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Interview MCQ Set 1

1. Which bacteria has an unusual capsule among the following?
a) Haemophilus influenzae
b) Klebsiella pneumoniae
c) Streptococcus pneumoniae
d) Bacillus anthracis

View Answer

Answer: d [Reason:] The capsule of B. anthracis is unusual in that it is composed of a polypeptide rather than a polysaccharide.

2. For Clostridium botulinum type A toxin, 1 MLD for a mouse is ____________
a) 2.5 X 10-5 µg
b) 4 X 10-5 µg
c) 6 X 10-2 µg
d) 5 µg

View Answer

Answer: a [Reason:] Clostridium botulinum type A produces the most potent toxin known: 1 MLD for a mouse is 2.5 X 10-5 µg of the purified toxin.

3. What is the chemical nature of endotoxins?
a) protein
b) polysaccharide
c) lipopolysaccharide
d) lipid

View Answer

Answer: c [Reason:] Endotoxins are lipopolysaccharide in nature and are released from cell walls of lysed Gram-negative bacteria.

4. Exotoxins are heat-labile in nature.
a) True
b) False

View Answer

Answer: a [Reason:] Exotoxins are heat-labile in nature and are inactivated easily by boiling which is not the case with endotoxins.

5. Which type of toxin is tetanus toxin?
a) enterotoxin
b) neurotoxin
c) cytotoxin
d) endotoxin

View Answer

Answer: b [Reason:] Tetanus toxins affect nerve tissues and are hence termed as neurotoxins. It comes under the broad category of exotoxins.

6. Which of the following is a plasmid-mediated toxin?
a) diphtheria toxin
b) botulism toxin
c) tetanus toxin
d) food-poisoning toxin

View Answer

Answer: d [Reason:] Plasmid-mediated toxin is the enterotoxin made by food-poisoning strains of S.aureus. Plasmid carries the gene for the toxin.

7. The B region of diphtheria toxin has the enzymatic activity.
a) True
b) False

View Answer

Answer: b [Reason:] By means of the B region the toxin binds to the membrane of a tissue cell.The A region consists of the enzymatic activity and catalyzes the reaction that inactivates elongation factor 2 (EF-2), a factor essential for elongation of polypeptide chain during protein synthesis.

8. Which amino acid is an inhibitory transmitter?
a) alanine
b) tyrosine
c) glycine
d) phenylalanine

View Answer

Answer: c [Reason:] To render neurons temporarily insensitive to stimulation, it is accomplished in the central nervous system by the action of a chemical called inhibitory transmitter, viz., the amino acid glycine.

9. Which toxin causes paralysis of muscles?
a) Diphtheria toxin
b) Botulinum toxin
c) Tetanus toxin
d) Cholera toxin

View Answer

Answer: b [Reason:] The botulinum toxin binds to the axon near the neuromuscular junction and prevents the secretion of acetylcholine; thus the muscle cannot contract and paralysis occurs.

10. How many B subunits are present in cholera toxin?
a) 1
b) 2
c) 3
d) 5

View Answer

Answer: d [Reason:] Cholera toxin consists of one A subunit and five B subunits. The B subunits are responsible for attachment of the toxin to the surface of the epithelial cells of the small intestine.

11. Which of the following statement is wrong regarding the effects of cholera toxin?
a) loss of fluid from the body
b) pH of blood remains constant
c) hemoconcentration
d) bicarbonate ions are lost from blood

View Answer

Answer: b [Reason:] Since bicarbonate ions are lost from the blood, the pH of the blood falls, which may lead to death by acidosis.

12. Which of the following toxin is a hemolysin?
a) diphtheria toxin
b) botulism toxin
c) tetanus toxin
d) streptolysin O

View Answer

Answer: d [Reason:] Streptolysin O (SLO) is a hemolysin, causing beta hemolysis around the colonies on blood-agar plates incubated anaerobically.It also acts a leukocidin.

13. Hylauronidase enzyme is is produced by which of the following organism?
a) C. perfringens
b) S. pyogenes
c) S. aureus
d) Mycoplasma

View Answer

Answer: a [Reason:] Hylauronidase enzyme is produced by the gas gangrene causing organism C. perfringens and has been thought to enhance penetration of the host tissues by hydrolyzing hyaluronic acid.

