Interview MCQ Set 1
1. The portion of the growth curve where a rapid growth of bacteria is observed is known as ____________
a) Lag phase
b) Logarithmic phase
c) Stationary phase
d) Decline phase
Answer: b [Reason:] A typical growth curve has four regions. An initial period of no growth known as lag phase, followed by rapid growth known as logarithmic phase. No growth is observed in stationary phase and death phase.
2. The growth of bacterial population follows a geometric progression.
Answer: a [Reason:] The bacteria show growth by following binary fission as means of reproduction.
Thus, if we start with a single bacterium, the increase in population is by geometric progression.
3. In the growth equation: n= 3.3 (log10 N – log10 No ), n stands for____________
a) total population
b) initial population
c) number of generations
d) growth constant
Answer: c [Reason:] In the above formula, n stands for the number of generations that have taken place after the growth.
4. Lag phase is also known as ___________
a) period of initial adjustment
b) transitional period
c) generation time
d) period of rapid growth
Answer: a [Reason:] In the lag phase, the bacteria maybe deficient in enzymes or coenzymes which must first be synthesized and thus time is required for adjustments in the physical environment. So it is also known as period of initial adjustment.
5. The generation time for E.coli is ________
a) 20 minutes
b) 35 minutes
c) 2 minutes
d) 13 minutes
Answer: a [Reason:] The generation time for E.coli at a temperature of 37 degree Celsius lies in the range of 15-20 minutes generally.
6. During exponential phase, growth rate is _______
a) same as generation time
b) reciprocal of generation time
c) time required for population to double
d) rate of doubling population
Answer: b [Reason:] During exponential growth, the growth rate (R) i.e., the number of generations per hour, is the reciprocal of the generation time g. Growth rate is the slope of the straight line obtained when the log number of cells is plotted against time.
7. In which of the following phase secondary metabolites are produced during growth?
a) Lag phase
b) Log/Exponential phase
c) Stationary phase
d) Death phase
Answer: c [Reason:] During the stationary phase, there is complete utilization of the nutrients present in media and thus produce secondary metabolites which are then used in different industries.
8. Which phase shows reproduction rate equal to the equivalent death rate?
a) Log phase
b) Stationary phase
c) Death phase
d) Lag phase
Answer: b [Reason:] In stationary phase there is a complete cessation of division and thus the reproduction rate is balanced by an equivalent death rate.
9. Which of the following is used to grow bacterial culture continuously?
Answer: a [Reason:] Chemostat is used for continuous cultivation. This system depends on the fact that the concentration of an essential nutrient within the culture vessel will control the growth rate of the cells.
10. The average size of the cells in the exponential phase is ___________
a) larger than the initial size
b) smaller than the initial size
c) equal to the initial size
d) maybe smaller or larger than the initial size
Answer: b [Reason:] During the exponential phase, the cells divide steadily at a constant rate and thus give a straight line. So the average size of cells goes on decreasing than the initial size due to binary fission.
Interview MCQ Set 2
1. Which of the following is not a characteristic of a chemotherapeutic agent?
a) low toxicity for host cells
b) high toxicity for the parasites
c) less penetrating power
d) does not affect the host’s natural defense mechanism
Answer: c [Reason:] A chemotherapeutic agent must be able to come in contact with the parasite by penetrating the cells and tissues of the host in effective concentrations.
2. Phenol is considered as a chemotherapeutic agent.
Answer: b [Reason:] Antiseptics and germicides such as phenol,coal-tar derivatives and many mercurial compounds are unsatisfactory as chemotherapeutic agents as they do not show selective toxicity for the parasite.
3. Which was the first disease for which a chemotherapeutic agent was used?
c) Small pox
Answer: a [Reason:] Syphilis is the first known disease for which a chemotherapeutic agent was used. An arsenical compound known as Salvarsan was synthesized by Paul Ehrlich in 1910 to treat this disease.
4. Sulfanilamide was synthesized by which of the following research scientists?
Answer: b [Reason:] Domagk showed the therapeutic value of a group of compounds known as the sulfonamides and Sulfanilamide was the first compound in this group to be synthesized by Gelmo in 1910.
