Tag: biology

Questions Related to biology

The chemicals released by bacteria, which kills other bacteria are

biology the world of microbes medicinal use of microorganisms use of microorganisms in medicine vaccines

  1. Antibiotics

  2. Antibodies

  3. Antigens

  4. Allergens

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Correct Option: A
Explanation:

Antibiotic is a chemical which is released by a bacteria and inhibits the growth of other bacteria. It acts by either killing bacteria or preventing their reproduction. 

Thus, the correct answer is 'Antibiotics.'

An antibiotic, which is active against fungi is

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  1. Neomycin

  2. Terramycin

  3. Polyenes

  4. Streptomycin

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Correct Option: C
Explanation:

Antibiotics are antimicrobial substances produced by microorganisms. They are used in the treatment of bacterial infections. Examples of antibiotics include Neomycin, terramycin, Streptmomycin. Polyenes are antifungal antibiotics produced by bacterium Streptomyces species which are used to treat fungal infections. They act by changing the fungal cell membrane by complexing with sterols.

Thus, the correct answer is 'Polyenes.'

Identify a fungus with medicinal importance.

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  1. Penicillium

  2. Cercospora

  3. Agaricus

  4. Saccharomyces

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Correct Option: A
Explanation:

Penicillin is a secondary metabolite of certain species of Penicillium and is produced when the growth of the fungus is inhibited by stress. It is not produced during active growth. Production is also limited by feedback in the synthesis pathway of penicillin.

So, the correct option is 'Penicillium'.

Broad spectrum antibiotics are the ones which attack

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  1. Pathogens as well as hosts

  2. A wide range of pathogens

  3. Only a pathogen

  4. Only host

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Correct Option: B

Mode of action of Novobiocin is

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  1. Induces abnormal protein synthesis

  2. Inhibits DNA polymerisation

  3. Interferes with protein synthesis

  4. Inhibits cell wall synthesis

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Correct Option: B

The molecular structure of penicillin antibiotic is

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  1. Macrocyclic lactone

  2. Glycoside linkage in amino sugar

  3. $\beta$-lactam ring

  4. Polyaena and nonpolyaene

Show answer
Correct Option: C
Explanation:

Penicillin is obtained from Penicillium chrysogenum. Penicillin is a secondary metabolite of certain species of Penicillium and is produced when the growth of the fungus is inhibited by stress. Its structure contains β- lactam ring with a molecular structure of 339.4 g/mol. It was discovered by Alexander Fleming.

So, the correct answer is 'β- lactam ring'

Which of the following antibiotics kills bacterial cells by inhibiting the polymerisation of peptidoglycans?

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  1. Aminoglycoside

  2. Fluoroquinolones

  3. Quinine

  4. Penicillin

Show answer
Correct Option: D
Explanation:

Penicillin is a secondary metabolite of certain species of Penicillium and is produced when the growth of the fungus is inhibited by stress. It is not produced during active growth. Production is also limited by feedback in the synthesis pathway of penicillin. It was discovered by Alexander Fleming.

So, the correct option is 'Penicillin.

Some antibiotics act ionospheres, which means that they ______________________.

biology the world of microbes medicinal use of microorganisms use of microorganisms in medicine vaccines

  1. Interfere directly with bacterial cell wall synthesis

  2. Increase cell membrane permeability to specific ions

  3. Inhibit both transcription and translation

  4. Inhibit electrophoresis separation of ions

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Correct Option: A

Microorganisms are our friends and foes. Some of them are useful for us while some of them are harmful. From the given list sort out useful and harmful actions of microorganisms.
Production of antibiotics, food spoiling, curd preparation, vaccine production, citrus canker.

biology the world of microbes medicinal use of microorganisms use of microorganisms in medicine vaccines

  1. Useful: Curd preparation, citrus canker, production of antibiotics

    Harmful: Food spoiling, vaccine production

  2. Useful: Production of antibiotics, curd preparation, vaccine production

    Harmful: Food spoiling, citrus canker

  3. Useful: Citrus canker, vaccine production, curd preparation

    Harmful: Food spoiling, production of antibiotics

  4. Useful: Vaccine production, curd preparation

    Harmful: Food spoiling, citrus canker, production of antibiotics

Show answer
Correct Option: B
Explanation:
An antibiotic is a chemical substance that inhibits the growth of bacteria. They hinder the reproductive cycle of the bacteria inside the body of the host.
Lactobacillus is a genus of bacteria, which can convert sugars into lactic acid by means of fermentation. 
A vaccine is a biological preparation that provides active acquired immunity to a particular disease. It has killed or weakened suspension of microorganism which generates the immune response.
Citrus canker is a disease affecting citrus species caused by the bacterium Xanthomonas axopods. The infection causes lesions on the leaves, stems, and fruit of citrus trees, including lime, oranges, and grapefruit. 

Micorganism like fungus releases toxins which spoils the food.
So, the correct answer is option B.

An antibody is best described as

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  1. A particle

  2. An organism

  3. A molecule

  4. A fragment

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Correct Option: C
Explanation:

An antibody is commonly known as an immunoglobulin (Ig). It is a large, Y-shape protein molecule produced by plasma cells in response to the antigen.

So, the correct answer is option C.