14. Which of the following has the ability to bind antibodies?
a) Coagulase
b) Streptokinase
c) Protein A
d) Hydrogen Peroxide

View Answer

Answer: c [Reason:] Protein A is located on the cell wall of S. aureus and has the ability to bind antibodies, regardless of their specificity.The antibody molecules are distorted and their binding site is exposed.

15. LT toxin is produced by _____________
a) S. aureus
b) E.coli
c) B. anthracis
d) C. perfringens

View Answer

Answer: b [Reason:] LT toxin is produced by E.coli and it is an enterotoxin, causing diarrhea. The mechanism is similar to that of cholera toxin.

Interview MCQ Set 2

1. Which of the following microbe is used in the production of blue cheese?
a) Streptococcus thermophilus
b) Lactobacillus bulgaricus
c) Penicillium roqueforti
d) Rhizopus stolonifer

View Answer

Answer: c [Reason:] For the production of blue cheese or Roquefort cheese, it is necessary to inoculate the curd with the microorganism, Penicillium roqueforti which brings about the necessary changes.

2. Pickled cucumber is made from fermented salt-stock pickles.
a) True
b) False

View Answer

Answer: b [Reason:] Most commercial sweet,sour,mixed pickles are made from fermented salt-stock pickles.The other major type of pickled cucumber is the fermented dill pickle.

3. Bacterial cell grown on hydrocarbon wastes from the petroleum industry are a source of _____________
a) carbohydrates
b) proteins
c) vitamins
d) fats

View Answer

Answer: b [Reason:] The microorganisms can be cultivated on industrial wastes or by-products as nutrients and yield a large cell crop that is rich in protein.Bacterial cell grown on hydrocarbon wastes from the petroleum industry are a source of protein in France,Japan,Taiwan, and India.

4. Yeast-cell crops harvested from the vats is used to produce which of the following compounds?
a) alcoholic beverages
b) enzymes
c) antibiotics
d) organic acids

View Answer

Answer: a [Reason:]Yeast-cell crops harvested from the vats used to produce alcoholic beverages have been used as a food supplement for generations.

5.vHow many tons of protein can be produced by algae grown in pond in a year?
a) 1000
b) 1
c) 50
d) 20

View Answer

Answer: d [Reason:] Algae grown in ponds can produce 20 tons (dry weight) of protein per acre per year.

6. What is the range of protein content in yeast cells?
a) 69%
b) 12-15%
c) 20-40%
d) 40-50%

View Answer

Answer: d [Reason:] The protein content of microbial cells is very high.Yeast cells have a protein content in a 40 to 50 percent range.

7. Which of the following microorganism have a high vitamin content?
a) bacteria
b) yeast
c) algae
d) protozoa

View Answer

Answer: b [Reason:] Some microorganisms, particularly yeasts, have a high vitamin content.The growth medium for yeast cells consists of hydrocarbons supplemented with mineral salts.

8. The principal microorganism for yogurt is ______________________
a) Streptococcus thermophilus
b) Leuconostoc citrovorum
c) Lactobacillus acidophilus
d) Streptococcus lactis

View Answer

Answer: a [Reason:] Streptococcus thermophilus and Lactobacillus bulgaricus are among the principal microorganisms responsible for producing yogurt by fermentation.

9. Which of the following products have higher acidity and lacks aroma?
a) Cultured buttermilk
b) Cultured sour cream
c) Bulgarian milk
d) Acidophilus milk

View Answer

Answer: c [Reason:] For production of Bulgarian milk by Lactobacillus bulgaricus, incubation of inoculated milk at 37 degree C is carried out and product differs from commercial buttermilk in having higher acidity and lacking aroma.

10. Shredded cabbage is the starting product for which of the following fermented food?
a) Sauerkraut
b) Pickles
c) Green olives
d) Sausage

View Answer

Answer: a [Reason:] Shredded cabbage acts as a starting product for producing fermented product sauerkraut.Enterobacter cloacae is used in the early stage of fermentation.

