🦠 The Viral Lytic Cycle

About this simulation

A bacteriophage is a virus that infects bacteria. In the lytic cycle it hijacks the host cell's own machinery to mass-produce copies of itself, then destroys the cell to release them. This scene animates the five classic stages of that cycle on a single rod-shaped bacterium, using a tailed phage similar in body plan to the well-studied T4 phage.

The five stages

• Attachment — tail fibers on the phage recognise and bind a specific receptor protein on the bacterial cell wall.
• Penetration (injection) — the tail sheath contracts, driving a hollow tube through the wall and membrane; the phage genome is injected while the empty protein capsid stays outside.
• Biosynthesis — the host's own polymerases and ribosomes are redirected to copy phage DNA and build phage proteins; host DNA is degraded by phage-encoded nucleases.
• Maturation (assembly) — heads, tails and fibers self-assemble into complete progeny virions inside the cell.
• Lysis — a phage-encoded enzyme (lysozyme-like) digests the cell wall from within; the cell swells and bursts, releasing progeny phages to infect new cells.

Controls

• ◀ Prev / Next ▶ — step through the five stages manually.
• Cycle speed — how fast each stage plays out.
• Burst size — how many progeny virions are assembled and released at lysis (real phages typically release 50–200 per cell).
• Auto-advance — toggle continuous looping through the cycle versus manual stepping.
• ↺ Reset cycle — restarts from Attachment. Drag to rotate, scroll to zoom.

Did you know?

The lytic cycle is distinct from the lysogenic cycle, in which some phages instead splice their genome into the host chromosome and lie dormant as a prophage — sometimes for many bacterial generations — before switching to lytic growth.