Examkin

Question

Difficulty: MediumKingdom Monera: Bacteria and Cyanobacteria

During a microbiological investigation of a soil sample, a technician treats a bacterial culture with an antibiotic that selectively inhibits the cross-linking of murein during cell wall synthesis. Which cellular structure is directly affected by this treatment?

  1. A
    Cellulose wall
  2. B
    Protein capsid
  3. Peptidoglycan layerAnswer
  4. D
    Chitinous envelope

Answer

Peptidoglycan layer
The correct answer identifies the peptidoglycan layer. Murein is the alternative chemical name for peptidoglycan, which forms the tough outer cell wall characteristic of bacteria (Kingdom Monera). Antibiotics like penicillin specifically interfere with peptidoglycan synthesis, weakening the wall.

Step-by-Step Solution

1
Identify the biological Kingdom and group of organisms referenced in the prompt.
The organism is a bacterium, belonging to Kingdom Monera.
Bacteria are prokaryotic unicellular organisms in Kingdom Monera.
2
Determine the biochemical composition of the bacterial cell wall.
Bacterial cell walls are composed of peptidoglycan (murein).
Peptidoglycan consists of repeating disaccharides (NN-acetylglucosamine and NN-acetylmuramic acid) cross-linked by amino acid chains.
3
Relate the mode of action of the murein-inhibiting antibiotic to the targeted structure.
Disrupting murein synthesis weakens the peptidoglycan layer, leading to osmotic lysis.
Murein is synonymous with peptidoglycan in bacterial cell envelope biochemistry.

Key Concept

Bacterial cell wall composition (Peptidoglycan/Murein)
Estimated Time:1m 0s
Rate this question

Topics

Kingdom Monera: Bacteria and Cyanobacteria

More questions from this topic