Interview MCQ Set 1
1. Growth of bacteria or microorganisms refer to __________________
a) an increase in the size of an individual organism
b) an increase in the mass of an individual organism
c) changes in the total population
d) an increase in number of cells
Answer: d [Reason:] Growth denotes the increase in number of cells beyond that present in the original inoculum. It does not refer to an increase in size or mass of an individual organism.
2. Transverse binary fission requires the formation of a crosswall.
Answer: a [Reason:] The most important mode of cell division in the usual growth of bacterial population is transverse binary fission, in which a single cell divides after developing a transverse septum(crosswall).
3. Which of the following bacterial species divides by fragmentation?
a) Bacillus subtilis
b) Streptococcus faecalis
c) Rhodopseudomonas acidophila
d) Nocardia sp.
Answer: d [Reason:] Bacteria that produce extensive filamentous growth, such as Nocardia sp. reproduce by fragmentation of the filaments into small bacillary or coccoid cells, each of which gives rise to new growth.
4. Rhodopseudomonas acidophila reproduces by which of the following methods?
a) Binary fission
Answer: b [Reason:] Rhodopseudomonas acidophila reproduce by budding, a process in which a small protuberance(bud) develops at one end of the cell;this enlarges and eventually develops into a new cell which separates from the parent.
5. Streptomyces sp. show the budding mode of reproduction.
Answer: b [Reason:] Streptomyces sp. produce many spores per organism by developing crosswalls(septation) at the hyphen tips and then each spore gives rise to a new organism.
6.The synthesis of new membrane material during reproduction in Gram-positive cells is performed by which of the following organelles?
c) Endoplasmic Reticulum
d) Cytoplasmic membrane
Answer: b [Reason:] The first step in reproduction is an inward growth of the cytoplasmic membrane at the middle of the cell.A mesosome which is usually attached to the cytoplasmic membrane in Gram-positive cells, have a role in the synthesis of new membrane material.
7. Equatorial ridge formation in the cell wall takes place in which of the following bacteria?
a) Streptomyces sp.
b) Bacillus subtilis
c) Streptococcus faecalis
d) Escherichia coli
Answer: c [Reason:] In Streptococcus faecalis, all of the new wall material formed by the dividing cell is made during synthesis of the septum which begins beneath an equatorial ridge in the cell wall.
8. When septum formation occurs near the pole of cell then it results in the formation of daughter cell known as _________
d) daughter cell
Answer: c [Reason:] In some mutants of E.coli and B.subtilis, septum forms near the pole resulting in a very small daughter cell termed as minicell which lacks DNA and therefore cannot multiply.
9. A bleb or fold like formation occurs in which of the following bacteria?
a) Rhodopseudomonas acidophila
b) Bacillus subtilis
d) Streptococcus faecalis
Answer: c [Reason:] In E.coli a bleb or fold of the outer membrane occurs at the site where the septum will be formed; it is not evident in the final stages of septum formation.The cytoplasmic membrane and the peptidoglycan layer grow inward in the early stages but the cytoplasmic membrane does not invaginate until the final stages of septum formation.
10. Which of the following does not occur during binary fission in bacteria?
a) Cell elongation
c) DNA duplication
d) Spindle formation
Answer:d [Reason:] Binary fission is a form of asexual reproduction which starts with cell elongation followed by division of cytoplasm(cytokinesis) and nucleus and finally DNA duplication occurs resulting in the formation of two daughter cells.
Interview MCQ Set 2
1. Which of the following type of fission takes place in flagellates?
b) right angle to the cell axis
d) cytoplasm protrudes from the aperture
Answer: a [Reason:] In flagellates, with the exception of the dinoflagellates,fission is longitudinal along the major body axis.Since the flagella themselves are incapable of division, they must be regenerated from the basal bodies.
2. Which of the following does not take place in transverse fission?
a) fission occurs at right angle to the long cell axis
b) equatorial furrow appears
c) cytoplasm protudes from the aperture
d) constriction occurs forming two daughter cells
Answer: c [Reason:] In transverse fission which is characteristic for ciliates, fission occurs at a right angle to the long axis of the cell.An equatorial furrow appears first which separates the surafce cell layer into an anterior and a posterior half.A constriction follows,leading to the separation of two daughter cells.
3. During asexual binary fission the macronucleus divides by mitotic division.
Answer: b [Reason:] In ciliates,during asexual binary fission the diploid micronucleus divides normally by mitotic division.The macronucleus undergoes DNA synthesis and divides into two portions without the regular reduplication of the chromosomes(amitosis).
