Microbiology Miscellaneous


Microbiology Miscellaneous

  1. Match the products in Group I with the microbial cultures in Group II used for their industrial production ​​
    Group I​​​ Group II
    P.​ Gluconic acid​ 1. ​Leuconostoc ​​​​​mesenteroids
    Q.​ L – Lysine​ 2.​ Aspergillus niger
    ​​R.​ Dextran​ 3.​ Brevibacterium flavum​
    ​​S.​ Cellulase​ 4.​ Trichoderma reesei ​










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    Microbial species such as Aspergillus Niger have been utilized in many researches of gluconic acid fermentation. ​​
    Strains of Brevibacterium flavum are used for the synthesis of L- lysine. ​​
    Dextran is synthesized from sucrose by certain lactic-acid bacteria, the best-known being Leuconostoc mesenteroides and Streptococcus mutans. ​​Trichoderma reesei is an industrially important cellulolytic filamentous fungus. T. reesei has the capacity to secrete large amounts of cellulolytic enzymes (cellulases and hemicellulases).

    Correct Option: C

    Microbial species such as Aspergillus Niger have been utilized in many researches of gluconic acid fermentation. ​​
    Strains of Brevibacterium flavum are used for the synthesis of L- lysine. ​​
    Dextran is synthesized from sucrose by certain lactic-acid bacteria, the best-known being Leuconostoc mesenteroides and Streptococcus mutans. ​​Trichoderma reesei is an industrially important cellulolytic filamentous fungus. T. reesei has the capacity to secrete large amounts of cellulolytic enzymes (cellulases and hemicellulases).


  1. Match Group I with Group II ​​
    Group I​​​ Group II
    P.​ Staphylococcus aureus​ 1.​ Biofilms
    Q.​ Candida albicans​ 2.​ Bacteriocins
    ​​R.​ Mycobacterium ​ 3.​ Methicillin ​​​tuberculosis​​ resistance
    S. ​Lactobacillus lactis​ 4.​ Isoniazid
    ​​ ​​









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    Methicillin-resistant Staphylococcus aureus (MRSA) are a type of staphylococcus or “staph” bacteria that are resistant to many antibiotics. Staph bacteria, like other kinds of bacteria, normally lives on skin and in nose, usually without causing problems. MRSA is different from other types of staph because it cannot be treated with certain antibiotics such as methicillin (as it is methicillin resistant). ​​Biofilms formed by Candida albicans are resistant towards most of the available antifungal drugs. Therefore, infections associated with Candida biofilms are considered as a threat to immunocompromised patients. Also, the fungal pathogen Candida albicans is frequently associated with catheter-based infections
    infections because of its ability to form resilient biofilms. ​​Isoniazid is an organic compound that is the first-line medication in prevention and treatment of tuberculosis. Isoniazid is a prodrug and must be activated by a bacterial catalase-peroxidase enzyme that in Mycobacterium tuberculosis is called KatG.
    ​​Bacteriocins are the bioactive peptides produced by certain bacteria like lactobacillus lactis that inhibit the growth of other bacteria. It is a gram positive bacterium used in the production of milk and cheese. ​

    Correct Option: C

    Methicillin-resistant Staphylococcus aureus (MRSA) are a type of staphylococcus or “staph” bacteria that are resistant to many antibiotics. Staph bacteria, like other kinds of bacteria, normally lives on skin and in nose, usually without causing problems. MRSA is different from other types of staph because it cannot be treated with certain antibiotics such as methicillin (as it is methicillin resistant). ​​Biofilms formed by Candida albicans are resistant towards most of the available antifungal drugs. Therefore, infections associated with Candida biofilms are considered as a threat to immunocompromised patients. Also, the fungal pathogen Candida albicans is frequently associated with catheter-based infections
    infections because of its ability to form resilient biofilms. ​​Isoniazid is an organic compound that is the first-line medication in prevention and treatment of tuberculosis. Isoniazid is a prodrug and must be activated by a bacterial catalase-peroxidase enzyme that in Mycobacterium tuberculosis is called KatG.
    ​​Bacteriocins are the bioactive peptides produced by certain bacteria like lactobacillus lactis that inhibit the growth of other bacteria. It is a gram positive bacterium used in the production of milk and cheese. ​



