Bacterial Morphology

Microbe Classification

Bacterial Morphology

• Cell Shape and Arrangement
  • Cocci (spherical): can be in clusters (staphylococci), chains (streptococci), or pairs (diplococci)
  • Bacilli (rod-shaped): can be single or in chains
  • Spiral-shaped (spirilla) or comma-shaped (vibrios)
• Cell Size and Motility
  • Typically 0.5-5.0 μm in length
  • Can be motile (flagella) or non-motile
• Cell Wall Composition
  • Peptidoglycan (peptide-sugar molecule) provides structural support
  • Gram-positive bacteria have thick peptidoglycan layer, Gram-negative have thin layer with outer membrane
• Staining Characteristics
  • Gram staining: distinguishes between Gram-positive and Gram-negative bacteria
  • Acid-fast staining: detects mycobacteria

Fungal Classification

• Kingdom Fungi
  • Subkingdoms: Chytridiomycota, Zygomycota, Ascomycota, and Basidiomycota
• Characteristics
  • Eukaryotic, heterotrophic organisms
  • Cell walls composed of chitin
  • Obtain nutrients by decomposing organic matter or forming symbiotic relationships
• Classification based on Reproductive Structures
  • Zygomycota: produce zygospores
  • Ascomycota: produce asci containing ascospores
  • Basidiomycota: produce basidia containing basidiospores
• Examples of Fungi
  • Mushrooms (Basidiomycota)
  • Molds (Ascomycota)
  • Bread mold (Zygomycota)

Bacterial Morphology

• Bacteria can be classified based on cell shape, with three main types: cocci (spherical), bacilli (rod-shaped), and spiral-shaped (spirilla) or comma-shaped (vibrios)
• Cocci can be arranged in clusters (staphylococci), chains (streptococci), or pairs (diplococci)
• Bacilli can be single or in chains

Cell Size and Motility

• Bacteria typically range in length from 0.5-5.0 μm
• Some bacteria are motile, using flagella for movement, while others are non-motile

Cell Wall Composition

• Peptidoglycan, a peptide-sugar molecule, provides structural support to bacterial cells
• Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin layer with an outer membrane

Staining Characteristics

• Gram staining is used to distinguish between Gram-positive and Gram-negative bacteria
• Acid-fast staining is used to detect mycobacteria

Fungal Classification

• The kingdom Fungi is divided into four subkingdoms: Chytridiomycota, Zygomycota, Ascomycota, and Basidiomycota

Characteristics of Fungi

• Fungi are eukaryotic, heterotrophic organisms
• Their cell walls are composed of chitin
• They obtain nutrients by decomposing organic matter or forming symbiotic relationships

Classification based on Reproductive Structures

• Zygomycota fungi produce zygospores
• Ascomycota fungi produce asci containing ascospores
• Basidiomycota fungi produce basidia containing basidiospores

Examples of Fungi

• Mushrooms belong to the Basidiomycota subkingdom
• Molds belong to the Ascomycota subkingdom
• Bread mold belongs to the Zygomycota subkingdom