Interview MCQ Set 3

1. Which of the following is not a desired characteristic of the organism to be used for industrial application?
a) should produce less amount of product
b) should be readily available
c) should grow rapidly
d) should be nonpathogenic

View Answer

Answer: a [Reason:] The organism to be used must be able to produce appreciable amount of the product.It should be readily available and should grow rapidly and vigorously.It should be nonpathogenic.

2. Industrial fermentation are performed in large tanks of capacity ______________
a) 100 gal
b) 1000 gal
c) 50,000 gal
d) 10,000 gal

View Answer

Answer: c [Reason:] Industrial fermentation are performed in large tanks; capacities of 50,000 gal are not unusual.

3. Solvents and enzymes are found in which of the following categories of microbial products?
a) Pharmaceutical chemicals
b) Commercially valuable chemicals
c) Food supplements
d) Alcoholic beverages

View Answer

Answer: b [Reason:] Solvents,enzymes, and intermediate compounds for the synthesis of other substances are representative of the kinds of substances produced commercially by microorganisms.

4. Which of the following enzymes cut the DNA molecule at particular nucleotide sequence?
a) restriction endonuclease
b) exonuclease
c) ligase
d) polymerase

View Answer

Answer: a [Reason:] Restriction endonuclease cut double-stranded DNA molecules at particular nucleotide sequences and thus produce a well-defined DNA fragment for a given enzyme and a given DNA.

5. Eco R1 cuts the plasmid DNA and the donor DNA such that both the ends are same.
a) True
b) False

View Answer

Answer: b [Reason:] The endonuclease Eco R1 cuts the plasmid DNA and the donor DNA in a manner such that the ends of each are identical and self-complementary.

6. Which of the following product is used for the treatment of blood clots?
a) insulin
b) interferon
c) urokinase
d) somatostatin

View Answer

Answer: c [Reason:] The pharmaceutical industry has already produced several products for human therapy by the help of genetic engineering such as urokinase that is used for treatment of blood clots; human insulin and interferons.

7. VP3 protein is isolated from which of the following viruses?
a) TMV
b) HIV
c) HRV
d) FMDV

View Answer

Answer: d [Reason:] VP3 is the protein from the shell of the foot-and-mouth disease virus (FMDV), which can act as a vaccine for immunizing livestock against foot-and-mouth disease.

8. Transfection involves the introduction of plasmid hybrid DNA into the host cell.
a) True
b) False

View Answer

Answer: b [Reason:] Transfection involves the introduction of phage hybrid DNA into the host cell whereas transformation involves introduction of plasmid hybrid DNA into a competent host bacterial cell.

Interview MCQ Set 4

1. Fungi are ______________
a) prokaryotic
b) eukaryotic
c) prokaryotic and lack chlorophyll
d) eukaryotic and lack chlorophyll

View Answer

Answer: d [Reason:]Fungi are eucaryotic spore-bearing protists that lack chlorophyll.They are of great practical and scientific interest to microbiologists.

2. Hyphal wall consists of microfibrils composed of ___________________
a) hemicellulose or chitin
b) cellulose
c) lipids
d) proteins

View Answer

Answer:a [Reason:] The hyphal walls of fungi consists of microfibrils composed for the most part of hemicellulose or chitin; true cellulose occurs only in the walls of lower fungi.

3. Coenocytic hyphae have ________________
a) septate with uninucleate cells
b) septate with multinucleate cells
c) no septate
d) no septate with uninucleate cells

View Answer

Answer: c [Reason:] Coenocytic hyphae are also known as nonseptate hyphae and hence have no sep-ta.

4. What are the dimensions of the filaments that the thallus of a fungus consists of?
a) 1 micrometre
b) 5 to 10 micrometre
c) 1 metre
d) 1 centimetre

View Answer

Answer: b [Reason:] The thallus or body of a fungus consists of filaments, 5 to 10 micrometre across, which are commonly branched.

5. The yeast cell or mould filament is surrounded by a true cell wall.
a) True
b) False

View Answer

Answer: a [Reason:] The yeast cell or mould filament is surrounded by a true cell wall.The exception being the slime moulds, which have a thallus consisting of a naked amoeboid mass of proto-plasm.

