MCQOPTIONS
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MCQOPTIONS
This section includes 128 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemical knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Write whether the following statements are true or false : (a) Three important characteristics in performance of biosensors are selectivity, sensitivity and stability (b) Activated sludge process is one of the most common anaerobic sewage treatment method (c) In a fermentor, impellors increase oxygen demand by producing high shear forces. (d) A pressure cycle is a type of air lift fermentor (e) Monoclonal antibodies are used extensively in diagnosis of haematopoietic cancers |
| A. | Only a |
| B. | b and c |
| C. | Only b and e |
| D. | a , c , d and e |
| E. | None of these |
| Answer» F. | |
| 2. |
Choose the correct completion of the following statement. A fermenter sterilisation in situ is less efficient than continuous heat sterilisation because |
| A. | it uses higher temperature for longer time |
| B. | it uses longer heating time during which heat is lost |
| C. | it uses larger volume and hence takes longer to cool the medium |
| D. | it uses steam as the heating source |
| Answer» C. it uses larger volume and hence takes longer to cool the medium | |
| 3. |
In large-scale fermentation, the preferred method of sterilizationsterilization is |
| A. | Chemicals |
| B. | Radiation |
| C. | Filtration |
| D. | Heat |
| Answer» E. | |
| 4. |
The kinetics of the disintegration of baker s yeast cells in a bead mill is described as dp/dt = K. (Pm P), where P is the concentration of protein released and Pm is the maximum protein concentration achievable. K is the first order rate constant and is 0.5 hr 1 for the system studied. The time required for the release of 90% of the intracellular proteins will be |
| A. | 10 hr |
| B. | 2 hr |
| C. | 4.6 hr |
| D. | None of these |
| Answer» D. None of these | |
| 5. |
Which of the following statements are true about bioreactors? P. Continuous bioreactors provide less degree of control and uniform product quality than batch bioreactors. Q. Batch bioreactors are ideally suited for reaction with substrate inhibition. R. Choice of a bioreactor is dictated by kinetic considerations. S. Fed batch bioreactors are also called semibatch bioreactors. |
| A. | P, Q |
| B. | Q, S |
| C. | R, S |
| D. | P, R |
| Answer» D. P, R | |
| 6. |
A bacterial culture with an approximate biomass composition of CH1.8O0.5N0.2 is grown aerobically on a defined medium containing glucose as the sole carbon source and ammonia being the nitrogen source. In this fermentation, biomass is formed with a yield coefficient of 0.35 gram dry cell weight per gram of glucose and acetate is producedwith a yield coefficient of 0.1 gram acetate per gram of glucose. The respiratory coefficient for the above culture will be |
| A. | 0.90 |
| B. | 0.95 |
| C. | 1.00 |
| D. | 1.05 |
| Answer» C. 1.00 | |
| 7. |
Match the bioreactor components in group 1 with the most appropriate function given in group 2 Group 1 Group 2 P. Marine type impeller 1. Recirculation of medium Q. Draft tube 2. Aeration of medium R. Diaphragm valve 3. Animal cell cultivation S. Sparger 4. Sterile operation |
| A. | P-4 , Q-2 , R-1 , S-3 |
| B. | P-3 , Q-1 , R-4 , S-2 |
| C. | P-3 , Q-4 , R-2 , S-1 |
| D. | P-2 , Q-1 , R-4 , S-3 |
| Answer» C. P-3 , Q-4 , R-2 , S-1 | |
| 8. |
Downstream processing of an industrial process yielded a highly purified bioactive protein. This protein was subjected to cleavage by trypsin. Chromatographic separation of products resulted in 4 peptides (P, Q, R, S) with the following amino acid sequencesP. phe-val-met-val-arg Q. ala-ala-try-gly-lys R. val-phe-met-ala-gly-lys S. phe-gly-try-ser-thr Chemical cleavage of the same protein with cyanogenbromide and chromatographic separation resulted in three peptides (i, ii, iii) with the following sequences (i) ala-gly-lys-phe-gly-try-ser-thr (ii) ala-ala-pry-gly-lys-phe-val-met (iii) val-arg-val-phe-met The order of the peptides that gives the primary structure of the original protein is |