4. Plasmodium divides by which of the following method most commonly?
a) Binary fission
b) Multiple fission
Answer: b [Reason:] The malarial parasite,Plasmodium divides by the process of multiple fission where it is known as schizogony and serves to spread the parasite quickly in the host.
5. The swarming daughter cells possess special locomoter organelles like the parent cell.
Answer: b [Reason:] The swarming daughter cells differs from the parent cell not only in a lower degree of differentiation but also in the possession of special locomotor organelles.
6. Definite exogenous budding occurs in which of the following species of protozoa?
Answer: c [Reason:] Definite exogenous budding is seen in suctorians when a portion or portions of an adult sessile suctorian bud from the parent,develop cilia, and swim away.
7. When the gametes are morphologically alike, they are called ______________
Answer: a [Reason:] When the gametes (which develop from trophozoites) are morphologically alike,they are called isogametes.When they are unlike they are known as anisogametes.
8. Long,slender bodies with an oval nucleus and capable of producing new infection are known as _________________
Answer: b [Reason:] Anisogamy in Plasmodium vivax results in the formation of ookinetes or motile zygotes which give rise to a large number of sporozoites which are long,slender bodies with an oval nucleus and firm cuticle, capable of producing new infection.
Interview MCQ Set 3
1. Which of the following infect arthropods only?
Answer: c [Reason:] The Wolbachieae are not pathogenic for vertebrates,they infect arthropods only.
2. The Rickettsias and Chlamydias are similar in all respects.
Answer: b [Reason:] The Rickettsias synthesize ATP as a source of energy whereas Chlamydias cannot synthesize ATP.
3. Classical typhus fever is transmitted by which of the following arthropod?
Answer: d [Reason:] Classical typhus fever is caused by Rickettsia species and the arthropod vector which transmits the disease is lice.
4.”Growing epicellularly” means _______________________
a) on the surface of host cells
b) within the host cell
c) engulfing the host cell
d) damaging the cell membrane of host cell
Answer: a [Reason:] Growing epicellularly means growing on the surface of host cells.Rochalimaea grow epicellularly rather than in the cytoplasm or nucleus.
5. Which of the following genus of Rickettsiaceae have a high resistance to heat?
Answer: c [Reason:] The organisms belonging to Coxiella have an unusually high resistance to heat [may survive a temperature of 62 degree C for 30 mins], probably due to occurrence of endospore-like structures in the cells.
6. C.burnetti causes which of the following diseases?
a) Q fever
b) Trench fever
c) Rocky Mountain spotted fever
Answer: a [Reason:] C.burnetti is the causative agent of the Q fever, a type of pneumonia.It belongs to the family Rickettsiaceae.
7. Biting flies occur in which of the following place?
b) North America
c) South America
Answer: c [Reason:] Biting flies occur along the western slopes of the Andes mountains in South America. They transmit Oroya fever in humans.
8. Initial body in reproduction of Chlamydias is larger than the elementary body.
Answer: a [Reason:] Within the vacuole the elementary body is reorganized into a reticulate body known as initial body, which is two or three times the size of the elementary body and contains a less dense arrangement of nucleoid material.
9. Which is the most prevalent sexually transmitted disease in US?
c) lymphogranuloma venerum
d) nongonococcal urethritis
Answer: d [Reason:] Nongonococcal urethritis is the most prevalent sexually transmitted disease in the United States and is caused by the organisms belonging to the genus Chlamydia.
Interview MCQ Set 4
1. Isolation of pure culture refers to ___________
a) purification of culture
b) introduction of inoculum
c) separation of a single colony
d) to grow microorganisms on a surface
Answer: c [Reason:] To study the characteristics of one species, that species must be separated from all the other colonies of species, i.e., it must be isolated in pure culture.
2. Enrichment media allows the growth of a large number of varied bacterial species.
Answer: b [Reason:] Enrichment media is a selective method used for the enhancement of growth of a particular bacterial species.
3. Which of the following is not a physical method for selection of pure culture?
a) Heat treatment
b) pH of the media
c) Cell size and motility
d) Use of dilute media
Answer: d [Reason:] Use of dilute media is a chemical method of selection in which a mixed culture was inoculated into a very dilute medium to isolate a particular bacterial colony.
4. In physical method of selection, endospore-forming bacteria can be obtained by heating the mixed culture to _____________
a) 70 degree C for 10 minutes
b) 80 degree C for 10 minutes
c) 60 degree C for 10 minutes
d) 90 degree C for 10 minutes
Answer: b [Reason:] To select for endospore-forming bacteria,a mixed culture can be heated to 80 degree C for 10 minutes before being used to inoculate culture media.Vegetative cells will be killed by this treatment but endospores will survive and subsequently germinate and grow.