5. Sulfonamides and arsphenamine are similar in their specificity for a special group of organism.
Answer: b [Reason:] Sulfonamides are not specific for a special group of organisms, as arsphenamine is for Treponema, but are effective against a large variety of pathogenic organisms.
6. Which of the following chemothearpeutic agent is extensively used because of their antibacterial effectiveness in a wide range of bacterial infections?
Answer: d [Reason:] Sulfadiazine and sulfamerazine are extensively used because of their antibacterial effectiveness in a wide range of bacterial infections and because they are least likely to produce toxic reactions in the patient.
7. The antibiotic penicillin was discovered by which of the following researchers?
a) Emmerich and Low
b) Gratia and Dath
c) Alexander Flemming
Answer: c [Reason:] Alexander Flemming identified the famous antibiotic penicillin obtained from the mold Penicillium sp.
8. Which of the following antibiotic is not involved in inhibition of specific enzyme systems?
Answer: c [Reason:] The sulphonamides have their antibacterial attack directed towards a specific essential enzyme.Their structure is related to p-aminobenzoic acid (PABA) which is a precursor to their synthesis of the essential coenzyme tetrahydrofolic acid (THFA).
Interview MCQ Set 3
1. Which of the following microorganism produces dextran?
a) Bacillus polymyxa
b) Bacillus thuringiensis
c) Leuconostoc mesenteroides
d) Streptomyces olivaceus
Answer: c [Reason:] Leuconostoc mesenteroides is the producer organism for dextran which acts as a stabilizer in food products and as a blood plasma substitute.
2. Which of the following carbohydrates are mainly present in whey?
Answer: b [Reason:] Whey represents a satisfactory medium for the growth of certain bacteria, since it contains lactose, nitrogenous substances including vitamins, and salts.
3. Lactobacillus bulgaricus is a homofermentative organism.
Answer: a [Reason:] Lactobacillus bulgaricus grows rapidly and is homofermentative and thus is capable of converting the lactose to the single end product-lactic acid.
4. What temperature is necessary for the production of vinegar?
a) 43 degree C
b) 60 degree C
c) 10-13 degree C
d) 15-34 degree C
Answer: d [Reason:] For vinegar production it is necessary to keep the temperature between 15 and 34 degree C, the optimum for growth and metabolism of the acetobacters.
5. Which of the following product is used for treatment of pernicious anemia?
Answer: c [Reason:] Cobalamin or vitamin B12 is used for treatment of pernicious anemia and also for food and feed supplements.
6. Microbial fermentation produces D optical isomers of the amino acids.
Answer: b [Reason:] Advantage of microbial fermentation processes is that the biologically active forms of the amino acids i.e. L optical isomers are produced.
7. Diaminopimelic acid (DAP) is produced by which of the following microorganism?
b) Enterobacter aerogenes
c) Bacillus subtilis
d) Streptococcus equisimilis
Answer: a [Reason:] Production of lysine involves two stages among which the first stage is the formation of diaminopimelic acid (DAP) by E.coli.
8. Which of the following raw materials are important for the production of glutamic acid?
b) corn-steep liquor
Answer: d [Reason:] For glutamic acid the medium generally consists of a carbohydrate, peptone, inorganic salts, and biotin; the concentration of biotin has a significant influence on the yield of glutamic acid.
9. Insulin was isolated from which of the following organs of animals?
a) small intestine
Answer: c [Reason:] Commercial insulin for the therapy of diabetes was isolated from animal pancreatic tissue.
10. Which of the following yeast is used for the production of riboflavin?
a) Saccharomyces cerevisiae
b) Eremothecium ashbyi
c) Saccharomyces rouxii
d) Candida utilis
Answer: b [Reason:] Eremothecium ashbyi is used for the production of riboflavin which is used as a vitamin supplement.
11. Which of the following product utilises whey as its raw material?
a) lactic acid
b) acetic acid
c) glutamic acid
Answer: a [Reason:] Whey is used for the production of lactic acid which can also be grown using other carbohydrate substances such as corn or potato starch.
Interview MCQ Set 4
1. Gluconic acid is produced by which of the following molds?
a) Aspergillus niger
b) Rhizopus nigricans
c) Aspergillus terreus
d) Rhizopus oryzae
Answer: a [Reason:] Aspergillus niger is the producer organism for gluconic acid which is used as a pharmaceutical product, textiles, leather, or in photography.
