Bacterial Morphology and Classification Quiz

Etiology and Pathogenesis

• Etiology is the study of the origin of disease or infection
• Pathogenesis covers the process from the transmission of the infectious agent to the human body, including the incubation period, manifestation of signs and symptoms, the body's reaction, decline of infection, and recovery

Laboratory Diagnosis and Control of Infection

• Laboratory diagnosis is crucial for identifying the cause of an infection
• Specific treatment is essential for controlling the spread of infection

Microbiology and Food Chain

• Microorganisms play a vital role in the food chain as decomposers
• They are essential for the production of edible foods, such as bread (baker's yeast) and wine (fermentation of fruits)

Microbial Taxonomy

• Classification is the process of organizing organisms based on their similarities and differences in terms of morphology, physiology, and genetic traits
• Taxa refer to the grouping of organisms into categories
• The classification hierarchy consists of:
  • Domain level (e.g., Prokaryotes, Eukaryotes, Archaea)
  • Kingdom level (e.g., Animalia, Plantae, Protista, Fungi, Monera)
  • Phylum/Division level
  • Class level
  • Order level
  • Family level
  • Genus level
  • Species level
  • Strain/Variant/Subspecies level

Identification and Characteristics

• Identification is the process of describing the key features of organisms
• Phenotype refers to the observable properties of an organism, such as morphology, staining properties, and serological characteristics
• Genotype refers to the genetic material and composition of nucleic acid of organisms

Bacterial Structure and Function

• Ribosomes are measured in terms of ultracentrifugation
• Morphology of bacteria can be classified into different shapes, such as:
  • Bacillus (rod shape)
  • Coccus (sphere shape)
  • Spirillus (spiral shape)
• Arrangement of bacteria can also be classified, such as:
  • Cocci (singular, in pairs, in a form of 4, 8, chained, or clustered)
  • Bacilli (singular, in pairs, chained, or side by side)

Cell Wall and Internal Parts

• Cell wall separates the internal and external parts of the cell and provides protection, imparts antigenicity, and is responsible for pathogenicity and staining properties
• Internal parts of the cell include:
  • Nucleoid
  • Cytoplasm
  • Ribosomes
  • Cytoplasmic membrane

External Parts and Staining

• External parts of the cell include:
  • Capsule
  • Pili
  • Flagella
• Different types of staining techniques include:
  • Simple staining (1 dye)
  • Differential staining (2 types of dye to differentiate two organisms)
  • Special staining
  • Negative staining

Anatomy of Bacterial Cell Wall

• Gram-positive cell wall is composed of:
  • Thick peptidoglycan (murein)
  • Teichoic acid
  • Lipoteichoic acid
• Gram-negative cell wall is composed of:
  • Thin peptidoglycan
  • Porins
  • Outer membrane with lipoprotein, lipopolysaccharide, and phospholipids
  • Periplasmic space located between the peptidoglycan layer and cytoplasmic membrane