| A. | P, Q, R, S |
| B. | Q, P, R, S |
| C. | Q, R, P, S |
| D. | R, Q, P, S |
| Answer» D. R, Q, P, S | |
| 9. |
Main functions of baffles in a bioreactor are P. to prevent a vortex Q. to increase aeration R. to reduce interfacial area of oxygen transfer S. to reduce aeration rate |
| A. | P, Q |
| B. | Q, R |
| C. | R, S |
| D. | P, S |
| Answer» B. Q, R | |
| 10. |
The specific growth rate ( ) of a microorganism in death phase is |
| A. | 0 (zero) |
| B. | |
| C. | |
| D. | less than zero |
| E. | greater than zero |
| Answer» B. | |
| 11. |
A bacterial culture having a specific oxygen uptake rate of 5 mmol O2 (g-DCW) 1 hr 1 is being grown aerobically in a fed-batch bioreactor. The maximum value of the volumetric oxygen transfer coefficient is 0.18s 1 for the stirred tank bioreactor and the critical dissolved oxygen concentration is 20% of the saturation concentration (8mg/ml). The maximum density to which the cells can be grown in the fed-batch process without the growth being limited by oxygen transfer, is approximately. |
| A. | 14 g/l |
| B. | 26 g/l |
| C. | 32 g/l |
| D. | 65 g/l |
| Answer» E. | |
| 12. |
During cultivation of microorganisms in a fermenter, various parameters are controlled by appropriate sensor (probe). Match each probe in group 1 with the appropriate response mechanism in group 2. Group 1 (Probe) Group 2 (Response) P. Thermistor 1. Activation of acid alkali pump Q. Oxygen electrode 2. Activation of vegetable oil pump R. Metal rod 3. Activation of hot cold water pump S. pH electrode 4. Increase/decrease in stirrer motor speed |
| A. | P-2, Q-3, R-1, S-4 |
| B. | P-l, Q-2, R-4, S-3 |
| C. | P-3, Q-2, R-4, S-1 |
| D. | P-3, Q-4, R-2, S-1 |
| Answer» E. | |
| 13. |
What will be the overall productivity of the system in kg year 1 m 3 ? |
| A. | 19250 |
| B. | 38.50 |
| C. | 3850 |
| D. | 77 |
| Answer» E. | |
| 14. |
Diauxic pattern of biomass growth is associated with (P) multiple lag phases (Q) sequential utilization of multiple substrates (R) simultaneous utilization of multiple substrates (S) absence of lag phase |
| A. | P, R |
| B. | P, Q |
| C. | R, S |
| D. | Q, S |
| Answer» C. R, S | |
| 15. |
Determine the correctness or otherwise of the following Assertion (a) and Reason (r): Assertion (a) : Bacterial growth is called synchronous when majority of the cells are in same stage of the bacterial cell cycle. Reason (r) : Synchronous culture can be obtained by growing bacteria in an enriched medium. |
| A. | Both (a) and (r) are true and (r) is the correct reason for (a) |
| B. | Both (a) and (r) are true but (r) is not the correct reason for (a) |
| C. | (a) is true but (r) is false |
| D. | (a) is false but (r) is true |
| Answer» D. (a) is false but (r) is true | |
| 16. |
If YX/S = 0.4 g / g for the above culture and steady state cell concentration in the bioreactor is 4 g/ L the resulting substrate concentration will be |
| A. | 2 g/L |
| B. | 8 g/L |
| C. | 4 g/L |
| D. | 6 g/L |
| Answer» B. 8 g/L | |
| 17. |
Thermal death of microorganisms in the liquid medium follows first order kinetics. If the initial cell concentration in the fermentation medium is 108 cells / ml and the final acceptable contamination level is 10 3 cells, for how long should 1m3 medium be treated at temperature of 120 (thermal deactivation rate constant = 0.23 / min) to achieve acceptable load? |
| A. | 48 min |
| B. | 11 min |
| C. | 110 min |
| D. | 20 min |
| Answer» D. 20 min | |
| 18. |
A T-flask is seeded with 105 anchorage-dependent cells. The available area of the T-flask is 25 cm2 and the volume of the medium is 25 ml. Assume that the cells are rectangles of size 5 m 2 m. If the cells grow to monolayer confluence after 50 h, the growth rate in number of cells/(cm2.h) is ____ 105 . |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 19. |
What would be the yield YX/S (Kg biomass/Kg substrate)? |