6. What do the term dimorphic mean?
a) Bisexual
b) Unisexual
c) Exists in two forms
d) Exists in single form

View Answer

Answer: c [Reason:] Some fungi are dimorphic, that is, they exist in two forms.Some pathogenic fungi have a unicellular and yeastlike form in their host, but when growing saprophytically in soil or in laboratory medium they have a filamentous mold form.

7.Yeasts have flagella for the purpose of locomotion.
a) True
b) False

View Answer

Answer: b [Reason:] Yeasts have no flagella or other organelles of locomotion.

8. The crosswalls constrict which of the following parts and then grow inwards to form septum?
a) hyphae
b) lumen
c) protoplasm
d) plasmalemma

View Answer

Answer: d [Reason:] The crosswalls constrict the plasmalemma and grow inward to form generally an incomplete septum that has a central pore which allows for protoplasmic streaming.

9. The plasmalemma surrounds which of the following?
a) lumen
b) wall
c) protoplasm
d) hyphae

View Answer

Answer: c [Reason:] Between the protoplasm and the wall is the plasmalemma, a double-layered mem-brane which surrounds the protoplasm.

Interview MCQ Set 5

1. Leishmania donovani measures _____________ in length.
a) 600 micrometre
b) 1 to 4 micrometre
c) 2 mm
d) 2000 micrometre

View Answer

Answer: b [Reason:] Leishmania donovani, the cause of human disease kala azar, measures 1 to 4 micrometre in length.

2. Protozoan mobility is due to the fibrils present.
a) True
b) False

View Answer

Answer: b [Reason:] Protozoan contractility is probably due to the fibrils.Submicroscopic protein fibrils are groups of parallel fibrils in the cytoplasm.

3. Plasmagel is known as __________________
a) cytoplasm
b) endoplasm
c) ectoplasm
d) myonemes

View Answer

Answer: c [Reason:] Plasmagel is known as the ectoplasm.The cytoplasm is differentiated into endoplasm and ectoplasm.The ectoplasm is more gel-like and the endoplasm is more voluminous and fluid.

4. Golgi bodies are also known as __________________
a) dictyosomes
b) kinetosomes
c) blepharoplasts
d) myonemes

View Answer

Answer: a [Reason:] Golgi complexes are also known as dictyosomes which means piles of membranous sacs.

5. The micronucleus in protozoa is concerned with reproductive activity.
a) True
b) False

View Answer

Answer: a [Reason:] The micronucleus is concerned with reproductive ability whereas the macronucleus controls the metabolic activities and regeneration processes.

6. How many haploid chromosomes are present in Spirotrichonympha polygyra?
a) 60
b) 7
c) 2
d) 40

View Answer

Answer: c [Reason:] It has been shown that number of chromosomes is constant for a particular species of protozoan.Spirotrichonympha polygyra has 2 haploid chromosomes.

7. Amoeba proteus have a diffuse layer of which of the following over the plasmalemma?
a) glucose
b) chitin
c) cellulose
d) mucopolysaccharides

View Answer

Answer: d [Reason:] Amoeba proteus have a diffuse layer of mucopolysaccharides over the plasmalemma.This layer is thought to play an important role in pinocytosis or in adhesion of the cell to the substratum.

8. Among the following which layer is directly apposed to the cell surface?
a) tests
b) theca
c) shells
d) loricae

View Answer

Answer: b [Reason:] The theca is a secreted layer directly apposed to the cell surface.Tests,shells,and lorica are coverings that are loosely apposed to the cell surface.Tests,shells,and lorica are coverings that are loose-fitting.

9. Which of the following is the actual opening in ciliates through which food is ingested?
a) cytosome
b) oral groove
c) peristome
d) cytopharynx

View Answer

Answer: a [Reason:] In ciliates the cytosome is the actual opening through which food is ingested.It ranges from a simple round opening to a slitlike structure surrounded by feeding membranelles.

10. Which of the following protective structures occur in the tentacles of suctorian protozoa?
a) mucocysts
b) trichocysts
c) toxicysts
d) haptocysts

View Answer

Answer: d [Reason:] Haptocysts occur in the tentacles of suctorian protozoa and are used to contact and immobilize prey.