GATE BT year:2024 PYQs & Answers — Page 6

Questions 51–60 of 65. Imported answers require independent review unless marked reviewed.

Which of the following conditions induce(s) the expression of β-galactosidase gene in the lac operon?

Your answerSelect all correct options. You can choose more than one.

Absence of glucose

Absence of lactose

Presence of glucose

Presence of lactose

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Which of the following factors can affect the growth of a microbial culture in a batch cultivation process?

Your answerSelect all correct options. You can choose more than one.

pH of the medium

Osmolarity of the medium

Substrate concentration in the medium

Substrate feed rate

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Under complete cell washout condition in a chemostat with sterile feed, which of the following statements is/are correct?

Your answerSelect all correct options. You can choose more than one.

Biomass concentration in the reactor is maximum

Substrate concentration in the exit stream is less than that in the inlet stream

Substrate concentration in the exit stream is equal to that in the inlet stream

Substrate concentration in the exit stream is zero

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Fermentation medium is cooled from 121 °C to 30 °C in a double pipe heat exchanger. If cold water is flowing in the counter-current direction and is heated from 10 °C to 70 °C, then the Log-Mean Temperature Difference (LMTD) is ______ °C (rounded off to the nearest integer).

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Aspergillus niger is grown in a 10,000 L stirred batch bioreactor under aerated conditions to produce citric acid. At steady state oxygen transfer conditions, the specific oxygen uptake rate of the organism and the volumetric mass transfer coefficient are

and 60 min

, respectively.

If the oxygen solubility is

kg m

under the operating conditions, based only on oxygen dynamics, the maximum possible cell concentration is ______ kg m

(Answer in integer).

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Ethanol is produced in a 10,000 L stirred bioreactor using an impeller of diameter 1 m. The density and viscosity of fermentation broth are 1000 kg m

and 1 cp, respectively. The data relating the Power number and Impeller Reynolds number is given below:

| Reynolds number | 1-5 | 5-500 | > 10

| | Power number | 70 | 10 | 5 |

Using the above data, the power required for the stirrer to operate at 300 rpm is ______ kW (Answer in integer).

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The free energy change of ATP hydrolysis at 25 °C is -32.2 kJ mol

. The free energy change for hydrolysis of α-glycerophosphate to glycerol is -8.2 kJ mol

at 25 °C. Using the above information, the free energy change for the formation of α-glycerophosphate from glycerol and ATP is ______ kJ mol

(Answer in integer).

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E. coli is inoculated in a shake flask containing nutrient rich medium. The initial number of viable cells in the medium is 10

. After few hours, the number of viable cells is 10

. Assuming cell divides by binary fission, the number of generations that have taken place is ______ (rounded off to the nearest integer).

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A fermentor is filled with medium at a rate of 1 L min

. A leak develops at the bottom of the fermentor when the medium in the fermentor reaches 200 L. The rate of medium leakage is

L min

, where ‘t’ is the time at which the leak begins.

The volume of medium in the fermentor after 10 min of leakage is ______ L (Answer in integer).

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A fed batch process is running at quasi-steady state with respect to substrate and biomass concentration. At 2 h, the culture volume is 500 L with a constant sterile inlet feed at 50 L h

of glucose. The culture kinetic parameters

and

are 0.2 h

and 0.1 g L

, respectively.

The substrate concentration in the reactor will be ______ g L

(rounded off to one decimal place).

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GATE BT year:2024 PYQs

Question 51

Question 52

Question 53

Question 54

Question 55

Question 56

Question 57

Question 58

Question 59

Question 60