| A. | 0.562 |
| B. | 0.462 |
| C. | 0.362 |
| D. | 0.162 |
| Answer» B. 0.462 | |
| 20. |
Maximum specific growth rate ( max) of a microorganism is calculated by taking the (ln = loge, X = biomass, t = time) |
| A. | slope of ln X vs t of the growth cycle |
| B. | slope of ln X vs t during the exponential growth phase |
| C. | slope of X vs t |
| D. | slope of X vs t during the exponential phase of growth |
| Answer» C. slope of X vs t | |
| 21. |
Determine the correctness or otherwise of the following Assertion (A) and the Reason (R). Assertion : In synchronous culture, majority of the cells move to next phase of the cell cycle simultaneously. Reason : Synchronous culture could be obtained by starving cells for essential nutrient components. |
| A. | both (A) and (R) are true and (R) is the correct reason for (A) |
| B. | both (A) and (R) are true but (R) is not the correct reason for (A) |
| C. | (A) is true but (R) is false |
| D. | (A) is false but (R) is true |
| Answer» C. (A) is true but (R) is false | |
| 22. |
Structured William's model P. can describe the changes in intracellular components of the cell during growthQ. cannot describe the death phase of the cells R. can describe the variation of size of cells in the different phases of growth S. cannot describe the lag period of growth Which one of the following is correct? |
| A. | P, Q and S only |
| B. | P, Q and R only |
| C. | Q, R and S only |
| D. | P, R and S only |
| Answer» C. Q, R and S only | |
| 23. |
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 1h 1) after 3h of steady state operation will be ______ |
| A. | 9 |
| B. | 38 |
| C. | 18 |
| D. | 58 |
| Answer» D. 58 | |
| 24. |
Calculate the percentage sequence identity for the pairwise alignment given below._____ H E L L O Y E L L O W |
| A. | 33.5 to 44.7 |
| B. | 66.5 to 66.7 |
| C. | 22.5 to 33.7 |
| D. | 99.5 to 99.7 |
| Answer» C. 22.5 to 33.7 | |
| 25. |
In a well aerated and agitated microbial culture, the supply' of oxygen is equal to demand' (uptake) of the growing culture. The KLa for such a system will be (KLa = volumetric mass transfer coefficient, C* = dissolved oxygen concentration in liquid in equilibrium with gaseous oxygen,C = instantaneous value of dissolved oxygen concentration, r' = specific oxygen uptake rate per unit weight of cells, X = dry weight of the cells per unit volume) |
| A. | (r X)/ (C* C) |
| B. | (r)/ X(C* C) |
| C. | (C* C)/ (r X) |
| D. | (X)/ r(C* C) |
| Answer» B. (r)/ X(C* C) | |
| 26. |
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 (Yp/s). ______ |
| A. | 0.81 to 0.91 |
| B. | 0.27 to 0.31 |
| C. | 81 to 91 |
| D. | 0.91 to 0.98 |
| Answer» B. 0.27 to 0.31 | |
| 27. |
Match the microbial growth characteristics in Group I with the corresponding features in Group II. Group I P. Growth associated product formation Q. Non growth associated product formation R. Product inhibition S. Substrate inhibition Group II 1. Specific growth rate decreases with increasing product concentration 2. Specific product formation rate is constant 3. Specific product formation rate is proportional to specific growth rate4. Specific growth rate decreases with increasing substrate concentration |
| A. | P-1 , Q-2 , R-4 , S-3 |
| B. | P-3 , Q-2 , R-1 , S-4 |
| C. | P-2 , Q-1 , R-3 , S-4 |
| D. | P-2 , Q-3 , R-4 , S-1 |
| Answer» C. P-2 , Q-1 , R-3 , S-4 | |
| 28. |
Biomass is being produced in a continuous stirred tank bioreactor of 750 L capacity. The sterile feed containing 8 g.L 1 glucose as substrate was fed at a flow rate of 150 L.h 1. The microbial system follows Monod's model with m = 0.4 h 1, Ks = 1.5 g.L 1 and Yx/s = 0.5 g cell mass-g substrate 1. Determine the cell productivity (g.L 1.h 1) at steady state. |
| A. | 0.85 |
| B. | 0.65 |
| C. | 0.45 |
| D. | 0.25 |
| Answer» C. 0.45 | |
| 29. |
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 (Yx/s = 0.6 g cell/g substrate)_______ |
| A. | 36.7 to 46.9 |
| B. | 76.7 to 76.9 |
