Tag: microbiology: organisms in industry

Questions Related to microbiology: organisms in industry

A culture of Mycobacterium leprae was subjected to alkaline ethanol extraction prior to acid-fast staining. The colour of the culture following staining will be

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Red

  2. Green

  3. Yellow

  4. Blue

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Correct Option: A
Explanation:
A culture of Mycobacterium leprae was subjected to alkaline ethanol extraction prior to acid-fast staining. The colour of the culture following staining will be red because it is an acid-fast bacteria as it contains a large amount of lipoidal material in their cell wall which prevents penetration of decolorizing solution.

So, the correct answer is 'Red'.

Gram positive bacteria are more rigid than Gram negative bacteria because of the 

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. presence of multiple layers of peptidoglycan

  2. lack of D-amino acids in their cell wall

  3. presence of N-acetylgalactosamine in the peptidoglycan backbone

  4. presence of lipopolysaccharide

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Correct Option: A
Explanation:
Because gram-positive bacteria are surrounded by layers of peptidoglycan which is many times thicker than is found in the gram negatives. Gram-negative bacteria are surrounded by a thin peptidoglycan cell wall, which is surrounded by an outer membrane containing lipopolysaccharide which is not present in gram-positive bacteria.

So, the correct answer is 'presence of multiple layers of peptidoglycan'.

Mesosomes were taken as

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Golgi bodies

  2. Plastids

  3. Mitochondria

  4. Endoplasmic recticulum

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Correct Option: C
Explanation:

In the vesicle of mesosomes, the respiratory enzymes and the components of electron transport such as ATPase, dehydrogenase, cytochrome are present in low amount. So, they were considered anologous to mitochondria for their respiratory function. 

So, the correct option is 'Mitochondria'.

Which of the following statements is false?

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Bacteria glycocalyx differ in composition and thickness among diffrent bacteria.

  2. Bacterial envelope has a layered structure and each layer has a distinct function but they act as a single structure

  3. Bacteria are organelle less and contains ribosomes

  4. Number and arrangements of flagella is variable in bacteria.

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Correct Option: A

____________ is a microbial bio-control agent.

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Pseudomonas

  2. Penicillium

  3. Bacillus thuringiensis

  4. Clostridium

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Correct Option: A
Explanation:

Pseudomonas are aerobic, gram-negative bacteria, ubiquitous in agricultural soils, and are well adapted to growing in the rhizosphere. Pseudomonads possess many traits that make them well suited as biocontrol and growth-promoting agents. 

The large holes in "swiss-cheese" are due to production of large amount of $CO _2$ by a bacterium named?

botany option b: biotechnology and bioinformatics gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Lactobacillus

  2. Saccharomyces cerevisiae

  3. Propionibacterium sharmani

  4. Streptococcus

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Correct Option: A

Teichoic acid is present in 

botany living world and classification of microbes gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Gram +ve bacteria

  2. Gram -ve bacteria

  3. Spirochaete

  4. Actinomycetes

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Correct Option: A
Explanation:

Teichoic acids are found within the cell wall of Gram-positive bacteria. The main function of teichoic acid is to provide rigidity to the cell wall by attracting cations, such as magnesium and sodium.

Which one of the following dyes cannot be used for staining chromatin material?

botany living world and classification of microbes gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Acetocarmine

  2. Crystal violet

  3. Haematoxylin

  4. Schiff's reagent (Feulgen stain)

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Correct Option: B
Explanation:

Crystal violet dye is used as a histological stain and in Gram's method of classifying bacteria.
Rest all other dyes in option as acetocarmine, haematoxylin and Schiff's reagent are used to stain chromosome.
Thus, the correct answer is option B.

All the following statements are true about exotoxins except 

botany living world and classification of microbes gram staining microbiology: organisms in industry cell wall and cell membrane

  1. They are protein in nature.

  2. Are heat labile.

  3. Produced by Gram + positive bacteria.

  4. Are highly antigenic.

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Correct Option: C
Explanation:

An exotoxin is a toxin secreted by bacteria. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. Exotoxin is secreted during lysis of the cell. 

The main difference between Gram +ve and Gram -ve resides in the composition of 

botany living world and classification of microbes gram staining microbiology: organisms in industry cell wall and cell membrane

  1. Cilia

  2. Cell wall

  3. Cell membrane

  4. Cytoplasm

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Correct Option: B
Explanation:

The Gram-negative cell wall is characterized by presence of outer membrane, a thinner peptidoglycan layer and extensive periplasmic space surrounding the peptidoglycan. The uppermost layer of the outer membrane has lipopolysaccharide, while the innermost layer is a typical lipid layer. Presence of membrane channels formed by porin proteins in outer membrane impart make them less penetrable as compared to Gram positive cells. Gram positive cells are characterized by presence of single thick layer of cell wall which is made up of peptidogycan, teichoic acid and lipoteichoic acid. They lack outer membrane and porin and have narrow periplasmic space. Plasma membrane is the unit membrane in both, Gram positive and Gram negative bacteria, present beneath cell wall with primarily phospholipids (making up about 30–40% of the membrane mass) and proteins (60–70%). The dense gelatinous solution surrounded by plasma membrane is cytoplasm which has same composition in both, Gram positive and Gram negative cells. Cilia are the eukaryotic structures which are absent in bacteria as they are prokaryotic. 

Thus, the correct answer is option B.