Tag: microbiology: organisms in industry

Questions Related to microbiology: organisms in industry

One of the following is less resistant or more susceptible to antibiotics.

  1. Gram positive bacteria

  2. Gram negative bacteria

  3. Escherichia coli

  4. None of these


Correct Option: A
Explanation:

Gram-negative bacteria have a unique outer membrane. This outer membrane prevents penetration of antibiotics within the cell. However, Gram-positive bacteria do not have an outer LPS membrane. This makes them more susceptible or less resistant to antibiotics than gram-positive bacteria.

Thus, the correct answer is 'Gram-positive bacteria.'

Bacteria which retain purple colour after staining with gram stain is

  1. Gram +ve

  2. Gram -ve

  3. Trichous

  4. Spirillum


Correct Option: A
Explanation:

Gram staining procedure is based on the principle of the ability of microorganisms to retain color of the stains used during the gram staining process. Gram-positive bacteria retain purple color after staining. They are not decolorized by treatment with alcohol. Whereas gram-negative bacteria are decolorized by the alcohol and lose purple color. When again stained with the second stain, they retain pink color. This major difference is due to the difference in the cell wall component of both the bacteria. Gram-negative bacteria contain additional peptidoglycan layer and a thin layer of LPS layer. 

Thus, the correct answer is 'Gram +ve.'

The main difference in Gram $(+)$ve and Gram $(-)$ve bacteria resides in their

  1. Cell wall

  2. Cell membrane

  3. Cytoplasm

  4. Flagella


Correct Option: A
Explanation:

All bacteria posses cell wall. However, the bacteria are classified as Gram positive bacteria and Gram negative bacteria on the basis of their cell wall. Cell wall of Gram positive bacteria consist of multiple layer of peptidoglycan. Cell wall of Gram negative bacteria is made up thin layer of peptidoglycan. In addition, they have one more outer layer of lipopolysaccharide (LPS).

Thus, the correct answer is 'Cell wall.'

Gram $(-)$ bacteria differ from Gram $(+)$ bacteria is having ____________.

  1. Thick wall

  2. Complex wall

  3. Simple wall

  4. Absence of wall lipids


Correct Option: A
Explanation:
Gram positive bacteria differ from Gram negative bacteria in the structure of their cell wall. Gram positive bacteria do not have an outer cell membrane that is present in Gram negative bacteria. The cell wall of Gram positive bacteria have a thick, multi-layered peptidoglycan layer.
 Hence, it retains the crystal violet dye in gram staining. Gram negative bacteria have a thin, single layer of peptidoglycan. Hence, it does not retain the crystal violet dye in gram staining. Gram positive bacteria have techoic acids in the cell wall whereas Gram negative bacteria do not. Gram positive bacteria have low level of lipid content. Gram negative bacteria have high content of lipid, lipopolysaccharide.
Thus, the correct answer is 'Thick wall.'

Gram $(+)$ and Gram $(-)$ forms of bacteria are differentiable through staining with

  1. Saffranin and Gentian Violet

  2. Saffranin and Iodine

  3. Acetocarmine and Iodine

  4. Crystal Violet and Iodine


Correct Option: D
Explanation:

Gram staining procedure is based on the principle of the ability of microorganisms to retain the color of the stains used during the gram staining process. Gram-positive bacteria retain purple color after staining with Crystal Violet stain. Iodine is added as a mordant to form the crystal violet-iodine complex. They are not decolorized by treatment with alcohol. Whereas gram-negative bacteria are decolorized by the alcohol and lose the purple color of Crystal Violet stain. When again stained with second stain Saffranin, they retain pink color. This major difference is due to the difference in the cell wall component of both the bacteria. Gram-negative bacteria contain additional peptidoglycan layer and a thin layer of LPS layer. 

Thus, the correct answer is 'Crystal Violet + Iodine.'

Streptomycin is effective against .......... bacteria

  1. Gram $(+)$

  2. Gram $(-)$

  3. Gram neutral

  4. Both Gram $(+)$ and Gram $(-)$


Correct Option: D
Explanation:

Streptomycin is an antibiotic which is used in the treatment of bacterial infections. It belongs to the Aminoglycoside antibacterial class. It is a broad-spectrum antibiotic. It is effective against both Gram-positive and Gram-negative bacteria. It is used in the treatment of tuberculosis, endocarditis, plague, rat bite fever. 

Thus, the correct answer is 'Both Gram (+) and Gram (−).'

Gram $(-)$ve bacteria possess peptidoglycan and an extra layer of

  1. Protein

  2. Lipoprotein

  3. Lipopolysaccharide

  4. Lipid


Correct Option: C
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 'Lipopolysaccharide.'

The periplasmic space of the Gram$(-)$ bacteria consists of

  1. Lipoprotein

  2. Mucopeptide

  3. Chromoprotein

  4. Glycoprotein


Correct Option: B
Explanation:

Both Gram negative and Gram positive bacteria have a peptidoglycan layer in the cell wall. The peptidoglycan in Gram negative bacteria is present in the periplasmic space. Apart from this, Gram negative bacteria have an outer wall made up of lipopolysaccharide. Peptidoglycan is also called as mucopeptide. It is a polymer that is made up of sugars and amino acids. 

Thus, the correct answer is 'Mucopeptide.'

In the Gram staining procedure, all the bacterial cells get stained with

  1. Mercuric chloride

  2. Crystal violet

  3. Malachite green

  4. Saffranin


Correct Option: B
Explanation:

Gram staining procedure is based on the principle of the ability of microorganisms to retain color of the stains used during the gram staining process. Gram-positive bacteria retain purple color after staining with crystal violet stain. They are not decolorized by treatment with alcohol. Gram-negative bacteria also get stained with crystal violet stain. However, they are decolorized by the alcohol and lose purple color. When again stained with the second stain safranin, they retain pink color. This major difference is due to the difference in the cell wall component of both the bacteria. 

Thus, the correct answer is 'Crystal violet.'

Mucopeptide is abundant in the cell wall of

  1. Cyanobacteria

  2. Gram $(+)$ bacteria

  3. Gram $(-)$ bacteria

  4. Bacteriophage


Correct Option: B
Explanation:

Both Gram negative and Gram positive bacteria have a peptidoglycan layer in the cell wall. It is also called as mucopeptide or murein. However, Gram positive bacteria have thick layer of peptidoglycan. Hence, mucopeptide is abundant in the cell wall of gram positive bacteria. Gram negative bacteria have thin layer of mucopeptide. Apart from this, Gram negative bacteria have outer wall made up of lipopolysaccharide. 

Thus, the correct answer is 'Gram (+) bacteria.'