Interview MCQ Set 1
1. Which of the following inclusion bodies are present in the cytoplasm of the Purkinje cells of the cerebellum in case of rabies infection?
a) Paschen bodies
b) Guarnieri bodies
c) Negri bodies
d) Elementary bodies
Answer: c [Reason:] Characteristic inclusion bodies are found in the cytoplasm of the Purkinje cells of the cerebellum and in certain other nerve cells in cases of rabies infection.These typical inclusion bodies are Negri bodies and is diagnostic of the disease.
2. Bollinger bodies are found in the cytoplasm of cells infected by which of the following viruses?
a) variola virus
b) fowl pox virus
c) rabies virus
d) herpes virus
Answer: b [Reason:] Bollinger bodies are found in the cytoplasm of cells infected with fowl pox virus.It is a type of inclusion body produced by viruses in certain host tissues.
3. Intracytoplasmic inclusions are found in chicken pox, herpes, and the polyhedra diseases of insects.
Answer: b [Reason:] Intranuclear inclusions are found in chicken pox, herpes, and the polyhedra diseases of insects.Intranuclear and intracytoplasmic inclusions may be found in the same cell in instances of multiple infection.
4. Scrapie is a chronic disease of which of the following animals?
Answer: a [Reason:] Scrapie is so named because the diseased animal tends to scrape against fixed objects.It is a chronic infection of the central nervous system of sheep.
5. In which of the following categories of cancer solid tumors grow from derivatives of embryonal mesoderm?
Answer: c [Reason:] In Sarcoma solid tumors grow from derivatives of embryonal mesoderm, such as connective tissues, cartilage, bone, muscle and fat.
6. Anaplasia is structural abnormality of cells.
Answer: a [Reason:] Cancer has three major characteristics: hyperplasia, anaplasia, and metastasis. Anaplasia is structural abnormality of cells (these cells also have a loss of or reduction in their functions).
7. Which among the following is the family of RNA containing viruses that can cause cancer in animals?
Answer: d [Reason:] Among the viruses whose virions contain RNA, only some members of the family Retroviridae cause cancer in animals.These members replicate through a DNA intermediate.
8. Cancer of the lip of mouth have been associated with ___________
d) SV 40
Answer: a [Reason:] HSV1 is a herpes virus type 1 which is associated with the cancer of the lip of the mouth in humans wheras HSV2 causes cervical cancer.
9. The Epstein-Barr virus (EBV) can induce tumors in _____________
Answer: c [Reason:] The Epstein-Barr virus (EBV), a herpesvirus, has been consistently associated with certain human neoplasias, or tumors.
Interview MCQ Set 2
1. Degree of pathogenicity is referred to as _________________
Answer: b [Reason:] Various strains of pathogenic species differ with regard to their degree of pathogenicity, i.e., with regard to their virulence.
2. Which type of strains are used in vaccines?
Answer: c [Reason:] Attenuated strains are widely used as vaccines to elicit immunity to various diseases.
3. The LD50 dose can be determined more precisely than LD100 dose.
Answer: a [Reason:] The LD50 dose can be determined more precisely than LD100 dose because the rate of change in mortality versus change in dose is greatest around the point of 50 percent mortality.
4. Which of the following characteristics of the microorganism does not help in causing the infectious disease?
a) must enter the host
b) must metabolize in the host tissue
c) must resist host defenses
d) must not damage the host
Answer: d [Reason:] The pathogenic microorganism after entering the host must also damage the host to cause any infectious disease.
5. Microbial adherence is selective in nature.
Answer: a [Reason:] Microbial adherence or attachment of the pathogen to some surface of the host is selective: various pathogens attach only to certain tissues.
6. When the infection occurs suddenly and with severe intensity it is known as ______________
Answer: b [Reason:] Fulminating type of infection occurs suddenly and with severe intensity. Example is cerebrospinal meningitis caused by Neisseria meningitidis.
7. Tuberculosis is which type of infection?
Answer: b [Reason:] Chronic infections are those diseases which has a long duration like tuberculosis disease.
8. Where does Streptococcus pyogenes infects in the body to cause infection?
b) small intestine
Answer: d [Reason:] Streptococcus pyogenes, the causative agent of streptococcal sore throat, attaches specifically to the epithelial cells of the throat by means of cell wall proteins.
9. Vibrio cholerae adheres to the epithelial cells of the small intestine by means of ______________
d) hydrogen bonds
Answer: c [Reason:] Vibrio cholerae adheres to the epithelial cells of the small intestine of humans by means of hemogglutinin.
10. Poliovirus attaches to central nervous system by means of ______________
d) hydrogen bonds
Answer: b [Reason:] There is a protein on the surface of poliovirus which seems to be critical for attachment of the virus to lipid- and glycoprotein- containing receptors on the host cells; the attachment is specific for cells of the intestinal tract and central nervous system.
Interview MCQ Set 3
1. Type strain is used for referring to?
Answer: a [Reason:] Bacterial species consists of a special strain called type strain which have similar characteristics. Bacterial genus is composed of a collection of similar species and is referred to as type species.
