Morphology & Structure of Bacteria

• Bacterial Morphology studies:

  • Bacterial Shape
  • Bacterial Size
  • Bacterial Cell Arrangement
  • Gram Staining
• What are the bacterial shapes called?

  • Round (Cocci)
  • Rod-shaped (rods)
  • Spiral (spirilli)
• What are examples of Round (cocci) Bacteria?

  • Staphylocci
  • Streptcocci
  • Diplococci: (pneumococci , meningococci)
• What are examples of Rod-shaped (rods) Bacteria?

  • non-spore forming: M.tuberculosis, C. diphtherine
  • spore-forming (bacilli): (clostridia, B.anthracis)
• What are examples of Spiral (spirilli) Bacteria?

  • Vibrios: (V.cholerae) - 1 Curve
  • Spirilli:(Helibacter) - 2 Curves
  • Spirochaetes: Treponema, Leprospira, Borrelia - Many Curves
• Types of Cocci

  
• Types of Bacterial Cell Arrangement?

  • Single: monococci
  • Pairs: diplococci
  • Tetrads: sarcina
  • Chains: streptococci, B. anthracis
  • Clusters: staphylococci
• What are the types of Bacterial Sizes?

  1. Small: (0.2 - 0.3 micrometers)
  2. Medium: (0.5-2 micrometers)
  3. Large: (3-10 micrometers)
• What are the examples of Small bacteria?

  • Haemophillus
  • Brucella
• What are the examples of Medium bacteria?

  • Staphylococci
  • Streptococci
  • E.coli
• What are the examples of Large bacteria?

  • Clostridia
  • B. anthracis
• What does the Bacterial Cell envelope contain/ consist of?

  • Cell wall (CW)
  • Cytoplamic Membrane (CM)
• What does the Cell wall consist of?

  Peptidoglycan

  1. Glycan part: N-acteyl glucosamine, N-acetyl muranic acid & Beta-1,4 gkycosidic link
  2. Peptide part
• What are the examples of Acid-fast Cell walls?

  • Genus Mycobacterium
  • Nocardia
• What are the methods of studying bacterial structures?

  Microscopic

  1. Native
  2. Staining: Simple & Complex
• What are the examples of simple staining?

  • Loffler
  • Pfeiffer
• What are the examples of complex staining?

  • Gram
  • Neisser
  • Zhiel-Neelsen
• How many spores does a bacterium have?

  • Central Spore
  • Terminal Spore
• Spore formation is performed in lack of nutrients in the medium
• What are the types of bacterial spores?

  • According to location in the cell
  • According to shape
  • According to their capacity to deform the cell
• What are the examples of types of bacterial spores according to location in the cell?

  • Central: B.anthracis
  • Terminal: C. tetani
  • Subterminal: C. perfingens
• What are the examples of types of bacterial spores according to shape?

  • Round
  • Oval
• What are the examples of types of bacterial spores according to their capacity to deform the cell?

  • deforming: Clostridium
  • non-deforming: B. anthracis
• What are the types of Pilli (fimbriae)

  • Common (adhesins)
  • Sex (participate in conjugation)
• What are the functions of Pilli (fimbriae)

  • Adhesion to cells (gonococci , E.coli)
  • participation in conjugative transfer
  • Ag properties (F Ag)
• What are the different types of Flagella?

  • One-polar flagella (lophotrichous)
  • whole surface (peritrichous)
  • bipolar flagella (amphitrichous)
  • single flagella (monotrichous)
• What are the examples of monotrichous flagella?

  • Vibrio Cholerae
• What are the examples of lophotrichous flagella?

  • Bartonella Bacilliformis
• What are the examples of amphitrichous flagella?

  • Spirillum Serpens
• What are the examples of peritrichous flagella?

  • Escherichia coli
• What are the functions of flagella?

  • motion
  • virulence factor
  • antigenic
  • receptor
• What is the structure of flagella?

  It has 3 parts:

  • filament: long, thin, helical structure composed of protein (flagellin)
  • hook: curved sheath
  • basal body: stack of rings firmly anchored in cell wall
• What are the non-essential structures of Bacteria?

  • Capsule
  • Flagella
  • Pilli
  • Spores