A2.3.4 (HL)—Lysogenic cycle
During lysogeny, lambda phage DNA integrates into the bacterial chromosome as a dormant prophage, replicates with its host, and may later enter lysis.
- Syllabus
- First assessment 2025
- Objective
- A2.3.4
- Level
- HL
Exam analysis
Chance of appearing1%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper2
Typical marks3
Common command terms
- Explain
Recent exam appearances
May 2025Paper2 ["HL"] · TZ14(c)[ 3 ]A2.3.4 (HL)—Lysogenic cycle
Practice this objective
Coverage 2025–2025 · Updated 15 Jul 2026
Concept essentials
- Lambda DNA integrates into the bacterial chromosome during lysogeny.
- Integrated lambda DNA is called a prophage.
- The prophage is copied with host DNA and inherited by daughter cells.
- The lysogenic state delays virion assembly and host-cell lysis.
- Induction can excise the prophage and initiate the lytic cycle.