MCQ on Microbiology: Introduction & Explanation

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Jasmine Grover

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Microbiology corresponds to the study of smaller living organisms visible only under a microscope. The scientific study of microbiology includes unicellular, multicellular, and acellular microorganisms, for example, bacteria, fungi, viruses, etc. (collectively known as microbes). The effect of microbes on living beings is vast as they are responsible for several functions in our environment, which includes agriculture, the human body, climate, etc. Scientists have taken the advantage of the versatility of these microbes and prepared life-saving drugs. Various phenomena in the world rely on microbes, such as biodegradation, diseases, climate change, nutrient cycling, etc. Microbiology helps to figure out the diversity of life on Earth. We can figure out the ways to control population, pollution, and climate change using the study of Microbiology. It has a big role to play in the health care of the human body as doctors and biologists study microbiology to check blood, urine or any sort of samples. 


Ques. Who is considered the father of Microbiology?

  1. Ferdinand Cohn
  2. Antoni van Leeuwenhoek 
  3. Louis Pasteur
  4. Joseph Lister

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Ans: b) Antoni van Leeuwenhoek

Explanation: Antoni van Leeuwenhoek is considered the father of microbiology. He was a businessman and scientist as well in the Golden era of Dutch Technology and Science. He is considerably self-taught, who discovered bacteria and protists. Leeuwenhoek experimented with his own design microscopes and made his observations.

Ques. Which of the following contain Phosphorus as its prominent component?

  1. Teichoic Acid
  2. Nucleotides
  3. Both a and b
  4. Neither a nor b

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Ans: c) Both a and b (Teichoic Acid and Nucleotides) 

Explanation: Phosphorus is a prominent component of Teichoic Acid and Nucleotides present in the form of phosphate. Teichoic acid corresponds to the group of glycopolymers that consist of glycosyl phosphate, glycerol phosphate, and ribitol phosphate. The nucleotide consists of a sugar molecule that is attached to a phosphate group having a base that contains nitrogen.

Ques. Bacteria’s respiratory chain is connected with_______

  1. Cell wall
  2. Cytoplasmic wall
  3. Mitochondrial membrane
  4. Cytoplasmic membrane

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Ans: d) Cytoplasmic membrane

Explanation: Most of the bacterias have the respiratory chain connected with the cytoplasmic membrane. The electron transport is done by the system of dehydrogenases and cytochromes. The respiratory chain is responsible for the catalyzation in the oxidation of fuel molecules and also, in the transfer of electrons to molecular oxygen. 

Ques.  _______ is a Spirochetes.

  1. Treponema Pallidum
  2. Streptomyces sp.
  3. Corynebacterium Diphtheriae
  4. Spirillum Volutans

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Ans: a) Treponema Pallidum 

Explanation: Spirochetes correspond to motile, gram-negative and spiral bacteria, having endocellular flagella which makes them authentic. They are considered to be flexible as they can twist and screw up their shapes. Treponema Pallidum is related to the spirochetes group and has different subspecies responsible for diseases like bejel, yaws and syphilis

Ques. Which one of the following corresponds to the bacteria that has clusters of flagella at both the poles of cells?

  1. Lophotrichous
  2. Peritrichous
  3. Amphitrichous
  4. Monotrichous

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Ans: c) Amphitrichous 

Explanation: The flagella occur at one end or at both sides in the form of clusters in Amphitrichous.

The cluster of polar flagella corresponds to the Lophotrichous.

Lateral flagella surround the Peritrichous.

Single polar flagella correspond to the Monotrichous.

Ques. The approximate size of a bacterial cell is:

  1. 1.5 micrometre in diameter
  2. 1 micrometre in diameter
  3. 2 micrometre in diameter
  4. 0.5 to 1.0 micrometre in diameter

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Ans: d) 0.5 to 1.0 micrometer in diameter

Explanation: Bacterial cells are comparatively very small in size. Experiments and observations have proven that the diameter of a bacteria cell is from 0.5 to 1.0 micrometres. You can only observe or see bacteria under a microscope and not with the naked eye.

Ques. __________ does not correspond to an ammonia-oxidizing bacteria.

  1. Nitrosococcus Oceanus
  2. Nitrospina Gracilis
  3. Nitrosomonas Europaea
  4. Nitrosovibrio Tenuis

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Ans:: b) Nitrospina Gracilis

Explanation: Nitrosovibiro Tenuis, Nitrosomonas Europaea, and Nitrosococcus Oceanus are ammonia-oxidizing bacteria whereas Nitrospina Gracilis is considered to be a nitrite-oxidizing bacteria that oxidises nitrite to nitrate. 

Ques. Which enzyme is responsible for the degradation of cellulose to cellobiose?

  1. beta-glucosidase
  2. Cellulase
  3. cellulose dehydrogenase
  4. Hexokinase

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Ans: b) Cellulase

Explanation: Cellulase is present in abundant amounts in plants, and is responsible for the degradation of cellulose into cellobiose. Cellulase initialises the enzymatic attack which consequently splits the long-chain glucose polymer into cellobiose which has two glucose units.

Ques. What is the salt concentration at which microorganisms from lakes and rivers can grow?

  1. Below 1 percent
  2. Above 1 percent
  3. 3 to 4 percent
  4. 4 percent

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Ans: a) Below 1 percent

Explanation: The microorganisms from lakes and rivers are very sensitive to salts and they will not be able to grow at more than 1 percent of salt concentration. There exist salt-loving bacterias that can survive higher salt concentrations. These are considered halophilic bacteria.

Ques. Microorganism that is eliminated in canned foods is ________.

  1. Clostridium botulinum
  2. Lactobacillus
  3. Mycobacterium tuberculosis
  4. Coxiella burnetii

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Ans: a) Clostridium botulinum

Explanation: Clostridium Botulinum (a spore-forming anaerobe) is one of the prominent microorganisms that have to be eliminated from canned foods because they are potentially capable of producing a highly potent lethal toxin. 

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