Tag: microbiology: organisms in industry

Questions Related to microbiology: organisms in industry

How many layers are there in the cell envelope of Gram (-) ve bacteria?

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

  1. 2

  2. 3

  3. 4

  4. 6

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Correct Option: B

Gram staining procedure of bacteria is based upon the properties of

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

  1. Cell membrane

  2. Cell wall

  3. Capsule

  4. DNA.

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Correct Option: B

Choose the correct answers from the alternatives given.
Eubacterial cell walls are composed of ........., and a sticky mesh of polysaccharides, a ......... often surrounds the wall

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

  1. peptidoglycan, plasma membrane

  2. cellulose; glycocalyx

  3. cellulose; plasma membrane

  4. peptidoglycan; glycocalyx

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Correct Option: D
Explanation:

Eubacterial cell walls are composed of peptidoglycan and a sticky mesh of polysaccharides, a glycocalyx often surrounds the wall.

So, the correct option is 'peptidoglycan; glycocalyx'.

Some gram $-$ve bacteria have peptidoglycan and an extra layer of.

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

  1. Lipo polysaccharide

  2. Lipo-protein

  3. Protein

  4. Both A and C

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Correct Option: A
Explanation:
Both Gram negative and Gram positive bacteria have a peptidoglycan layer in the cell wall. Peptidoglycan is also called as mucopeptide. It is a polymer that is made up of sugars and amino acids. Gram positive bacteria have thick layer of peptidoglycan. However, Gram negative bacteria have thin layer of peptidoglycan. Apart from this, Gram negative bacteria have outer wall made up of lipopolysaccharide.
Thus, the correct answer is 'Lipo polysaccharide.'

Choose the correct answers from the alternatives given.
In comparison to Gram -ve bacteria, Gram +ve bacteria

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

  1. have less peptidoglycan

  2. have more complex cell walls

  3. retain the crystal violet dye

  4. are more resistant to antibiotics

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Correct Option: C
Explanation:

Gram-positive bacteria are stained dark blue or violet by Gram staining. This is in contrast to gram-negative bacteria, which take up the counterstain and appear red or pink. 

So, the correct option is 'retain the crystal violet dye'.

State whether the following statements are true or false.
When treated with crystal violet and subsequently with iodine some bacteria remain colourless and these are called gram +ve bacteria.

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

  1. True

  2. False

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Correct Option: A
Explanation:

When treated with crystal violet and subsequently with iodine, some bacteria remain colorless and these are called gram +ve bacteria.

So, the correct option is 'True'.

State whether the following statements are true or false.
Gram stain which is extracted from gram pods is used to differentiate Gram -ve and Gram +ve bacteria.

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

  1. True

  2. False

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Correct Option: A
Explanation:

Gram stain is the most important staining procedure. Gram-positive bacteria stain purple, whereas gram-negative bacteria stain pink. 

So, the correct option is 'True'.

Arrange the following steps in a correct sequence as per Gram's staining technique:

Treatment with $0.5$% iodine solution $(1)$, washing with water $(2)$, treatment with absolute alcohol/ acetone $(3)$, staining with weak alkaline solution of crystal violet $(4)$.

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

  1. $4\rightarrow 1 \rightarrow 2\rightarrow 3$

  2. $3\rightarrow 2 \rightarrow 1\rightarrow 4$

  3. $3\rightarrow 1 \rightarrow 2\rightarrow 4$

  4. $4\rightarrow 2 \rightarrow 3\rightarrow 1$

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Correct Option: A
Explanation:

Bacteria can be classified into two groups based upon reaction of bacteria to Gram's stain (Christian Gram, $1884$). Bacteria are first stained with weakly alkaline solution of crystal violet and then treated with $0.5$% iodine solution. This is followed by washing with water and then with alcohol or acetone. Bacteria which retain blue or purple colour are known as Gram $(+)$ bacteria (e.g., Bacillus subtilis). Bacteria which do not retain stain and become colourless are called Gram $(-)$ bacteria (e.g., Escherichia coli). Washing of the stain in Gram $(-ve)$ bacteria is due to high lipid content of their cell wall which gets dissolved in organic solvents like acetone.

So, the correct answer is '$4\rightarrow 1 \rightarrow 2\rightarrow 3$'.

Select the correct option:

Which of the given statements are correct?
(i) Bacillus subtilis is a Gram $(+)$ bacteria.
(ii) Escherichia coli is a Gram $(-)$ bacteria.
(iii) Washing of the Gram's stain in Gram $(-)$ bacteria is due to high lipid content of the cell wall, which gets dissolved in organic solvent like acetone.

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

  1. (i) and (ii)

  2. (ii) and (iii)

  3. (i) and (iii)

  4. (i), (ii) and (iii)

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Correct Option: D
Explanation:

Bacteria can be classified into two groups based upon reaction of bacteria to Gram's stain (Christian Gram, $1884$). Bacteria are first stained with weakly alkaline solution of crystal violet and then treated with $0.5$% iodine solution. This is followed by washing with water and then with alcohol or acetone. 

Bacteria which retain blue or purple colour are known as Gram $(+)$ bacteria (e.g., Bacillus subtilis). 
Bacteria which do not retain stain and become colourless are called Gram $(-)$ bacteria (e.g., Escherichia coli). Washing of the stain in Gram $(-ve)$ bacteria is due to high lipid content of their cell wall which gets dissolved in organic solvents like acetone.
So, the correct answer is '(i), (ii) and (iii)'.

Glycocalyx (mucilage sheath) of a bacterial cell may occur in the form of a loose sheath called _____ or it may be thick and tough called _____.

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

  1. Capsule, Slime layer

  2. Slime layer, Capsule

  3. Mesosome, Capsule

  4. Mesosome, Slime layer

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Correct Option: B
Explanation:

Glycocalyx (mucilage sheath) is the outermost layer of the bacterial cell envelope which consists of non-cellulosic polysaccharides with or without proteins. It may occur in the form of loose sheath, called slime layer. If it is a thick covering, it is called capsule. Glycocalyx gives sticky character to the cell and is not absolutely essential for survival of bacteria. It prevents desiccating, protects from phagocytes, toxic chemicals and viruses and serves in attachment. It may give selective advantage through in certain situations.

So, the correct answer is 'Slime layer, capsule'.