| C. | 86.7 to 96.9 |
| D. | None of the above |
| Answer» C. 86.7 to 96.9 | |
| 30. |
Wash out (as defined by D = max) of a continuous stirred tank fermenter is characterized by(X = biomass, S = substrate concentration in bioreactor, S0 = substrate concentration in feed, P = product concentration in bioreactor) |
| A. | X = 0, S = 0, P = 0 |
| B. | X = 0, S = S |
| C. | , P = 0 |
| D. | X = 0, S < 0, P = 0 |
| E. | X < 0, S < 0, P < 0 |
| Answer» C. , P = 0 | |
| 31. |
Samples of bacterial culture taken at 5 PM and then the next day at 5 AM were found to have 104 and 107 cells.mL 1, respectively. Assuming that both the samples were taken during the log phase of cell growth, the generation time of this bacterium will be _____ h. |
| A. | 1.2121 |
| B. | 12121 |
| C. | 12.121 |
| D. | 121.21 |
| Answer» B. 12121 | |
| 32. |
Decimal reduction time of bacterial spores is 23 min at 121 C and the death kinetics follow first order. One liter medium containing 105 spores per mL was sterilized for 10 min at 121 C in a batch sterilizer. The number of spores inthe medium after sterilization (assuming destruction of spores in heating and cooling period is negligible) will be ___________ 107. |
| A. | 3.6 to 3.8 |
| B. | 2.1 to 2.8 |
| C. | 6.3 to 8.3 |
| D. | None of the above |
| Answer» B. 2.1 to 2.8 | |
| 33. |
Saccharomyces cerevisiae is cultured in a chemostat (continuous fermentation) at a dilution rate of 0.5 h 1. The feed substrate concentration is 10 g.L 1. The biomass concentration in the chemostat at steady state will be _________g.L 1. Assumptions : Feed is sterile, maintenance is negligible and maximum biomass yield with respect to substrate is 0.4 (g biomass per g ethanol). Microbial growth kinetics is given by = m S Ks + Swhere is specific growth rate (h 1), m = 0.7 h 1, Ks = 0.3 g.L 1 and s is substrate concentration (g.L 1). |
| A. | 1.15 to 2.25 |
| B. | 9.65 to 10.75 |
| C. | 3.65 to 3.75 |
| D. | All of the above |
| Answer» D. All of the above | |
| 34. |
An enzyme converts substrate A to product B. At a given liquid feed stream of flow rate 25 L.min 1 and feed substrate concentration of 2 mol.L 1, the volume of continuous stirred tank reactor needed for 95% conversion willbe _____________ L. Given the rate equation : rA = 0.1 CA 1 + 0.5CAwhere rA is the rate of reaction in mol.L 1.min 1 and CA is the substrate concentration in mol.L 1 Assumptions : Enzyme concentration is contant and does not undergo any deactivation during the reaction. |
| A. | 1986.0 to 1989.0 |
| B. | 986.0 to 989.0 |
| C. | 2443.0 to 2544.0 |
| D. | 4986.0 to 4989.0 |
| Answer» E. | |
| 35. |
The empirical formula for biomass of an unknown organism is CH1.8 O0.5 N0.2. To grow this organism, ethanol (C2H5OH) and ammonia are used as carbon and nitrogen sources, respectively. Assume no product formation other than biomass. To produce 1 mole of biomass from 1 mole of ethanol, the number of moles of oxygen required will be ___________. |
| A. | 1.9 to 2.0 |
| B. | 5.9 to 7.2 |
| C. | 1.0 to 1.5 |
| D. | None of the above |
| Answer» B. 5.9 to 7.2 | |
| 36. |
Match the downstream processes in Group I with the products in Group II. Group I Group II P. Solvent extraction 1. Lactic acid Q. Protein-A linked affinity 2. Penicillin chromatography R. Extractive distillation 3. Monoclonal antibody S. Salting out 4. Lipase |
| A. | P-2 , Q-3 , R-1 , S-4 |
| B. | P-4 , Q-1 , R-2 , S-3 |
| C. | P-4 , Q-1 , R-3 , S-2 |
| D. | P-2 , Q-4 , R-1 , S-3 |
| Answer» B. P-4 , Q-1 , R-2 , S-3 | |
| 37. |
What is the holding period (min) at a k value of 3.36 min 1? |
| A. | 10.6 |
| B. | 9.5 |
| C. | 8.4 |
| D. | 7.2 |
| Answer» C. 8.4 | |
| 38. |
A fed batch culture was operated with intermittent addition of glucose solution at a flow rate of 200 ml h 1. The values of Ks, 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. _______ |
| A. | 0.1 |
| B. | 1 |
| C. | 0.01 |
| D. | 10 |
| Answer» B. 1 | |
| 39. |
