Prokaryotic Cells: Tiny but Mighty! 🦠

⭐ Meet the Prokaryotes

These simple cells are found in:

  • Bacteria
  • Blue-green algae
  • Mycoplasma
  • PPLO (Pleuro Pneumonia Like Organisms)

They’re smaller than eukaryotic cells and multiply super fast! 🚀

🔍 Basic Features

  • No well-defined nucleus (DNA floats freely!)
  • Always have a cell wall (except Mycoplasma)
  • Genetic material is “naked” (not covered by nuclear membrane)
  • Only organelle present: ribosomes

🧬 Genetic Material

  • Main DNA: Single circular chromosome
  • Plasmids: Extra small circular DNA that give special powers like antibiotic resistance! 💊

🧱 Cell Envelope (3 Layers)

  1. Glycocalyx (outermost):
    • Loose = Slime layer
    • Thick/Tough = Capsule
  2. Cell Wall: Gives shape & prevents bursting
  3. Plasma Membrane: Selectively permeable gatekeeper 🚪

🔬 Gram Staining (Super Important!)

  • Gram-positive: Stain taken → Purple!
  • Gram-negative: Stain not taken → Pink!

🌀 Mesosome – The Prokaryote Superstar!

Folded parts of the plasma membrane that help with:

  • Cell wall formation 🧱
  • DNA replication 🧬
  • Respiration 💨
  • Increasing surface area 📏

Looks like: Vesicles, Tubules, Lamellae

🏃 Motility & Attachment

  • Flagella (for movement):
    • Made of: Filament + Hook + Basal body
    • Number/arrangement varies
  • Pili: Long tubes for attachment
  • Fimbriae: Bristle-like fibers to stick to surfaces

🧪 Ribosomes & Inclusion Bodies

  • Ribosomes:
    • Size: 70S (50S + 30S subunits)
    • Job: Make proteins �
    • Form polysome chains on mRNA
  • Inclusion Bodies (Storage Units):
    • Store stuff like phosphate, glycogen
    • No membrane! (e.g., gas vacuoles in bacteria)

📏 Size Comparison

  • Typical bacteria: 1-2 μm
  • PPLO: ~0.1 μm
  • Viruses: 0.02-0.2 μm

💡 NEET Must-Knows

  1. Gram staining (Positive vs. Negative bacteria)
  2. Plasmids: Their role in antibiotic resistance & genetic engineering
  3. Mesosome functions (respiration, DNA distribution)
  4. Ribosome size: 70S with 50S+30S subunits
  5. Flagella structure: Filament, hook, basal body

✨ Fun Fact

Some bacteria have chromatophores (membranes with pigments) for photosynthesis! 🌈