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Difficulty: HardKingdom Monera: Bacteria and Cyanobacteria

Match each cellular feature or specialized structure of organisms in Kingdom Monera with its correct biological role or chemical composition.

  • HeterocystSpecialized thick-walled cell dedicated to fixing atmospheric nitrogen in filamentous cyanobacteria.
  • PeptidoglycanCross-linked polymer of amino acids and sugars forming the rigid eubacterial cell wall.
  • MesosomeInvagination of the bacterial plasma membrane associated with cellular respiration and cell division.
  • AkineteThick-walled dormant resting cell that enables cyanobacteria to survive unfavorable conditions.

Answer

Heterocyst matches the specialized nitrogen-fixing cell; Peptidoglycan matches the cross-linked polymer forming the cell wall; Mesosome matches the plasma membrane invagination involved in respiration and division; Akinete matches the dormant resting cell for surviving adverse environments.
Each Moneran cellular structure is correctly paired with its function: Heterocysts fix nitrogen under micro-anaerobic conditions; Peptidoglycan builds the rigid eubacterial cell wall; Mesosomes facilitate respiration and cell division via membrane invagination; and Akinetes function as thick-walled resting cells for surviving adverse environmental conditions.

Step-by-Step Solution

1
Analyze cyanobacterial cell differentiation for nitrogen metabolism
Heterocysts are micro-anaerobic cells specialized for atmospheric nitrogen fixation in cyanobacteria like Nostoc and Anabaena.
The nitrogenase enzyme responsible for nitrogen fixation is sensitive to oxygen, necessitating a specialized thick-walled cell.
2
Examine bacterial cell wall biochemistry
Peptidoglycan is the characteristic polymer network of NAG and NAM chains cross-linked by short peptides in eubacteria.
Distinguishes bacterial cell walls from eukaryotic plant walls composed of cellulose and fungal walls composed of chitin.
3
Identify internal plasma membrane folds in prokaryotes
Mesosomes function analogous to mitochondrial cristae by anchoring respiratory enzymes on folded bacterial cell membranes.
Prokaryotes lack membrane-bound mitochondria, utilizing plasma membrane foldings for ATP synthesis.
4
Identify cyanobacterial perennating structures
Akinetes are resistant, nutrient-rich spores designed for long-term survival.
Allows filamentous cyanobacteria to survive extended periods of drought or extreme cold.

Key Concept

Cellular structures, biochemical composition, and specialized adaptations of prokaryotes in Kingdom Monera.
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Topics

Kingdom Monera: Bacteria and Cyanobacteria

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