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Microbiology

Description: GATE
Number of Questions: 15
Created by:
Tags: GATE Role of Microorganisms in Transformation of Organic Matter and in the Causation of Diseases.
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Which of the following are not features of prokaryotes?

  1. Cell membrane
  2. Mitochondria
  3. Golgi complex
  4. Ribosome
  5. Cytoplasm
  6. Lysosomes
  1. Only 1, 2 and 4

  2. Only 2, 3 and 4

  3. Only 2, 3 and 6

  4. Only 3, 4, and 5

  5. Only 4, 5 and 6


Correct Option: C
Explanation:

Mitochondria, Golgi complex, Lysosomes: All the three are not found in prokaryotes

Which of the following statements are true about bacterial cell?

  1. The bacterial cell wall is composed of chitin.
  2. The cytoplasm of a bacterium is supported by microtubules.
  3. A gram-positive bacterium is stained purple by the gram stain.
  4. Bacterial flagella propel the cell by using a rotating motion.
  1. Only 1 and 2

  2. Only 1 and 3

  3. Only 2 and 3

  4. Only 2 and 4

  5. Only 3 and 4


Correct Option: E
Explanation:

Both are true statements. A gram-positive bacterium is stained purple by the gram stain. Bacterial flagella propel the cell by using a rotating motion.

Which of the following protozoans have flagella as locomotary organ?

  1. Entamoeba histolytica
  2. G. lamblia
  3. T. cruzi
  4. L. donovani
  5. B. coli
  1. Only 1, 2 and 3

  2. Only 1, 3 and 5

  3. Only 2, 3 and 4

  4. Only 2, 4 and 5

  5. Only 3, 4 and 5


Correct Option: C
Explanation:

Giardia lamblia - Flagella Trypanosoma cruzi – Flagella Leishmania donovani – Flagella

Which of the following genera of Mollicutes exhibit pleomorphic morphology? A. Mycoplasma B. Ureaplasma C. Acholeplasma D. Anaeroplasma E. Spiroplasma

  1. Only A and B

  2. Only A and C

  3. Only B and D

  4. Only C and E

  5. Only D and E


Correct Option: B
Explanation:

This option is correct because Mycoplasma and Acholeplasma are the genera of Mollicutes that exhibit pleomorphic morphology.

Which of the following groups of bacteria are called gliding bacteria?

  1. Mycobacteria and Myxobacteria

  2. Mycobacteria and Cytophagales

  3. Myxobacteria and Cytophagales

  4. Cytophagales and Rickettsiae

  5. Rickettsiae and Chlamydiae


Correct Option: C
Explanation:

Myxobacteria and Cytophagales are called gliding bacteria on the basis of their gliding mobility on solid surfaces.

Which of the following sets contain only fruiting myxobacteria?

  1. Melittangium, Polyangium, Cystobacter

  2. Flexibacter, Sporocytophaga, Cytophyga

  3. Melittangium, Sporocytophaga, Flexibacter

  4. Cystobacter, Polyangium, Cytophyga

  5. Flexibacter, Sporocytophaga, Cystobacter


Correct Option: A
Explanation:

Cystobacter, Melittangium, Polyangium : All are fruiting myxobacteria.

Which of the following statements are incorrect about prokaryotic cell?

  1. Prokaryotic cells are smaller in size than eukaryotic cells.
  2. Site for oxidative phosphorylation is mitochondria.
  3. Ribosomal subunits are 60S and 40S.
  4. Golgi body is absent.
  1. Only 1 and 2

  2. Only 1, 2 and 3

  3. Only 2 and 3

  4. Only 2, 3 and 4

  5. Only 3 and 4


Correct Option: C
Explanation:

Mitochondria are not found in prokaryotic cells. Site for oxidative phosphorylation in prokaryotic cells is cell membrane. Cytoplasmic ribosome size of prokaryotic cells is 70S. Ribosomal subunits are 50S and 30S.

Which of the following genera of mollicutes exhibits respiratory metabolism?

  1. Acholeplasma

  2. Anaeroplasma

  3. Spiroplasma

  4. Mycoplasma

  5. Ureaplasma


Correct Option: E
Explanation:

Ureaplasma exhibits respiratory metabolism.

Which of the following sets of protozoans contain only endoparasites?

  1. Paramecium, Trypanosoma, Balantidium

  2. Paramecium, Proterospongia, Balantidium

  3. Giardia, Trypanosoma, Balantidium

  4. Proterospongia, Trypanosoma, Giardia

  5. Paramecium, Proterospongia, Giardia


Correct Option: C
Explanation:

Balantidium, Giardia, Trypanosoma: All are internal parasite protozoans. Balantidium is a common intestinal parasite of vertebrates found chiefly in amphibians and mammals. Giardia is found as parasite in the digestive tract of vertebrates. Trypanosoma is an endoparasite, which resides in blood and cerebrospinal fluid of man.

