Questions and answers for exam Preparation

MCQs

Total Questions : 234 | Page 4 of 24 pages

Question 31. The enzyme β-galactosidase is also known as

lactase
EC3.2.1.23
both (a) and (b)
isomerase

Discuss Question

Answer: Option C. -> both (a) and (b)
Answer: (c).both (a) and (b)

Question 32. A cylindrical reactor fitted with Rushton Turbine has a liquid volume of 100,000 litres. It has an aspect ratio (the ratio of the channel height to the width) of 2:1. The diameter of the impeller should be approximately:

1.3 m
3.3 m
5.3 m
7.3 m

Discuss Question

Answer: Option A. -> 1.3 m
Answer: (a).1.3 m

Question 33. In the bubble boundary layer, oxygen concentration can be determined by measuring

the steady state oxygen concentration in a mixed aerated reactor before inoculation
the steady state oxygen concentration in a mixed aerated reactor after inoculation
the steady state oxygen concentration in the boundary layer using a micro-probe
volume of oxygen supplied

Discuss Question

Answer: Option A. -> the steady state oxygen concentration in a mixed aerated reactor before inoculation
Answer: (a).the steady state oxygen concentration in a mixed aerated reactor before inoculation

Question 34. To increase the oxygen transfer rate in a shake flask culture system, which of the following (s) is/are followed?

Liquid volume in the flask is reduced
Stirrer speed is increased
Baffled flasks are used
All of the above

Discuss Question

Answer: Option D. -> All of the above
Answer: (d).All of the above

Question 35. What is/are the major difference(s) between disc and turbine type stirrer?

Blades in disc type are projected out beyond the edge of disc while blades are curved one in turbine type
Turbine type requires 50 % less air than disc type for the same yield and energy consumption
Both (a) and (b)
Number of blades in the stirrer

Discuss Question

Answer: Option C. -> Both (a) and (b)
Answer: (c).Both (a) and (b)

Question 36. Impeller damage can be minimized by

using specially designed axial flow impellers
using radial flow impellers
using Intermig impellers
all of the above

Discuss Question

Answer: Option A. -> using specially designed axial flow impellers
Answer: (a).using specially designed axial flow impellers

Question 37. Larger propellers turn at the speed of

20 to 150 rpm
150 to 300 rpm
400 to 800 rpm
1150 rpm

Discuss Question

Answer: Option C. -> 400 to 800 rpm
Answer: (c).400 to 800 rpm

Question 38. A microbial population in a suspension culture will only be limited by oxygen availability if the dissolved oxygen

concentration is less than the critical concentration
concentration is greater than the critical concentration
levels are greater than the saturation concentration of oxygen
levels are equal to saturation oxygen level

Discuss Question

Answer: Option A. -> concentration is less than the critical concentration
Answer: (a).concentration is less than the critical concentration

Question 39. Which of the following model holds correct for the two-film theory? (where KL is the mass transfer coefficient, DAB diffusivity and Zf film thickness)

KL = DAB/Zf
KL = DAB
KL = Zf/DAB
KL = DAB.Zf

Discuss Question

Answer: Option A. -> KL = DAB/Zf
Answer: (a).KL = DAB/Zf

Question 40. A fermentation system has a KLa of 3 s¹ and a C0* of 5 ppm of O₂. If the bulk liquid is completely depleted of oxygen, then the oxygen transfer rate will be equal to