{-1} h^{-1}\). Calculate the yield of product from the substrate(\(Y_{p/s}\)). ________

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4

2013 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2013

The activity of an enzyme was measured by varying the concentration of the substrate (S) in the presence of three different concentrations of inhibitor (I) 0, 2 and 4 mM. The double reciprocal plot given below suggests that the inhibitor (I) exhibits

A

substrate inhibition

B

uncompetitive inhibition

C

mixed inhibition

D

competitive inhibition

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5

2013 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2013

The maximum cell concentration (g l^-1) expected in a bioreactor with initial cell concentration of 1.75 g l^-1 and an initial glucose concentration of 125 g l^-1 is (Y_X/S = 0.6 g cell/g substrate) ________

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6

2013 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2013

A fed batch culture was operated with intermittent addition of glucose solution at a flow rate of 200 ml h^-1. The values of K_s, μ_m and D are 0.3 g l^-1, 0.4 h^-1 and 0.1 h^-1, respectively. Determine the concentration of growth limiting substrate (gl^-1) in the reactor at quasi-steady state. ________

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7

2013 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2013

The number of ligand binding sites present on receptors R1 and R3, respectively are

A

1 and 4

B

1 and 1

C

4 and 1

D

2 and 2

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8

2013 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2013

Which one of the receptors has the highest affinity for the ligand?

A

R1

B

R2

C

R3

D

R4

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9

2013 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2013

What is the holding period (min) at a k value of 3.36min^-1?

A

10.6

B

9.5

C

8.4

D

7.2

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10

2014 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2014

The unit for specific substrate consumption rate in a growing culture is

A

\(\frac{g}{L.h} \)

B

\(\frac{g}{h} \)

C

\(\frac{g}{g.h} \)

D

\(\frac{g.moles}{L.h} \)

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11

2014 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2014

The most plausible explanation for a sudden increase of the respiratory quotient (RQ) of a microbial culture is that

A

cells are dying

B

yield of biomass is increasing

C

the fermentation rate is increasing relative to respiration rate

D

the maintenance rate is decreasing

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12

2014 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2014

The degree of reduction of ethanol is ____

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13

2014 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2014

Which of the following essential element(s) is/are required as major supplement to enhance the bioremediation of oil spills by the resident bacteria?

A

Sulfur

B

Nitrogen and phosphorus

C

Iron

D

Carbon

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14

2014 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2014

Consider a continuous culture provided with a sterile feed containing 10 mM glucose. The steady state cell density and substrate concentration at three different dilution rates are given in the table below.

Dilution rate (h⁻¹)	Cell density (g L⁻¹)	Substrate concentration (mM)
0.05	0.248	0.067
0.5	0.208	1.667
5	0	10

The maximum specific growth rate \(\mu_m\) (in h⁻¹), will be ____.

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15

2016 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2016

Which one of the following statements is NOT true?

A

In competitive inhibition, substrate and inhibitor compete for the same active site of an enzyme

B

Addition of a large amount of substrate to an enzyme cannot overcome uncompetitive inhibition

C

A transition state analogue in enzyme catalyzed reaction increases the rate of product formation

D

In non-competitive inhibition, K_m of an enzyme for its substrate remains constant as the concentration of the inhibitor increases

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16

2016 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2016

Prandtl number is the ratio of

A

thermal diffusivity to momentum diffusivity

B

mass diffusivity to momentum diffusivity

C

momentum diffusivity to thermal diffusivity

D

thermal diffusivity to mass diffusivity

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17

2016 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2016

Fed batch cultivation is suitable for which of the following?
P. Processes with substrate inhibition
Q. Processes with product inhibition
R. High cell density cultivation

A

P and Q only

B

P and R only

C

Q and R only

D

P, Q and R

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18

2016 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2016

The equilibrium potential of a biological membrane for Na⁺ is 55 mV at 37 ^oC. Concentration of Na⁺ inside the cell is 20 mM. Assuming the membrane is permeable to Na⁺ only, the Na⁺ concentration outside the membrane will be ______ mM.
(Faraday constant: 23062 cal.V^-1.mol^-1, Gas constant: 1.98 cal.mol^-1.K^-1)

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19

2016 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2016

In an assay of the type II dehydrogenase of molecular mass 18 kDa, it is found that the V_max of the enzyme is 0.0134 μmol·min^-1 when 1.8 μg enzyme is added to the assay mixture. If the K_m for the substrate is 25 μM, the k_cat/K_m ratio will be __________×10⁵ M^-1·s^-1.

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20

2016 · Biotechnology · Fundamentals of Biological Engineering · Bioreaction Engineering

Biotechnology (BT) 2016

The activity of lactate dehydrogenase can be measured by monitoring the following reaction:
Pyruvate + NADH → Lactate + NAD⁺
The molar extinction coefficient of NADH at 340 nm is 6220 M^-1 cm^-1. NAD⁺ does not absorb at this wavelength. In an assay, 25 μL of a sample of enzyme (containing 5 μg protein per mL) was added to a mixture of pyruvate and NADH to give a total volume of 3 mL in a cuvette of 1 cm pathlength. The rate of decrease in absorbance at 340 nm was 0.14 min^-1. The specific activity of the enzyme will be __________ μmol·min^-1·mg^-1.

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