2. Fermentation of rice is carried out by which of the following microorganisms?
Answer: c [Reason:] Molds are used for the fermentation of rice to produce a variety of oriental foods and food additives.
3. Penicillium chrysogenum is a better penicillin producing species.
Answer: a [Reason:] Fleming isolated the mold Penicillium notatum which yielded only a few units of penicillin per milliliter.So isloation of a better penicillin-producing mold species, Penicillium chrysogenum helped in increasing the yield.
4. Which of the following techniques is used to improve penicillin production?
a) fed-batch fermentation
b) submerged-culture technique
c) continuous fermentation
d) batch fermentation
Answer: b [Reason:] Penicillin production can be improved by development of the submerged culture technique i.e., cultivation of the mold in large volumes of liquid medium through which sterile air is forced.
5. Which of the following product acts as a substrate for the production of citric acid?
b) corn-steep liquor
d) oyabeen meal
Answer: a [Reason:] Many sugars may serve as the substrate for the production of citric acid, however, molasses is generally used.
6. Which of the following enzymes is used to hydrolyze starch to dextrin?
Answer: c [Reason:] Amylases hydrolyze starch to dextrin and sugars and are used in preparing adhesives, clarifying fruit juices, manufacturing pharmaceuticals etc.
7. Which of the following enzyme is used in the process of bating?
Answer: d [Reason:] Proteases are used for bating i.e. treatment of hides to provide a finer texture and grain in leather processing.
8. Paper, glass beads can be used to immobilize enzymes.
Answer: a [Reason:] A variety of substances including paper, wood chips, ceramic, glass beads, and ion-exchange resins have been used to immobilize enzymes.
9. Invertase causes hydrolysis of ___________
Answer: b [Reason:] Invertase hydrolyzes sucrose to form glucose and fructose (invert sugar). It is widely used in candy making and production of noncrystallizable syrups from sucrose.
10. Rhizopus nigricans produces which of the following products?
a) Citric acid
b) Fumaric acid
c) Gibberellic acid
d) Lactic acid
Answer: b [Reason:] Rhizopus nigricans is used for the production of fumaric acid which is used in the manufacture of alkyd resins and wetting agents.
Interview MCQ Set 5
1. Which among the following are not used as raw materials for alcohol production?
Answer: c [Reason:] Corn, molasses, sugar beets, potatoes, and grapes are some of the common raw materials employed throughout the world for alcohol fermentation.
2. The organism used for alcohol fermentation should have a high tolerance for alcohol.
Answer: a [Reason:] It is imperative that the culture be one that grows vigorously and has a high tolerance for alcohol as well as a capacity for producing a large yield of alcohol.
3. What is the pH required for production of baker’s yeast?
a) 1 to 2
b) 4 to 5
c) 7 to 8
d) 10 to 12
Answer: b [Reason:] In the manufacture of baker’s yeast, the medium is adjusted to an acid pH of 4 to 5, which helps retard bacterial growth.
4. The leavening or rising of dough is due to which of the following gases?
b) carbon dioxide
d) sulphur dioxide
Answer: b [Reason:] The carbon dioxide produced during the fermentation by baker’s yeast is responsible for the leavening or rising of the dough.
5. Which of the following instrument is used for recovery of yeast cells?
c) filter press
d) mash storage
Answer: c [Reason:] The cells are finally recovered on a filter press, small amounts of vegetable oil are added as a plasticizer, and then this mass of cells is molded into blocks.
6. Which of the following product is used as a food condiment?
a) Baker’s yeast
d) Soy sauce
Answer: d [Reason:] Soy Sauce is produced by the yeast Saccharomyces rouxii and is used as a food condiment.
7. Which of the following yeast can be used to produce microbial protein?
a) Saccharomyces cerevisiae
b) Candida milleri
c) Eremothecium ashbyi
d) Candida utilis
Answer: d [Reason:] Candida utilis is yeast used for producing microbial protein which is used as an animal food supplement (single-cell protein) from paper-pulp waste.
8. The medium for production of Baker’s yeast contains only molasses and inoculum.
Answer: b [Reason:] In the manufacture of baker’s yeast the “stock” strain is inoculated into a medium which frequently contains molasses and corn-steep liquor.