Final- notes

  

🔬 Step 1: Draw the 4 Cells

1. Prokaryotic Cell (Bacterium)
   Label:
   
• Cell wall (peptidoglycan)
• Plasma membrane
• Cytoplasm
• DNA (circular, no nucleus)
• Ribosomes (small)
• Flagella or pili (optional)
2. 
   
3. Eukaryotic Cell 1: Human Skin Cell
   Label:
   
• Nucleus (with DNA inside)
• Plasma membrane (no cell wall)
• Cytoplasm
• Mitochondria
• Ribosomes
• Endoplasmic reticulum
• Golgi apparatus
4. 
   
5. Eukaryotic Cell 2: Plant Cell
   Label:
   
• Nucleus
• Cell wall (cellulose)
• Plasma membrane
• Chloroplasts
• Large central vacuole
• Mitochondria
• Ribosomes
6. 
   
7. Eukaryotic Cell 3: Yeast Cell (Baker’s Yeast)
   Label:
   
• Nucleus
• Cell wall (made of chitin)
• Plasma membrane
• Mitochondria
• Vacuole
• Ribosomes
8. 
   

🔍 Step 2: Highlight Key Differences

Between Bacteria (Prokaryote) and Eukaryotic Cells:

4. RNA viruses use an enzyme called RNA-dependent RNA polymerase (RdRp) to copy their genes.

🦠 Microbiology Summary: Pathogens, Immunity & Microbial Relationships

🔬 1. Types of Microbial Relationships

• Mutualism: Both the human and the microbe benefit.
  → Example: Gut bacteria make vitamins.

• Commensalism: Microbe benefits, human is not affected.
  → Example: Skin bacteria.

• Parasitism: Microbe benefits, human is harmed.
  → Example: Tapeworm or malaria parasite.

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🧫 2. Types of Pathogens

• Opportunistic pathogens: Already in the body (normal microbiota) but can cause disease when:

  • They enter the wrong place (e.g., bloodstream).

  • The immune system is weak.

  • Antibiotics disturb the balance.

• Exogenous pathogens: Come from outside the body and enter through:

  • Air (inhalation)

  • Food or water

  • Cuts or wounds

  • Insect bites

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🛡️ 3. Types of Immunity

• Natural active immunity: You get sick, and your body makes memory cells (long-lasting protection).

• Artificial active immunity: You get a vaccine, and your body makes memory cells.

• Natural passive immunity: Antibodies passed from mother to baby (short-term protection).

• Artificial passive immunity: You receive ready-made antibodies from a shot (e.g., rabies antibody injection).

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🧬 4. Immune System Defenses

• NK cells (natural killer): Destroy infected or abnormal cells.

• Plasma cells: Make antibodies.

• Macrophages: Eat invaders (phagocytosis).

• Helper T cells: Help start the immune response.

• Antibodies: Proteins that bind to pathogens and mark them for destruction.

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💊 5. Disrupting Normal Microbiota

• Antibiotics can kill good bacteria.

• This can lead to overgrowth of harmful ones like Clostridium difficile (C. diff).

• This causes infections, especially in the intestines.

Virus is not living cell; they hide in the host cell. It is hard to target because hidden in the host cell could hurt the host cell. 

Type	Cell or Not?	Living?	Example
Bacteria	✅ Unicellular (1 cell)	✅ Living	E. coli, Staph
Archaea	✅ Unicellular (1 cell)	✅ Living	Extremophiles
Protists	✅ Unicellular (usually)	✅ Living	Amoeba, Paramecium
Viruses	❌ Not a cell at all	❌ Not truly living	Flu virus, COVID-19

 viruses so hard to treat?

• Viruses are not living cells — they hide inside our own cells.

• They use our own machinery to copy themselves → hard to target without hurting our own cells.

• Antibiotics don’t work against viruses.

• Only specific antivirals or vaccines can help.

3. How to identify different types of microbes under the microscope

• Bacteria: Tiny, usually seen with oil immersion lens (1000x); shape (round, rod, spiral); Gram stain helps

• Fungi: Larger, can see yeast buds or mold hyphae at 400x

• Parasites: Usually bigger, can see whole structures (like worm eggs)

• Viruses: Too small for light microscope — need electron microscope or detect with molecular tests (PCR)

Microbe	Features	How to Identify
Bacteria	Prokaryotic cells, cell wall, single-celled	Shape (cocci, bacilli, spirilla), Gram stain, culture
Fungi	Eukaryotic, have nuclei, can be yeast or mold	Seen under light microscope; culture shows fuzzy or budding
Viruses	Not living, DNA or RNA in protein shell	Need electron microscope or PCR; can’t grow on plates, only in living cells