2. The correct order of taxonomic groups from higher to lower rank is?
Answer: d [Reason:] Taxonomists have made the classification based on two qualities—stability and predictability. The order of taxonomic groups from higher rank to lower rank is:Kingdom—Division—Class—Order—Family—Genus—Species.
3. % Similarity (%S) of each strain to every other strain is calculated by which method?
a) Intuitive Method
b) Numerical Taxonomy
c) Genetic Relatedness
d) DNA homology experiments
Answer: b [Reason:] %S = NS
where, %S is % similarity of each strain to every other strain,NS is the number of characteristics that are the same for the two strains, and ND is the number of characteristics that are different. Thus this is determined by numerical taxonomy.
4. Two organisms which are very closely related to each other have which of the following property?
a) similar mol% G+C values
b) different mol% G+C values
c) similar mol% G+C values and heteroduplexes are formed.
d) different mol% G+C values and heteroduplexes are not formed.
Answer: c [Reason:] Two organisms of the same species that are very closely related to each other will have very similar mol% G+C values and their single strands of DNA molecules combine to form heteroduplexes. Organisms which are not closely related have different mol% G+C values and hence do not form heteroduplexes.
5. What are ribosomes composed of?
d) Proteins and RNA
Answer: d [Reason:] Ribosomes, the small granular-appearing structures within the cell which manufacture proteins, are composed of proteins and RNA.The ribosomal RNA (rRNA) is coded for by only a small fraction of the DNA molecule, the rRNA cistrons.
6. If two organisms are distantly related and show no DNA homology there still may be similarity in their rRNA cistrons.
Answer: a [Reason:] The nucleotide sequence of rRNA genes has been found to be highly conserved. So even if two organisms are only distantly related and show no significant DNA homology, there still maybe similarity in the nucleotide sequences of their rRNA cistrons. The degree of similarity that exists can then be used as a measure of relatedness between organisms.
7. Which of the following are characteristics of archaebacterial different from eubacteria?
b) extreme halophiles
d) methane-producers,extreme halophiles,and thermoacidophiles
Answer: d [Reason:] Eubacteria are the traditional, familiar ones that have received the most study.Archaebacteria the other group consists of methane producers, extreme halophiles and thermoacidophiles.
8. Which among the following come under Gram-positive eubacteria?
Answer: d [Reason:] Based on rRNA oligonucleotiding, Clostridium and Actinomyces come under Gram-positive eubacteria. Rhizobium belongs to Purple eubacteria.
9. Which among the following kingdoms were proposed by Whittaker?
Answer: d [Reason:] R.H.Whittaker classified microorganisms on the basis of nutritional requirements and formed Whittaker’s Five Kingdom and they are Monera (bacteria and cyanobacteria),Protista (microalgae and protozoa),Fungi (yeasts and molds),Plantae (multicellular green plants and higher algae) and Animalia (multicellular animals).
10. According to Bergey’s Manual of Systematic Bacteriology, prokaryotes that lack a cell wall belong to the group?
Answer: c [Reason:] Tenericutes are prokaryotes that lack a cell wall. Gracilicutes are prokaryotes with a complex cell-wall structure characteristic of Gram-negative bacteria.Firmicutes are prokaryotes with a cell wall structure characteristic of Gram-positive bacteria and Mendosicutes are prokaryotes that show evidence of an earlier phylogenetic origin.
Interview MCQ Set 4
1. Which of the following organism occurs on the skin of fresh poultry?
Answer: a [Reason:] Pseudomonads constitute the major contaminantson the skin of freshly dressed poultry.
2. What is the pH of bananas?
Answer: b [Reason:] The pH of fruits is relatively acid ranging from 2.3 for lemons to 5.0 for bananas.
This restricts bacterial growth but does not retard fungal growth.
3. Raw milk of good sanitary quality will develop sweet flavour.
Answer: b [Reason:] Raw milk of good sanitary quality will develop a clean,sour flavour.This change is brought about mainly by Streptococcus lactis and S.cremoris.
4. At what temperature pasteurization of milk takes place?
a) 650 C
b) 370 C
c) 62.80 C
d) 450 C
Answer: c [Reason:] The holding method of pasteurization exposes milk to a temperature of 62.80 C for 30 mins.
5. Which among the following is a gas producer organism?
a) Streptococcus lactis
b) Lactobacillus fermentum
c) Micrococcus luteus
d) Clostridium butyricum
Answer: d [Reason:] Clostridium butyricum causes fermentation of lactose with accumulation of gas.The gas may be a mixture of carbon dioxide and hydrogen or only carbon dioxide in case of yeast fermentation.
6. Which among the following group of microorganisms are found in the ducts of cow’s mammary glands?
Answer: c [Reason:] Micrococci such as Micrococcus luteus, Micrococcus varians are found in the ducts of cow’s mammary glands and dairy utensils.They are acid producers and are weakly proteolytic.
7. The coloration of the milk is caused by which of the following organism?
a) Pseudomonas sp.
b) Bacillus sp.
c) Penicillium sp.
d) Streptococcus sp.
