🔧 1. Structural Roles of Proteins

🧫 1.1 Proteins in Plasma Membranes

• All living cells are covered by a plasma membrane (a protective skin around the cell).
• Proteins are a major part of this membrane.
• They help the cell control what goes in and out.

🧠 Analogy: Plasma membrane = security gate. Proteins = gatekeepers.

🚪 1.2 Channel Proteins and Material Transport

• Some proteins act as channels or gates in the cell membrane.
• These are called channel proteins.
• They allow specific materials (like ions) to move in and out of the cell.

⚙️ Example: Sodium–Potassium Pump

• Found in nerve cells (neurons)
• Pumps Na⁺ (sodium) out and K⁺ (potassium) in
• Helps in nerve signals and brain function

🧠 Analogy: Like a pump that fills and empties a swimming pool to maintain the right water level.

📌 Why important?
Without this pump, nerves wouldn’t be able to send signals, so you wouldn’t be able to move, feel, or think properly!

🧵 1.3 Fibrous Proteins in Body Structures

Some proteins build your body like bricks build a house.

🧱 Examples:

• Collagen: Found in cartilage (soft bones in joints and nose)
• Keratin: Found in hair, skin, and nails – makes them strong and protective

🧠 Analogy:

• Collagen is like rubber – strong but flexible
• Keratin is like hard plastic – tough and protective

🌟 Summary Table

Basis	Type of Protein	Function	Examples	Analogy
Functional	Structural	Build and support body parts	Collagen, Keratin	Bricks and walls
Functional	Functional	Perform activities	Enzymes, Antibodies	Workers and helpers
Structural	Fibrous	Strong, rope-like, structural	Keratin, Collagen	Threads and ropes
Structural	Globular	Round, active, soluble	Enzymes, Hemoglobin	Soap bubbles or marbles

🧠 Final Mnemonics Recap

1. FiGS – To remember structural types
   • Fibrous = Gives Structure
   • Globular = Soluble and Functional
2. SHiNE – Roles of functional proteins
   • Structure (keratin, collagen)
   • Hormones (insulin)
   • immunity (antibodies)
   • Nerve signals (channel proteins)
   • Enzymes (amylase, lipase)