Tag: microbiology: organisms in industry

Questions Related to microbiology: organisms in industry

A prokaryotic cell lacks 

  1. Cell wall

  2. Cell membrane

  3. Cytoplasm

  4. Nucleolus


Correct Option: D
Explanation:

A prokaryotic cell lacks a nucleolus. A prokaryote is a single-celled organism that lacks a membrane-bound nucleus, mitochondria, or any other membrane-bound organelles. All the intracellular water-soluble components are located together in the same volume enclosed by the cell membrane, rather than in separate cellular compartments.

Difference in Gram +ve  and Gram -ve bacteria is due to

  1. Cell wall

  2. Cell membrane

  3. Ribosome

  4. Cytoplasm


Correct Option: A
Explanation:

The cell wall of certain bacteria shows a characteristic reaction to the stain devised by C. Gram. Those bacteria which retain the stain are known as Gram positive and those which do not retain the stain are called Gram negative.

  • The cell wall in bacteria contains peptidoglycan, a polymer of N-acetyl glucosamine, N-acetyl muramic acid and amino acids.
  • Gram-positive cell walls contain a thick layer of peptidoglycan that encircles the cell.
  • Gram-negative cell walls contain a thin layer of peptidoglycan between the cytoplasmic membrane and the outer membrane.

Bacterial cell wall is composed of peptidoglycan, a complex of oligosaccharides and proteins.        The oligosaccharide component consist of _________

  1. Linear chain of alternating NAG and NAM linked by ${\alpha}$ (1 -4) linkage

  2. Linear chains of alternating NAG and NAM linked by ${\beta}$ (1-4) linkage.

  3. Linear chain of glucose linked by $4{\beta}$ (1-4) linkage.

  4. Linear chain of glucose linked by ${\alpha}$ (1-4) linkage


Correct Option: B
Explanation:

The oligosaccharide component of bacterial cell wall consists of linear chains of alternating NAG and NAM linked by ${\beta}$ (1-4)linkage.

Gram-negative bacteria that cause infections, when stained,  do not retain the crystal violet stain, which tells the researcher that

  1. The peptidoglycan layer is thick and the bacteria are resistant to antibiotics.

  2. The peptidoglycan layer is very thin and the bacteria is susceptible to antibiotics.

  3. The peptidoglycan layer is very thin and the bacteria are resistant to antibiotics.

  4. The peptidoglycan layer contains an impermeable lipid layer.


Correct Option: C
Explanation:

The peptidoglycan layer of the gram negative bacteria are thin and are also referred to as the cell envelope. The layer is wavy and provides resistance to antibiotics. They are more virulent as compared to Gram positive bacteria

So, the correct answer is 'The peptidoglycan layer is very thin and the bacteria are resistant to antibiotics'

Which one of the following is not a characteristic of Gram positive bacteria?

  1. Cell wall is smooth

  2. Mesosomes are distinctively prominent

  3. Basal body of flagellum contains 2 rings

  4. Outer membrane is present


Correct Option: D
Explanation:

Outer membrane and periplasmic space are absent in Gram positive bacteria but present in Gram negative bacteria. The outer membrane in Gram negative bacteria is made up of lipopolysaccharides.

Mucopeptide of cell wall is more in

  1. Gram-positive bacteria

  2. Gram-negative bacteria

  3. Cyanobacteria

  4. Bacteriophage


Correct Option: A
Explanation:

Cell wall of Gram +ve bacteria is made up of peptidoglycans (mucopeptide). Mucopeptide form about 50% of component of cell wall. Cell wall of Gram -ve bacteria is made up of single layer of peptidoglycans.

Cell organelles are the parts of a living cell. All cells have a cell membrane and some cells have a cell wall.
 Which of the following has a cell wall? 
 I. Plants
 II. Bacteria
 III. Fungi

  1. I only

  2. II only

  3. I and II only

  4. II and III only

  5. I, II and III


Correct Option: E
Explanation:
  • Cell wall is the outermost, rigid, protective, non-living and supportive layer found in plant cells, bacteria, fungi, and some protists but absent in animal cells.

1. Plants cell wall is made up of cellulose, hemicellulose, and pectin. Cellulose is a polymer of glucose and pectin is a polymer of galactouronic acid.

2. Bacterial cell wall is made up of protein lipid polysaccharide NAG (N-Acetyl Glucosamine) and NAM (N-Acetyl Muramic Acid).

3. Fungal cell wall is made up of chitin which is a polymer of glucosamine.
Hence all options are correct.

So, the correct answer is 'I, II and III'.

The murein found in bacterial cell is

  1. Derivative of protein

  2. Derivative of fat

  3. Derivative of organic acids

  4. Derivative of sugars


Correct Option: D
Explanation:

The mucopeptide or murein is a polymer of two amino sugars namely N-acetylglucosamine (NAG) and N-acetyl muramic acid (NAM). These NAG and NAM are derivatives of Glucose molecules.

Thus, the correct answer is 'D'.

Exotoxin is produced by

  1. Gram positive bacteria

  2. Gram negative bacteria

  3. Both (a) and (b)

  4. None of the above


Correct Option: A
Explanation:

Exotoxin is produced by mostly gram positive bacteria, these are protenaceous and heat labile compound which are excreted by bacteria out side the cell.

Moving on a grass lawn facilitates better maintenance primarily owing to 

  1. Removal of apical dominance and promotion of lateral meristem

  2. Removal of apical dominance

  3. Wounding which stimulate rapid regeneration

  4. None of the above


Correct Option: B
Explanation:

Sometimes apical bud inhibits the growth of lateral buds, it is called apical dominance. By moving on a grass lawn apical buds are removed and apical dominance of grass is breaked.