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Microbiology

Description: GATE: LS: Microbiology
Number of Questions: 20
Created by:
Tags: Microbiology Microbial Taxonomy and Diversity
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Which of the following viruses cause tumor in humans?

  1. Epstein Barr virus

  2. HIV

  3. Papilloma virus

  4. Varicella-Zoster virus

  5. Phage virus


Correct Option: C
Explanation:

There are only two types of viruses that have been proved to be responsible for tumors in humans. They are Tcell lymphoma/ leukaemia virus(HTLV) and papillomavirus.

Pseudomurein present in methanogenic archaea is ______ in nature.

  1. peptidoglycan

  2. cellulose

  3. polystyrene

  4. polychloropene

  5. Polypropylene


Correct Option: A
Explanation:

Without the constraints of the conserved molecule peptidoglycan, archaeal cell wall may be quite diverse. Methanogenic archaea possesses pseudomurein [Peptidoglycan like polymer which is cross linked with L –Amino acids].

Nature of Aquifex species is:

  1. thermophilic

  2. halophilic & autolithotrophic

  3. chemolithoautotrophic

  4. both 1 & 3

  5. lithotrophic


Correct Option: D
Explanation:

Aquifex species is thermophilic as well as chemolithoautotroph that captures energy by oxidizing the hydrogen, sulfur, thiosulfate with oxygen as the terminal electron acceptor. Original bacterial ancestor is thermophilic & chemolithoautotrophic.

Rhizopus stolonifer belongs to:

  1. Ascomycetes

  2. Deuteromycetes

  3. Zygomycetes

  4. Oomycetes

  5. Myxomycetes


Correct Option: C
Explanation:

It belongs to Zygomycetes as it synthesizes chitosan where other fungi have chitin as structural polysachharide. Chitosan is deacetylated homopolymer of chitin.

Moldy fungi differ from the slime molds in:

  1. possessing basidiospore

  2. producing amoeboid or flagellated cells

  3. being heterotrophic

  4. having different cellular organisation

  5. there is no difference


Correct Option: C
Explanation:

Moldy fungi are absorptive heterotrophs, whereas the slime molds perform phagocytosis, a process in which they engulf their food and get it digested through different enzymes.

The spreading factor responsible for Streptococci infection is:

  1. streptokinase

  2. muramic acid

  3. deoxyribonuclease C

  4. peptidoglycan

  5. none of the above


Correct Option: C
Explanation:

Deoxyribosenuclease 3 is an extracellular enzyme produced by Streptococci [Gr.p A]. It is spreading factor, an important enzyme in skin and soft tissue infection.

Which of the following fungi is heteroecious?

  1. Puccinia

  2. Ustilago

  3. Rhizopus

  4. Yeast

  5. Mucor


Correct Option: A
Explanation:

It is a heteroceous fungi genus that needs two host, one is primary and another secondary. Both the primary host and an alternate unrelated host are required for the parasite to complete the life cycle.

The causative agent belongs to which of the following protozoan subclass?

A patient with fever, chronic diarrhea, malabsorptions came to visit the doctor. He was detected with H.I.V. earlier.

  1. Coccidia

  2. Apicomplexa

  3. Protista

  4. Microsporidea

  5. Ciliates


Correct Option: A
Explanation:

Isospora belongs to it. Coccidia are a subclass of spore forming, microscopic, single celled obligatory intracellular parasites.

The agent of amoebic dysentery is:

Amoebic dysentery is a frequently occuring disease in humans and other primates. It especially occurs in the tropical areas. If it is not treated timely, it may be serious and in some cases fatal.

  1. Entamoeba histolytica

  2. Toxoplasma

  3. Staphylococcus

  4. Dinoflagellates

  5. Trypanosoma evansi


Correct Option: A
Explanation:

Entamoeba histolytica is an anaerobic, protozoan parasite. It predominantly infects human and other primates.

Which of the following is the causative agent of the ailments?

A patient with fever, chronic diarrhea, malabsorptions came to visit the doctor. He was detected with H.I.V. earlier.

  1. Entamoeba histolytica

  2. Toxoplasma gondii

  3. Streptococcus

  4. Isospora

  5. Giardia


Correct Option: D
Explanation:

Isospora is an internal parasite. It causes acute, non-bloody diarrhea in H.I.V patients and other immunocompromised individuals.