Answer: a [Reason:] Pseudomonas sp. may produce coloration of milk.End products of proteolysis may impart abnormal flavor or odor to the milk.
8. In which of the following biochemical types of microorganisms a slime layer or capsule is formed on the cells?
a) Acid producers
b) Gas producers
c) Ropy or stringy fermentation
Answer: c [Reason:] In Ropy or stringy fermentation, organisms synthesize a viscous polysaccharide material that forms a slime layer or capsule on the cells. They include Alcaligenes viscolactis, Enterobacter aerogenes, etc.
9. Tuberculosis brucellosis is caused by the pathogen from an infected cow.
Answer: a [Reason:] Pathogen from infected cow are transmitted through milk to humans or cow and causes tuberculosis brucellosis, mastitis.
10. Which of the following type of spoilage occurs in fresh meat?
Answer: c [Reason:] Fresh meat is spoiled by putrefaction and is caused by Alcaligenes, Clostridium, Proteus vulgaris etc. In putrefaction, the protein foods are degraded by proteolytic microorganisms to give amino acids, amines, ammonia and hydrogen sulphide.
11. Spoilage of bread is caused by which of the following microorganism(s)?
Answer: b [Reason:] Moldy and ropy type of spoilage occurs in bread which are caused by Rhizopus nigricans, Penicillium, Aspergillus niger and Bacillus subtilis.
12. The thermophilic anaerobe spoilage of low and medium acid canned products are caused by _____________
a) Bacilllus stearothemophilus
b) Clostridium thermosaccharolyticum
c) Bacillus thermoacidurans
d) Clostridium sporogenes
Answer: b [Reason:] Thermophilic anaerobe spoilage of low and medium acid canned products such as corn,peas,spinach are caused by Clostridium thermosaccharolyticum.Can swells and may burst.
Interview MCQ Set 5
1. The dye eosinate of methylene blue belongs to which group?
a) Acidic dye
b) Basic dye
c) Neutral dye
d) Oxazine dye
Answer: c [Reason:] A neutral dye is a complex salt of a dye acid with a dye base so eosinate of methylene blue is an example of a neutral dye. An acidic dye is one in which the charge on the dye ion is negative and a basic dye is one in which the charge carried by the dye ion is positive.
2. What is the correct order of staining reagents in Gram-Staining?
a) Crystal violet, alcohol, iodine solution, safranin
b) Crystal violet, iodine solution, alcohol, safranin
c) Crystal violet, safranin, alcohol, iodine solution
d) Iodine solution, crystal violet, alcohol, safranin
Answer: b [Reason:] Gram staining is a type of differential staining. In this process the fixed bacterial smear is subjected to the following staining reagents in the order listed: crystal violet, iodine solution, alcohol (decolorizing agent), and safranin.
3. Which bacteria appears purple-violet colour after staining?
c) Both Gram-positive and Gram-negative
d) Neither Gram-positive nor Gram-negative
Answer: a [Reason:] Gram-positive bacteria retain the crystal violet and hence appear deep purple-violet colour as it has a higher content of peptidoglycan layer. Gram-negative bacteria have lesser amount of peptidoglycan layer and on treatment with alcohol it loses the purple-violet colour, are counterstained by safranin and hence appears red.
4. Which of the following are true for Gram-negative bacteria?
a) upon alcohol treatment, the permeability of the cell wall increases
b) crystal violet-iodine (CV-I) complex is extracted
c) pore size decreases and the CV-I complex cannot be extracted
d) alcohol treatment increases the permeability of the cell wall and the CV-I complex can be extracted
Answer: d [Reason:] Experimental evidence suggests that during staining of Gram-negative bacteria the alcohol treatment extracts the lipid, which results in increased permeability of the cell wall. Thus the crystal violet-iodine (CV-I) complex can be extracted and the Gram-negative organism is decolorized. These cells subsequently take on the color of the safranin counterstain.
5. Gram-positive bacteria are usually more susceptible to?
Answer: c [Reason:] Gram-positive bacteria are usually more susceptible to penicillin and less susceptible to disintegration by mechanical treatment or exposure to some enzymes than Gram-negative bacteria. Gram-negative bacteria are more susceptible to other antibiotics like streptomycin.
6. Which of the staining technique helps in demonstrating spore structure in bacteria as well as free spores?
a) Acid-fast stain
b) Endospore stain
c) Capsule stain
d) Flagella stain
Answer: b [Reason:] There are numerous other staining techniques designed to identify some particular feature of cell structure or composition. Endospore staining demonstrates spore structure in bacteria as well as free spores.
7. In Gram-staining, iodine is used as a______________
Answer: b [Reason:] In Gram-staining, iodine acts as a mordant i.e. it combines with the dye or stain and thereby fixes it on the material. It increases the interaction between stain solution and the bacterial cell.
8. Which of the following is the example of Gram-negative bacteria?
b) Eschericia coli
c) Staphylococcus aureus
d) Bacillus subtilis
Answer: b [Reason:] Eschericia coli is an example of Gram-negative bacteria. Others are all examples of Gram-positive bacteria.