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Part 1: A terrifying hospital stay (Aaron’s case)

1.

Q: On the surface of skin, Bacteria D feeds off dead skin cells and hairs. What type of symbiotic relationship is this (when not causing an infection)? Why?

A:

→ Commensalism.

Because Bacteria D benefits (it gets food) but the human is not harmed or helped.

It just lives on the skin peacefully.

2.

Q: Bacteria D is found on skin and hair. How would you categorize Aaron’s infection? Opportunistic or exogenous pathogen? Why?

A:

→ Opportunistic pathogen.

Because Bacteria D is normally harmless on healthy skin,

but when Aaron became weak (premature, NICU, catheter), it caused infection.

Opportunistic pathogens cause disease only when the body’s defenses are low.

3.

Q: Bacteria D is a gram-positive bacteria. How are gram-positive and gram-negative bacteria different? What type of antibiotic would you use?

(And sub-questions)

Main Question Answer:

• Gram-positive bacteria have a thick peptidoglycan wall.
• Gram-negative bacteria have a thin peptidoglycan wall plus an extra outer membrane.
• Antibiotic should target: the peptidoglycan cell wall (because humans don’t have cell walls, so it’s a safe target).

Sub-questions:

• What cell structure are we comparing?
  → We are comparing the cell wall (peptidoglycan layer).
• How is this structure different in prokaryotes vs eukaryotes?
  → Prokaryotes (bacteria) have cell walls with peptidoglycan.
  → Eukaryotes (human cells) have no cell wall (only a cell membrane).
• Name and describe 3 differences between bacteria, archaea, and eukaryotes:
  
1. Nucleus:
   
• Bacteria and Archaea = no nucleus (prokaryotes)
• Eukaryotes = have a nucleus
2. 
   
3. Cell Wall Composition:
   
• Bacteria = peptidoglycan
• Archaea = pseudopeptidoglycan or other materials
• Eukaryotes = no peptidoglycan (some like plants have cellulose walls)
4. 
   
5. Size:
   
• Bacteria/Archaea = small (1-10 micrometers)
• Eukaryotes = larger (10-100 micrometers)
6. 
   
• 
  

Would you also like me to help you organize all these answers into a very short paragraph format if you need to turn it in?