Exploring the Lytic and Lysogenic Life Cycles of Bacteriophages

Abstract

The goal of this lesson is to introduce students to the lytic and lysogenic cycles of T4 and lambda bacteriophages, respectively, using student-centered pedagogies. Bacteriophages are viruses that infect bacteria and are either virulent or temperate; virulent phages can only undergo the lytic cycle, which results in death of the host cell, while temperate phages can undergo either the lytic or lysogenic cycle, the latter of which results in the long-term association between host and virus. Bacteriophages significantly affect bacterial population in nature and are even attractive therapeutic interventions for some bacterial infections in humans. Therefore, this lesson was designed to educate students about the structure and function of bacteriophages and how viral infections can impact bacterial populations. The learning goals of this lesson are to understand how the lytic and lysogenic cycles of bacteriophages vary, affect bacterial growth, and are dictated by their unique genomes. To this end, the lesson incorporates a homework assignment for students before class, a series of in-class activities and critical thinking scenarios, and a homework assignment after class. This lesson was successfully employed in an upper-level undergraduate virology course for biology majors. Students were enthusiastic and expressed thoughtful and educated ideas during class discussion and through answers to open-ended questions. Taken together, this lesson provides an interactive and studentcentered approach to studying the form and function of bacteriophages, the most abundant organisms in the biosphere. Citation: Joy JP. 2021. Exploring the lytic and lysogenic life cycles of bacteriophages. CourseSource. https://doi.org/10.24918/cs.2021.6 Editor: Sue Merkel, Cornell University Received: 7/23/2020; Accepted: 11/19/2020; Published: 3/2/2021 Copyright: © 2021 Joy. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited. The author affirms that they either own the copyright to, utilize images under the Creative Commons Attribution 4.0 License, or have received written permission to use the text, figures, tables, artwork, abstract, summaries and supporting materials. Conflict of Interest and Funding Statement: The author does not have a financial, personal, or professional conflict of interest related to this work. Supporting Materials: Supporting File S1. Lytic and lysogenic – Bacteriophages in Medicine Pre-Class Homework Assignment; S2a. Lytic and lysogenic – Bacteriophage Replication Cycles In-Class Worksheet Section 1; S2b. Lytic and lysogenic – Bacteriophage Replication Cycles In-Class Worksheet Section 2; S2c. Lytic and lysogenic – Bacteriophage Replication Cycles In-Class Worksheet Section 3; S2d. Lytic and lysogenic – Bacteriophage Replication Cycles In-Class Worksheet Section 4; S3. Lytic and lysogenic – In-Class Lecture; S4. Lytic and lysogenic – In-Class Strip Sequence; S5. Lytic and lysogenic – Post-class Homework Assignment; S6. Lytic and lysogenic – Bacteriophages in Medicine Pre-Class Homework Assignment Answer Key; S7. Lytic and lysogenic – Bacteriophage Replication Cycles In-Class Worksheet Answer Key; and S8. Lytic and lysogenic – Post-class Homework Assignment Answer Key. *Correspondence to: JaimyPJoy@gmail.com CourseSource | www.coursesource.org 2021 | Volume 08 1 Lesson