PetriKey

Concept

Lysogenic vs lytic cycle

Two paths a phage can take

ly-SAH-jeh-nee / LIT-ik

virologyphageprophagetoxingenetics

High-yield clue

In lysogeny the phage integrates as a prophage and can add toxin genes (lysogenic conversion), unlike the lysis-and-burst lytic cycle.

Overview

The two replication strategies of a bacteriophage: the lytic cycle rapidly makes new virions and bursts the cell, while lysogeny integrates the phage genome as a quiet prophage that can later be induced. Lysogeny can add new toxin genes to the host.

Classification

  • Phage life-cycle concept
  • Lytic: replicate and burst
  • Lysogenic: integrate as prophage
  • Inducible switch between states

Lab & identification clues

  • Prophage integration vocabulary
  • Temperate phage concept
  • Lysogenic-conversion toxin-gene vocabulary

Associations

  • Diphtheria toxin gene from a prophage
  • Cholera and Shiga toxin phage-encoding vocabulary
  • Prophage induction under stress

Commonly confused with

  • Generalized transduction
  • Latent animal-virus infection

Your notes

Original microbiology concept summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC/WHO topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment selection, infection-control instructions, or specimen-handling guidance.

OpenStax: Microbiology 2e concept foundationssourceNCBI Bookshelf: Medical Microbiology general conceptssourceCDC: CDC public-health concept pagessource