Questions and answers for exam Preparation

MCQs

Total Questions : 114 | Page 2 of 12 pages

Question 11. Which of the statement is true for continuous reactor at steady state?

The rates of biomass, substrate and product concentrations are zero
Biomass, substrate and product concentrations are zero
Biomass, substrate and product concentrations do not change with time
Biomass, substrate and product concentrations change with time

Discuss Question

Answer: Option C. -> Biomass, substrate and product concentrations do not change with time
Answer: (c).Biomass, substrate and product concentrations do not change with time

Question 12. A continuous bioreactor in which only the flow rate is used to control the rate of cell or product productivity is called

turbidostat
chemostat
level stat
pH

Discuss Question

Answer: Option B. -> chemostat
Answer: (b).chemostat

Question 13. In aerobic yeast fermentation for production of citric acid from alkanes using a fed-batch culture, why alkanes are slowly fed to the yeast?

Citric acid is toxic to the cells
Alkanes cause foaming
Fast addition of alkanes will inhibit the cells and reduce oxygen transfer rates
Fast addition of alkanes will cause the cells to grow too quickly

Discuss Question

Answer: Option C. -> Fast addition of alkanes will inhibit the cells and reduce oxygen transfer rates
Answer: (c).Fast addition of alkanes will inhibit the cells and reduce oxygen transfer rates

Question 14. Saccharomyces cerevisiae is being grown in a chemostat converts glucose to biomass, ethanol, glycerol and carbon dioxide. At steady state, the concentration of glucose, biomass, ethanol and glycerol will

decrease with time
increase with time
be constant
change randomly with time

Discuss Question

Answer: Option C. -> be constant
Answer: (c).be constant

Question 15. For organisms growing in a chemostat, the specific growth rate

cannot be determined
can be determined from the dilution rate
equals to the maximum specific growth rate of the culture
none of the above

Discuss Question

Answer: Option B. -> can be determined from the dilution rate
Answer: (b).can be determined from the dilution rate

Question 16. Formation of end product by Lactococcus lactis will become non-growth associated as lactic acid accumulates because

cells will redirect ATP to anabolism
cells will redirect NAD+ to anabolism
cells will redirect ATP to facilitate the diffusion of lactic acid and H+ out of the cells
cells will redirect ATP to the active transport of lactic acid and H+ out of the cells

Discuss Question

Answer: Option D. -> cells will redirect ATP to the active transport of lactic acid and H+ out of the cells
Answer: (d).cells will redirect ATP to the active transport of lactic acid and H+ out of the cells

Question 17. Which of the following would not be subjected to the "glucose effect"?

Aspergillus fumigatus
Saccharomyces cerevisiae
Escherichia coli
Aspergillus niger

Discuss Question

Answer: Option C. -> Escherichia coli
Answer: (c).Escherichia coli

Question 18. Mixing in an anaerobic sludge blanket reactor is due to

rapid change in water temperatures throughout the reactor
release of gases by the microbial populations
swimming of microbes
none of the above

Discuss Question

Answer: Option B. -> release of gases by the microbial populations
Answer: (b).release of gases by the microbial populations

Question 19. Immobilized cell reactors for wastewater treatment have the advantage of having/being

higher cell concentration
more stable and prevent washout
higher dilution rate before the cells washout
all of the above

Discuss Question

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

Question 20. In batch culture, protogon is produced from peptone during the stationary phase with a yield of 0.4 protogon mg per g of peptone. If it is to be produced in a chemostat at a dilution rate of 0.5 h¹ from a medium containing 10 g.l¹ of peptone, then the rate of protogon synthesis would be