Match the follwing:

 
a. Fool's mushroom 1. Galerina marginata
b. False morel 2. Gyromitra esculenta
c. Autumn Skull Cap 3. Amanita verna
d. Sulfur tuft 4. Hypholoma fasciculare
  1. a - 3, b - 2, c - 1, d - 4

  2. a - 1, b - 3, c - 2, d - 4

  3. a - 2, b - 4, c - 3, d - 1

  4. a - 4, b - 3, c - 1, d - 2

  5. a - 3, b - 2, c - 4, d - 1


Correct Option: A
Explanation:

Fool’s mushroom is Amanita verna, Galerina marginata is called false morel, Autumn skull cap is Galerina or deadly Galerina, and Hypholoma is called as Sulfur Tuft.

Which of the following units is used to measure bacterial growth?

Bacterial growth is the division of one bacterium into two daughter cells in a process called binary fission.

  1. IU/L

  2. mM fraction

  3. O.D

  4. cfu/ml

  5. cell/colony


Correct Option: C
Explanation:

O.D, i. e., optical density. In spectroscopy, the absorbance, i.e., optical density of a material is a logarithmic ratio of the radiation falling upon a material to the radiation transmitted through a material. Measurements of absorbance are carried out in analytical chemistry. This measures the rate of growth of a bacterial culture.

Match the following:

 
a. Chinese Liver Fluke 1. Paragonimus
b. Lung Fluke 2. Opisthorchisc
c. Parasitic pneumonia 3. Enterobius
d. Pinworm 4. Ascaris
  1. a - 1, b - 2, c - 4, d - 3

  2. a - 2, b - 3, c - 1, d - 4

  3. a - 1, b - 3, c - 4, d - 2

  4. a - 2, b - 1, c - 4, d - 3

  5. a - 2, b - 4, c - 1, d - 3


Correct Option: D
Explanation:

Opisthorchish is called Chinese Liver fluke, Paragonimus is called Lung Fluke, ascaris causes parasitic pneumonia and Enterobius is called pinworm.

Match the following:

a. Stachybotrys atra 1. Indoor mold
b. Aspergillus niger 2. Textile
c. Bipolaris 3. Black mold
d. Ulocladium 4. Food decaying
  1. a - 3, b - 4, c - 1, d - 2

  2. a - 4, b - 3, c - 2, d - 1

  3. a - 3, b - 1, c - 4, d - 2

  4. a - 1 , b - 4, c - 3, d - 2

  5. a - 2, b - 3, c - 4, d - 1


Correct Option: C
Explanation:

Stachybotrys atra is a black mold, Aspergillus niger is an indoor mold, Bipolaris decays foods, and Ulocladium is related to textiles.

HPV infection is mainly limited to:

Human papilloma virus is capable of infecting humans.

  1. squamous epithelium

  2. cuboidal epithelium

  3. columnar epithelium

  4. stratified epithelium

  5. All of the above


Correct Option: D
Explanation:

HPV infection is limited to the basal cells of stratified epithelium, the only tissue in which they replicate. HPV cannot bind to live tissue; it infects epithelial tissues through micro-abrasions or other epithelial trauma that exposes segments of the basement membrane.

The pathogenic stage of the agent causing amoebic dysentery:

Amoebic dysentery is a frequently occuring disease in humans and other primates. It especially occurs in the tropical areas. If it is not treated timely, it may be serious and in some cases fatal.

  1. merozoite

  2. Sporozoite

  3. trophozoite

  4. Cilia

  5. none of the above


Correct Option: C
Explanation:

It is the active stage, and exists only in host and in fresh faeces. Cysts survive outside the host in water, in soils and on foods, especially under moist conditions.

