BIO2104 Weekly Review for Weeks 9 and 10

Domains of Life

• Domain Bacteria

  • Characteristics: Simple, single-celled (prokaryotes)
  • Habitat: Ubiquitous (soil, water, human body)
  • Examples: E. coli, S. aureus

• Domain Archaea

  • Characteristics: Single-celled, unique cell structures, extreme survival
  • Habitat: Extreme environments (hot springs, salty lakes)
  • Examples: Methanobacterium, Halobacterium

• Domain Eukarya

  • Characteristics: Complex cells with nucleus (eukaryotes), single or multi-celled
  • Habitat: Ubiquitous (land, water, air)
  • Examples: Humans, S. cerevisiae (yeast)

Kingdoms

• Kingdom Eubacteria: Prokaryotic, found everywhere, includes harmful and beneficial strains.
• Kingdom Archaebacteria: Prokaryotic, lives in extreme environments, unique metabolism.
• Protista: Mostly single-celled eukaryotic organisms; some move with cilia or flagella.
• Fungi: Mainly multicellular, absorb nutrients from decomposing matter; cell walls made of chitin.
• Plantae: Multicellular, photosynthetic; cell walls made of cellulose.
• Animalia: Multicellular, consumers; no cell walls, complex organ systems.

Characteristics Differentiating Domains

• Archaea vs. Bacteria and Eukarya:
  • Prokaryotic structure differentiated by 16S rRNA sequencing
  • Cell walls made of proteins or pseudomurein
  • Unique RNA polymerase similar to eukaryotes

Viral Species Characteristics

• Not living cells, need a host for reproduction.
• Genetic material: DNA or RNA (not both).
• Have capsid (protein coat); host specificity.

Groups of Archaea

• Extreme Thermophiles: Thrive in hot environments (e.g., Sulfolobus).
• Extreme Halophiles: Adapted to highly salty environments (e.g., Halobacterium).
• Methanogens: Produce methane, found in anaerobic environments (e.g., Methanobacterium).

Example Bacterial Diseases

1. Rickettsia rickettsii

   • Disease: Rocky Mountain spotted fever
   • Gram reaction: Gram-negative
   • Key characteristics: No toxins; transmission via ticks.
   • Symptoms: High fever, headache, rash.

2. Bordetella pertussis

   • Disease: Whooping cough
   • Gram reaction: Gram-negative
   • Toxin: Pertussis toxin (A-B type).
   • Symptoms: Paroxysmal cough, can be fatal.

3. Neisseria meningitidis

   • Disease: Meningococcal disease
   • Gram reaction: Gram-negative
   • Key characteristics: No toxin; droplet transmission.
   • Symptoms: Severe headache, nausea, can be lethal.

4. Vibrio cholerae

   • Disease: Cholera
   • Gram reaction: Gram-negative
   • Toxin: Cholera toxin (A-B type).
   • Symptoms: Severe diarrhea, dehydration.

5. Yersinia pestis

   • Disease: Plague
   • Gram reaction: Gram-negative
   • Transmission via flea bites or droplets.
   • Symptoms: Fever, weakness, coughing.

6. Salmonella enterica, serotype Typhi

   • Disease: Enteric fever
   • Gram reaction: Gram-negative
   • Toxin: Endotoxin.
   • Symptoms: Gastrointestinal pain, fever.

7. Syphilis

   • Gram reaction: Gram-negative
   • Transmission: Direct contact; causes painless sores.
   • Symptoms: Rash, flu-like syndrome, late-stage complications.

8. Chlamydia

   • Gram reaction: Gram-negative
   • Transmission: Droplet, vertical, and direct contact.
   • Symptoms: Often asymptomatic, pain in urination.

9. Clostridium tetani

   • Disease: Tetanus
   • Gram reaction: Gram-positive
   • Toxin: Tetanus toxin; leads to muscle spasms.
   • Route of transmission: Skin injuries.

10. Corynebacterium diphtheriae

    • Disease: Diphtheria
    • Gram reaction: Gram-positive
    • Toxin: Diphtheria toxin; leads to airway blockage.
    • Symptoms: Difficulty swallowing, fever, throat pseudomembrane.

11. Mycobacterium tuberculosis

    • Disease: Tuberculosis
    • Gram reaction: Weakly gram-positive
    • Transmission: Airborne droplets.
    • Symptoms: Persistent cough, chest pain, night sweats.