  1. Which one of the following DOES NOT belong to the domain of Bacteria? ​​









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    Besides cyanobacteria, all the others named were typically sharing the common feature belonging to bacteria domain – i.e. oxygen intolerance. However, cyanobacterium is a phylum which obtains energy through photosynthesis by performing oxygenic photosynthesis and reducing the atmosphere into an oxidising one. The ability to undergo oxygenic reactions distinctly distinguishes cyanobacteria from other bacterial domains. Thereby, cyanobacteria play a very important role in initiating biodiversity and are believed to evolve into plant chloroplast and eukaryotic algae by the process of endosymbiosis. Cyanobacterium due to its stand-out property of oxygenic photosynthesis in an oxygenic environment is thus distinct from other preferably an-oxygenic bacterial domains. ​

    Correct Option: A

    Besides cyanobacteria, all the others named were typically sharing the common feature belonging to bacteria domain – i.e. oxygen intolerance. However, cyanobacterium is a phylum which obtains energy through photosynthesis by performing oxygenic photosynthesis and reducing the atmosphere into an oxidising one. The ability to undergo oxygenic reactions distinctly distinguishes cyanobacteria from other bacterial domains. Thereby, cyanobacteria play a very important role in initiating biodiversity and are believed to evolve into plant chloroplast and eukaryotic algae by the process of endosymbiosis. Cyanobacterium due to its stand-out property of oxygenic photosynthesis in an oxygenic environment is thus distinct from other preferably an-oxygenic bacterial domains. ​


  1. Under stress conditions bacteria accumulate









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    Stress is a stringent response that occurs in bacteria due to amino acid starvation or fatty acid limitation. Other reasons involve heat shock or iron limitation. This response is signalled by p/ppGpp as an alarmone. It causes diversion of resources away from growth of cells towards the quenching of stress by promoting amino acid synthesis for enhancing survival. It continues until nutrients are restored. p/ppGpp causes inhibition of RNA synthesis in cases of AA shortage. It results in AA conservation by decreasing the translational machinery. Another mechanism of p/ppGpp action is the upregulation of genes for AA uptake and biosynthesis. It functions by influencing overall gene expression pattern for survival in stress conditions.

    Correct Option: C

    Stress is a stringent response that occurs in bacteria due to amino acid starvation or fatty acid limitation. Other reasons involve heat shock or iron limitation. This response is signalled by p/ppGpp as an alarmone. It causes diversion of resources away from growth of cells towards the quenching of stress by promoting amino acid synthesis for enhancing survival. It continues until nutrients are restored. p/ppGpp causes inhibition of RNA synthesis in cases of AA shortage. It results in AA conservation by decreasing the translational machinery. Another mechanism of p/ppGpp action is the upregulation of genes for AA uptake and biosynthesis. It functions by influencing overall gene expression pattern for survival in stress conditions.



  1. Gas vacuoles are present in ​​









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    Gas-vacuoles consisting of collections of gas-cylinders, and continuity of the plasma membrane with lamellae, are observed at all stages of growth of Anabaena flos-aquae. It is known to produce endotoxins, the toxic chemicals released when cells die. Once released (lysed), and ingested, these toxins can damage liver and nerve tissues in mammals.

    Correct Option: A

    Gas-vacuoles consisting of collections of gas-cylinders, and continuity of the plasma membrane with lamellae, are observed at all stages of growth of Anabaena flos-aquae. It is known to produce endotoxins, the toxic chemicals released when cells die. Once released (lysed), and ingested, these toxins can damage liver and nerve tissues in mammals.