Match the following

 
P. Acetogenesis 1. Ability of an organism to use C1 compounds as the source of energy
Q. Annamox 2. Uses H2 as an electron donor and CO2 as an electron acceptor
R. Syntrophy 3. Anaerobic ammonia oxidation
S. Methylotrophy 4. Pairing of multiple species to achieve a chemical reaction
  1. P-1, Q-2, R-3, S-4

  2. P-2, Q-3, R-4, S-1

  3. P-4, Q-3, R-1, S-3

  4. P-1, Q-4, R-4, S-2

  5. P-2, Q-1, R-4, S-3


Correct Option: B
Explanation:

 Correct answer- 2) Acetogenesis is a type of microbial metabolism that uses hydrogen (H2) as an electron donor and carbon dioxide (CO2) as an electron acceptor to produce acetate. Bacteria that can synthesize acetate autotrophically are called homoacetogens. Carbon dioxide reduction in all homoacetogens occurs by the acetyl-CoA pathway. This pathway is also used for carbon fixation by autotrophic sulfate-reducing bacteria and hydrogenotrophic methanogens. Often homoacetogens can also be fermentative, using the hydrogen and carbon dioxide produced as a result of fermentation to produce acetate, which is secreted as an end product. Anammox stands for anaerobic ammonia oxidation and the organisms responsible were relatively Annamox means anaerobic ammonia oxidation. This metabolism occurs in members of Plactomycetes (e.g. Brocadia annamoxidans) and involves coupling of ammonia oxidation to nitrate reduction. Annamox organisms are autotrophs and can fix CO2. Due to this property, these organisms can be used in industry to remove nitrogen in wastewater treatment processes. Syntrophy is the pairing of multiple species occurs in order to achieve chemical reaction which on its own will be energetically unfavorable. In Syntrophomonas, alone, the oxidation of butyrate to acetate and hydrogen gas is energetically unfavorable. But, when a hydrogenotrophic (hydrogen-using) methanogen is present the use of the hydrogen gas will significantly lower the concentration of hydrogen (down to 10−5 atm) and thereby shift the equilibrium of the butyrate oxidation reaction under standard conditions (ΔGº’) to non-standard conditions (ΔG’). Methylotrophy refers to the ability of an organism to use C-1 compounds as energy sources. These compounds are methanol, methyl amines, formaldehyde and formate. Several other less common substrates may also be used for metabolism, all of which lack carbon-carbon bonds. Examples are, bacteria Methylomonas and Methylobacter.

Match the following:

 
a. Rabies 1. Mantoux test
b. TB 2. FTA-ABS
c. Cryptococcus neoformans 3. Negri bodies
d. Treponema pallidum 4. Maltese cross
  1. a - 3, b - 4, c - 2, d - 1

  2. a - 3, b - 1, c - 4, d - 2

  3. a - 3, b - 4, c - 1, d - 2

  4. a - 2, b - 4, c - 1, d - 3

  5. a - 2, b - 4, c - 3, d - 1


Correct Option: B
Explanation:

Negri bodies are large, pathogenic, cellular inclusions found in the cytoplasm of nerve cells containing rabies virus. Negri bodies consist of nuclear proteins produced by the virus. Mantoux is a tuberculin sensitivity test, it is a screening test for T.B.  Maltese crosses are anisotropic fat droplets, related to finely granulated renal casts. Maltese cross fluorescence is seen in case of Cryptococcus. FTA ABS test is blood test tool for detecting antibodies to the bacteria Treponema pallidum that causes syphilis. A positive screening indicates syphilis infection.

Like all other papilloma viruses, HPV causes productive infections only in:

Human papilloma virus is capable of infecting humans.

  1. muscle tissues

  2. keratinocytes of skin or mucous membrane

  3. bone marrow cells

  4. squamous cells

  5. leucocytes


Correct Option: B
Explanation:

Like all papillomma viruses, HPV produces infections only in keratinocytes of skin or mucous membrane. HPV infection is limited to the basal cells of stratified epithelium, the only tissue in which they replicate. HPV cannot bind to live tissues; it infects epithelial tissues through micro-abrasions or other epithelial trauma that exposes segments of the basement membrane.

Bacterial growth may be suppressed with:

Bacterial growth is the division of one bacterium into two daughter cells in a process called binary fission.

  1. bacteriostats

  2. auxostats

  3. turbidostat

  4. biostat

  5. chemostat


Correct Option: A
Explanation:

Bacteriostats are biological or chemical agents which stop bacteria from reproducing, but not necessarily harming them.

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