5. Vibrio cholerae can grow in a medium with a pH of _______
Answer: c [Reason:] Vibrio cholerae, cholera causing bacterium can be selected from a medium with a ph of 8.5; most intestinal bacteria are unable to grow at this pH.
6. Disease-producing species occurring in a mixed culture can be selected by taking advantage of _________
a) its pathogenic properties
b) special carbon source
c) special nitrogen source
d) toxic chemicals
Answer: a [Reason:] In the biological method of selection, a disease producing species occurring in a mixed culture can often be selected by taking advantage of its pathogenic properties. Others are chemical methods of selection.
7. Treponema sp. can be selected by taking advantage of ____________
a) small cell size
c) dilute media
d) small cell diameter and bacterial motility
Answer: d [Reason:] Treponema sp. from human oral cavity can be selected by taking advantage of its small diameter and bacterial motility. They have the ability to swim through solid agar media.
8. A large cluster of colonies are obtained in streak plate method.
Answer: b [Reason:] In streak plate method, the bacterial cells are thinned out so that the bacterial cells are far apart in the medium to ensure that colony developing from one cell does not merge with that growing from another.
Interview MCQ Set 5
1. The endoflagella is present in which class of bacteria?
Answer: b [Reason:] Spirochetes have an ability to twist or contort their shape due to the occurrence of a special kind of flagella termed periplasmic flagella or endoflagella.
2. Where is the endoflagella located in Spirochetes?
a) In the cell membrane
b) In the cytoplasm
c) In the peptidoglycan layer
d) In the periplasmic space
Answer: d [Reason:] In spirochetes, the endoflagella or as it is called periplasmic flagella is located between the outer membrane and the protoplasmic cylinder; thus they are located in the periplasmic space of the cell.
3. Spirochetes like other bacteria swim best in media of low viscosity.
Answer: b [Reason:] Spirochetes because of the added advantage of having an endoflagella swims best in media of high viscosity, whereas bacteria with ordinary flagella swim best in media of low viscosity.
4. Which of the following methods is used for viewing spirochetes?
a) Bright-field microscopy
b) Phase-contrast microscopy
c) Dark-field microscopy
d) Electron microscopy
Answer: c [Reason:] Most spirochetes are so thin that they cannot be easily seen by light microscopy, even when Gram-stained; however, dark-field microscopy does provide sufficient contrast and is the method of choice for visualizing these organisms.
5. The family Leptospiraceae are aerobes.
Answer: a [Reason:] The family Leptospiraceae of spirochetes are aerobes who use long-chain fatty acids as the carbon and energy source.
6. Which among the following are microaerophilic bacteria?
Answer: d [Reason:] Borrelia is the genus of bacteria belonging to the class Spirochaetaceae and are microaerophilic.
7. Which of the following bacteria causes syphilis in humans?
a) Treponema dysenteriae
b) Treponema pallidum
c) Leptospira biflexa
d) Leptospira interrogans
Answer: b [Reason:] Treponema pallidum causes syphilis in humans and is microaerophilic. They belong to the family Spirochaetaceae and are found in the mouth,intestinal tract, and genital areas of humans and animals.
8. Which of the following have bipolar tufts of flagella?
Answer: a [Reason:] Aquaspirilla are helical or vibroid organisms that typically possess bipolar tufts of flagella. They may be aerobic or microaerophilic and occur in stagnant stream or pond water.
9. Which of the following causes diarrhea in humans?
Answer: c [Reason:] C.jejuni causes diarrhea in humans and belong to the genus Campylobacters.They are microaerophilic parasites and occur in the reproductive organs, intestinal tract, and oral cavity of humans and other mammals.
10. Which genus among the following has certain similarities to the genus Bdellovibrio?
Answer: d [Reason:] The genus Vampirovibrio has certain similarities to the genus Bdellovibrio, but the organisms attack eukaryotic algae, not bacteria.
11. Which group of bacteria among the following give a positive reaction by the oxidase test?
b) Aerobic/Microaerophilic, Motile,Helical/Vibroid,Gram-negative bacteria
c) Non-motile,Gram-negative, Curved bacteria
d) Aerobic,Gram-negative rods and cocci
Answer: b [Reason:] Aerobic/Microaerophilic,motile,Helical/Vibroid,Gram-negative bacteria are organisms which usually give a positive reaction by the oxidase test.It is a laboratory test based on the presence of cytochrome c.