🧬 Types of Cells

There are two basic types of cells:

• Prokaryotic (simple)
• Eukaryotic (complex)

1. Prokaryotic Cells

• Found in bacteria.
• They don’t have a nucleus or membrane-bound organelles.
• All cellular activities happen in the cytoplasm.

🧠 Mnemonic to Remember:
“Pro = No”

Prokaryotes have No nucleus.

📌 Example: Bacteria like E. coli.

2. Eukaryotic Cells

• Found in plants, animals, fungi, and protists (like Euglena).
• Have a nucleus and membrane-bound organelles.
• Can be unicellular (e.g., yeast, Euglena) or multicellular (e.g., humans, trees).

🧠 Mnemonic to Remember:
“Eu = True”

Eukaryotes have a True nucleus.

🧱 The Cell Wall

Definition: A more or less solid outer covering that gives the cell shape, protection, and support.

📌 Present In:

• Plants, algae, fungi, and bacteria.
• Absent in animals.

🧠 Real-life Example: Think of a building. The outer walls are like the cell wall—they protect everything inside and maintain the structure.

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🧪 What is a Protoplast?

When the cell wall is removed using special enzymes, what remains (nucleus, cytoplasm, cell membrane) is called a protoplast.

🧠 Think of peeling a fruit. After removing the outer skin (cell wall), the soft inner part (protoplast) remains.

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🧩 Components of the Cell Wall

1. Primary Cell Wall

• First wall formed.
• Made of polysaccharides:
  • Cellulose (main fiber),
  • Hemicellulose, and
  • Pectin (gel-like material).

💡 These substances form a mesh-like structure. They’re held together with hydrogen bonds like threads in a net.

📌 Proteins also exist in the wall, helping in flexibility and growth.

2. Middle Lamella

• Sticky layer between two plant cells.
• First to form during cell division (cytokinesis).
• Made of calcium and magnesium pectates—sticky salts of pectic acid.

🧠 Real-life Example: Think of jam or jelly—it’s sticky and holds things together. That’s what middle lamella does between cells.

🧠 Mnemonic:
“Middle = Jelly = Join”

Middle lamella acts like jelly to join cells together.