🔶 SHAPES OF VIRUSES

Viruses come in various shapes, just like toys or gadgets. Here are the main ones:

🧫 In Animal & Plant Viruses:

• Polyhedral (many-sided)
• Helical (spiral-shaped)

🦠 In Bacteriophages (Viruses that infect bacteria):

• Cubical
• Icosahedral (20-faced)
• Helical
• Complex (looks like a spider or robot: a head + a tail)

🎨 Imagine them like LEGO shapes – some are balls, some are rods, some are spider-like robots!

🧬 BACTERIOPHAGES — VIRUSES THAT ATTACK BACTERIA

What are Bacteriophages?

• Also called phages.
• These are viruses that infect bacteria.
• Discovered as early models of virus structure.
• One famous type is the T-phage that infects E. coli bacteria.

⚙️ STRUCTURE OF T4 BACTERIOPHAGE

Let’s break it into parts:

🔺 Head

• Shape: A hexagonal (six-sided) prism or pyramid.
• Material: Made of proteins.
• Inside: Long double-stranded DNA.

🧪 Tail

• Straight, rod-like part connected to the head.
• Has:
  • Inner core (protein)
  • Outer sheath (protein)
• Neck connects tail and head.
• End plate at the end of the tail.

🕷️ Tail Fibres

• Six thin fibres attached to the end plate.
• Function: Help the virus attach to the bacterial wall.
• Made of proteins.

💡 Mnemonic to Remember Parts:
“Happy Tiny Insects Never Eat Tiny Food”

• H = Head
• T = Tail
• I = Inner core
• N = Neck
• E = End plate
• T = Tail fibres
• F = Function (attach to bacteria)