Substrate consumption in lag phase of microbial growth is primarily used for P. turn over of the cell material Q. maintenance of intracellular pH R. motility S. increase in cell number |
| A. | P, Q and S only |
| B. | Q, R and S only |
| C. | P, Q and R only |
| D. | S only |
| Answer» D. S only | |
| 40. |
In an exponentially growing batch culture of Saccharomyces cerevisiae, the cell density is 20 gl 1 (DCW), the specific growth rate ( ) is 0.4h 1 and substrate uptake rate ( ) is 16 gl 1h 1. The cell yield coefficient Yx/s will be |
| A. | 0.32 |
| B. | 0.64 |
| C. | 0.80 |
| D. | 0.50 |
| Answer» E. | |
| 41. |
What is the value of holding? |
| A. | 31.96 |
| B. | 42.32 |
| C. | 52.43 |
| D. | 61.18 |
| Answer» B. 42.32 | |
| 42. |
In balanced growth phase of a cell P. all components of a cell grow at the same rate Q. specific growth determined by cell number or cell mass would be the same R. the growth rate is independent of substrate concentration S. the growth rate decreases with decreasing substrate concentration |
| A. | P, Q and S only |
| B. | Q, R and S only |
| C. | P, Q and R only |
| D. | P only |
| Answer» B. Q, R and S only | |
| 43. |
The feed flow rate required for the above bioconversion will be |
| A. | 50 lh |
| B. | 55 lh |
| C. | 137 lh |
| D. | 550 lh |
| E. | None of the above |
| Answer» F. | |
| 44. |
Which of the following events occur during the stationary phase of bacterial growth? P. Rise in cell number stops Q. Spore formation in some Gram-positive bacteria such as Bacillus subtilis R. Cell size increases in some Gram-negative bacteria such as Escherichia coli S. Growth rate of bacterial cells nearly equals their death rate T. Decrease in peptidoglycan crosslinking |
| A. | P, Q and S only |
| B. | P, S and T only |
| C. | Q, R and S only |
| D. | P, R and T only |
| Answer» B. P, S and T only | |
| 45. |
In a fed-batch culture, 200 g . L 1 glucose solution is added at a flow rate of 50 L . h 1. The initial culture volume (at quasi steady state) and the initial cell concentration are 600 L and 20 g . L 1, respectively. The yield coefficient (Yx/s) is 0.5 g cell mass . g substrate 1. The cell concentration (g . L 1) at quasi steady state at t = 8 h is |
| A. | 40 |
| B. | 52 |
| C. | 60 |
| D. | 68 |
| Answer» C. 60 | |
| 46. |
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 |
| Answer» C. Q and R only | |
| 47. |
Oxygen transfer was measured in a stirred tank bioreactor using dynamic method. The dissolved oxygen tension was found to be 80% air saturation under steady state conditions. The measured oxygen tensions at 7s and 17s were 55% and 68% air saturation, respectively. The volumetric mass transfer coefficient KLa is _____s 1 |
| A. | 7.339 |
| B. | 0.07339 |
| C. | 0.339 |
| D. | 7339 |
| Answer» C. 0.339 | |
| 48. |
A synchronous culture containing 1.8 105 monkey kidney cells was seeded into three identical flasks. The doubling time of these cells in 24 h. After 24 h, the cells from all the three flasks were pooled and dispensed equally into each well of three 6-well plates. The number of cells in each well will be ______ 104. |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» D. 3 | |
| 49. |
A bacterial culture (200 l containing 1.8 109 cells) was treated with an antibiotic Z (50 g per ml) for 4 h at 37 C. After this treatment, the culture was divided into two equal aliquots. Set A : 100 l was plated on Luria agar. Set B : 100 l was centrifuged, the cell pellet washed and plated on Luria agar.After incubating these two plates for 24 h at 37 C, Set A plate showed no colonies, whereas the Set B plate showed 0.9 109 cells. This experiment showed that the antibiotic Z is |
| A. | bacteriostatic |
| B. | bacteriocidal |
| C. | bacteriolytic |
| D. | apoptotic |
| Answer» B. bacteriocidal | |
| 50. |
Which one of the following is the most suitable type of impeller for mixing high viscosity (viscosity > 105 cP) fluids? |
| A. | Propeller |
| B. | Helical ribbon |
| C. | Paddle |
| D. | Flat blade turbine |
| Answer» C. Paddle | |