Write a short summary that contrasts how recombination occurs in bacteria and bacteriophages.
Table of contents
- 1. Introduction to Genetics51m
- 2. Mendel's Laws of Inheritance3h 37m
- 3. Extensions to Mendelian Inheritance2h 41m
- 4. Genetic Mapping and Linkage2h 28m
- 5. Genetics of Bacteria and Viruses1h 21m
- 6. Chromosomal Variation1h 48m
- 7. DNA and Chromosome Structure56m
- 8. DNA Replication1h 10m
- 9. Mitosis and Meiosis1h 34m
- 10. Transcription1h 0m
- 11. Translation58m
- 12. Gene Regulation in Prokaryotes1h 19m
- 13. Gene Regulation in Eukaryotes44m
- 14. Genetic Control of Development44m
- 15. Genomes and Genomics1h 50m
- 16. Transposable Elements47m
- 17. Mutation, Repair, and Recombination1h 6m
- 18. Molecular Genetic Tools19m
- 19. Cancer Genetics29m
- 20. Quantitative Genetics1h 26m
- 21. Population Genetics50m
- 22. Evolutionary Genetics29m
5. Genetics of Bacteria and Viruses
Bacteriophage Genetics
Problem 12
Textbook Question
Define plaque, lysogeny, and prophage.

1
Plaque: A plaque is a clear area on a bacterial lawn (a uniform layer of bacteria grown on an agar plate) where bacteriophages (viruses that infect bacteria) have lysed the bacterial cells. Each plaque represents the site where a single virus particle infected a bacterial cell and initiated a cycle of infection and lysis, spreading to neighboring cells.
Lysogeny: Lysogeny is a process in which a bacteriophage integrates its genetic material into the host bacterium's genome instead of immediately initiating the lytic cycle. The viral DNA, now called a prophage, remains dormant and replicates along with the host cell's DNA during cell division, without causing harm to the host.
Prophage: A prophage is the viral DNA that has been integrated into the bacterial genome during lysogeny. It remains inactive and is replicated as part of the host's DNA until certain conditions (e.g., stress or UV light) trigger its activation, leading to the lytic cycle and the production of new virus particles.
Understand the relationship: Plaques are the result of the lytic cycle, where bacteriophages actively destroy bacterial cells. In contrast, lysogeny involves the integration of the prophage into the host genome, which does not immediately kill the host cell.
Recognize the importance: These terms are fundamental in understanding bacteriophage life cycles and their interactions with bacterial hosts, which have applications in molecular biology, genetics, and biotechnology.

This video solution was recommended by our tutors as helpful for the problem above
Video duration:
1mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Plaque
In microbiology, a plaque refers to a clear zone that appears on a bacterial lawn due to the lysis of bacteria by bacteriophages. When a bacteriophage infects a bacterium, it replicates and eventually causes the bacterium to burst, releasing new phages that can infect neighboring cells. This results in a visible area devoid of bacteria, which can be counted to determine the concentration of phages in a sample.
Recommended video:
Guided course
Plaques and Experiments
Lysogeny
Lysogeny is a viral replication cycle in which a bacteriophage integrates its genetic material into the host bacterium's genome, forming a stable relationship. In this state, the viral DNA, known as a prophage, is replicated along with the host's DNA during cell division without causing immediate harm to the host. This can provide the bacterium with new traits, such as immunity to superinfection by other phages.
Recommended video:
Guided course
Decision Between Lytic and Lysogenic Cycles
Prophage
A prophage is the form of a bacteriophage's genetic material when it is integrated into the host bacterium's chromosome during lysogeny. This dormant state allows the viral DNA to be replicated alongside the host's DNA without causing cell lysis. Under certain conditions, such as stress or damage to the host, the prophage can be excised from the genome and enter the lytic cycle, leading to the production of new phage particles.
Recommended video:
Guided course
Plaques and Experiments
Watch next
Master Plaques and Experiments with a bite sized video explanation from Kylia
Start learningRelated Videos
Related Practice
Textbook Question
530
views