🧬 Lesson 9

– Classification of Proteins

🧠 What Are Proteins?

Proteins are very important building blocks of life. They are large, complex molecules made from amino acids, just like a house is built using bricks.

Proteins are found everywhere in your body – in your muscles, skin, hair, blood, enzymes, hormones, and even in your nails. They help the body grow, repair, and carry out important jobs (like digestion and transport of materials).

📌 In simple words:
Proteins = Body’s workers + Body’s building material.

📚 Classification of Proteins – How to Group Them

Proteins are very diverse, meaning there are many types doing many different jobs. So, scientists decided to classify (group) them based on different features.

🧭 Basis of Classification

Proteins can be classified in two ways:

✅ 1. Functional Basis – What They Do

This classification is based on what the protein does or its role in the body.

There are two types:

🔸 Structural Proteins

• These proteins provide support and shape to body parts.
• Think of them as the bricks and walls of your body.
• 🧱 Examples:
  • Collagen – found in cartilage, gives strength and flexibility.
  • Keratin – found in hair, nails, and skin, gives hardness and protection.

🔸 Functional Proteins

• These proteins do the work inside your body.
• Think of them as the electricians, cleaners, and helpers of your body.
• 🛠️ Examples:
  • Enzymes – speed up chemical reactions (like digestion).
  • Antibodies – help fight germs.
  • Hormones – send messages (like insulin controls sugar).

✅ 2. Structural Basis – What They Look Like

🔬 Scientists mostly use this method today because it’s based on the shape or structure of the protein.

There are two main types:

🔹 Fibrous Proteins

• Long, rope-like, and strong
• Insoluble in water (do not dissolve)
• Used to build body structures

🧵 Examples:

• Collagen – in tendons and cartilage
• Keratin – in hair and nails

🧠 Analogy: Fibrous proteins are like threads or ropes used in construction.

🔸 Globular Proteins

• Round, compact, and soluble in water
• Usually involved in metabolic functions (like transport, reactions, defense)

💧 Examples:

• Hemoglobin – carries oxygen in blood
• Enzymes – like amylase, help digest food

🧠 Analogy: Globular proteins are like soap bubbles – small, round, and active.

🧠 Mnemonic to Remember:

To remember Fibrous vs. Globular, use:

🔤 “FiGS”
Fibrous = Gives Structure
Globular = Soluble and Functional

🧪 Roles of Proteins in Life

Now let’s see what amazing jobs proteins do inside living things: