MICROPARA3

• What is the distinction between acellular and cellular entities in microbiology?

  Acellular entities lack cellular structure.
• What are the characteristics of acellular entities?

  • Lack cellular machinery (no ribosomes, organelles)
  • Require a host for replication
  • Capable of causing diseases
• What are the characteristics of cellular entities?

  • Have a cellular structure with cytoplasm
  • Capable of independent metabolism and reproduction
  • Can form complex multicellular structures
• What are viruses classified as?

  They are acellular entities.
• What is the size range of viral particles?

  10 to 300 nm in diameter.
• What are the components of a virus?

  DNA or RNA enclosed in a capsid.
• What are capsomeres?

  Small protein units that make up capsids.
• What is the nucleocapsid?

  The combination of nucleic acid and capsid.
• What types of cells can viruses infect?

  Almost any cell, including bacteria.
• What is "tropism" in viruses?

  Restriction to specific cell types in hosts.
• How do viruses reproduce?

  Only when they infect a host cell.
• What are the five specific properties of viruses?

  1. One nucleic acid (DNA or RNA)
  2. Multiply only inside host cells
  3. Do not divide by binary fission
  4. Lack genes for energy production
  5. Depend on host for protein production
• What disease does the Dengue Virus cause?

  Dengue fever.
• What disease is caused by Varicella-Zoster Virus?

  Chickenpox.
• What disease does SARS-CoV-2 cause?

  Coronavirus disease (COVID-19).
• What disease is caused by Coxsackie A Virus?

  Hand-Foot-Mouth Disease.
• What are the three major theories regarding the origin of viruses?

  1. Coevolution Theory
  2. Retrograde Evolution Theory
  3. Escaped Gene Theory
• How do viruses replicate?

  Only in living cells using host machinery.
• What is the duration of the virus replication cycle?

  6-8 hours to over 40 hours.
• What are the steps of viral replication?

  1. Attachment (Adsorption)
  2. Penetration
  3. Uncoating
  4. Biosynthesis
  5. Assembly
  6. Release
• What are viroids?

  Small, circular RNA molecules without proteins.
• What is the pathogenic effect of viroids?

  Pathogenic to humans, mostly in plants.
• What are prions?

  Infectious proteins causing spongiform encephalopathies.
• What disease is caused by prions?

  Kuru, a rare disease from contaminated tissue.
• What is the average size of a coccus?

  About 1 µm in diameter.
• What is the purpose of gram staining?

  Differentiates gram-positive from gram-negative bacteria.
• What are the reagents used in gram staining?

  • Primary stain: Crystal Violet
  • Mordant: Gram's iodine
  • Decolorizer: Ethyl alcohol or acetone
  • Counterstain: Safranin O or Carbolfuchsin
• What does the primary stain do in gram staining?

  Stains all bacteria blue to purple.
• What is the function of the mordant in gram staining?

  Enhances reaction between cell wall and primary stain.
• What happens during the decolorization step in gram staining?

  Gram-positive bacteria retain the primary stain.
• What is the result of the counterstain in gram staining?

  Stains gram-negative bacteria pink to red.
• What is the acid-fast stain used for?

  • Differentiates acid-fast organisms from non-acid-fast organisms.
  • Acid-fast organisms stain red.
• What is the primary stain in the Ziehl-Neelsen method?

  Carbolfuchsin.
• What is the difference in the mordant between Ziehl-Neelsen and Kinyoun methods?

  Ziehl-Neelsen uses heat; Kinyoun uses phenol.
• What are the three shapes of bacteria?

  Cocci, bacilli, and spirilla.
• What is the average size of a bacillus?

  1 µm wide by 3 µm long.
• What are the arrangements of cocci bacteria?

  • Singly
  • Pairs (diplococci)
  • Chains (streptococci)
  • Clusters (staphylococci)
  • Groups of four (tetrad)
  • Groups of eight (octad)
• What are the characteristics of bacilli?

  • Rod-shaped organisms
  • Can be long or short, thin or thick
  • Some resemble coccobacilli
• What are the types of motility in bacteria?

  • Motile: can swim
  • Nonmotile: cannot swim
• What are the types of flagella in bacteria?

  • Monotrichous: single polar flagellum
  • Lophotrichous: tuft at one end
  • Amphitrichous: flagella at both ends
  • Peritrichous: flagella all around