Life cycle of which of the following pathogenic protozoans is/are digenetic?

  1. E. histolytica
  2. P. vivax
  3. T. cruzi
  1. Only 1

  2. Only 1 and 2

  3. Only 1 and 3

  4. Only 2 and 3

  5. All of these


Correct Option: D
Explanation:

Plasmodium vivax (malaria parasite) completes its asexual part of life cycle in people and the sexual part in the female Anopheles mosquito (Digenetic life cycle). Trypanosam cruzi possesses a digenetic life cycle, involving a hematophagous insect vector and a mammalian host.

Which of the following statements are incorrect regarding Plasmodium vivax?

  1. Duration of exoerythrocytic cyle is 14-15 days.
  2. Duration of erythrocytic cyle is 48 hours.
  3. Incubation period is 20-24 days.
  4. Duration of sexual cycle is 10 days.
  1. Only 1 and 2

  2. Only 1 and 3

  3. Only 1 and 4

  4. Only 2 and 3

  5. Only 2 and 4


Correct Option: B
Explanation:

Duration of exoerythrocytic cyle is 8 days in Plasmodium vivax, while it is 14-15 days in Plasmodium malariae. Incubation period is 12-14 days Plasmodium vivax, while it is 20-24 days in Plasmodium malariae.

Match the columns:Column – I |Column – II| |A. E. coli|1. Amphitrichous| |B. H. pylori|2. Lophotrichous| |C. R. rubrum|3. Monotrichous| |D. V. cholerae|4. Peritrichous|

  1. A - 4, B - 3, C - 2, D - 1

  2. A - 2, B - 1, C - 4, D - 3

  3. A - 4, B - 2, C - 1, D - 3

  4. A - 3, B - 2, C - 4, D - 1

  5. A - 1, B - 2, C - 3, D - 4


Correct Option: C
Explanation:

Peritrichous bacteria have flagella projecting in all directions (e.g., Escherichia coli). Lophotrichous bacteria have multiple flagella located at the same spot on the bacteria's surfaces ( e.g., Helicobacter pylori). Amphitrichous bacteria have a single flagellum on each of two opposite ends (e.g., Rhodospirillum rubrum). Monotrichous bacteria have a single flagellum (e.g., Vibrio cholerae).

Match the column – I (Organism) with column – II (Class) ||| |---|---| |Column – I |Column – II| |A. Amoeba|1. Sporozoa| |B. Astasia|2. Mastigophora| |C. Vorticella|3. Sarcodina| |D. Leishmania|4. Ciliophora|

  1. A - 1, B - 2, C - 3, D - 4

  2. A - 2, B - 1, C - 4, D - 3

  3. A - 4, B - 1, C - 3, D - 2

  4. A - 3, B - 2, C - 4, D - 1

  5. A - 4, B - 3, C - 2, D - 1


Correct Option: D
Explanation:

Amoeba belongs to class Sarcodina. Astasia belongs to class Mastigophora. Vorticella belongs to class Ciliophora. Leishmania belongs to class Sporozoa.

Which of the following statements about prokaryotic extracellular appendages are correct?

  1. Bacterial glycocalyx is located inside the cell wall.
  2. Bacterial capsule is a well organized bacterial glycocalyx.
  3. F pili involve in transfer DNA one bacterium to another.
  4. Fimbriae help bacteria to attach to the other structures.
  1. Only 1 and 2

  2. Only 1 and 3

  3. Only 2 and 3

  4. Only 2 and 4

  5. Only 2, 3 and 4


Correct Option: E
Explanation:

Bacterial capsule is a well organised bacterial glycocalyx that is firmly attached to the bacterial cell wall. F (conjugation, sex) pili are involved in the transfer of plasmids from one bacteria to the other. Fimbriae are short pili found in large numbers and used to attach bacteria to surfaces.

Match the column – I (Protozoan) with column – II (pseudopodia) ||| |---|---| |Column – I |Column – II| |A. Amoeba|1. Lobopods| |B. Radiolaria|2. Filopods| |C. Polystomella|3. Reticulopods | |D. Actinophyrus|4. Axopods|

  1. A - 1, B - 3, C - 2, D - 4

  2. A - 3, B - 2, C - 4, D - 1

  3. A - 4, B - 3, C - 2, D - 1

  4. A - 1, B - 2, C - 3, D - 4

  5. A - 2, B - 3, C - 1, D - 4


Correct Option: D
Explanation:

Lobopods: Short, blunt, thick, fingerlike outgrowth of ectoplasm with an axial core of endoplasm, e.g., Amoeba. Filopods: Cylindrical thread like, formed entirely of ectoplasm and radiate from the body in all directions, e.g., Radiolaria. Reticulopods: Filamentous… forms a network of pods, e.g., Polystomella. Axopods: Long stiff, semi-transparent extensions of cytoplasm with pointed distal ends, e.g., Actinophyrus.  

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