Viral Replication: Exploring Lytic and Lysogenic Cycles

Biology Grades High School 3:54 Video
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Lesson Description

This lesson explores the two primary methods viruses use to replicate: the lytic and lysogenic cycles. Students will learn how viruses hijack host cells, replicate their genetic material, and spread, with a focus on the implications for understanding viral infections.

Video Resource

Lytic and lysogenic cycles | Viruses | High school biology | Khan Academy

Khan Academy

Duration: 3:54
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Key Concepts

  • Lytic Cycle: Viral replication resulting in host cell lysis.
  • Lysogenic Cycle: Viral DNA integration into the host genome.
  • Viral Replication: The process by which viruses create copies of themselves within a host cell.
  • Integration: the way a virus will insert itself into the organism's DNA

Learning Objectives

  • Students will be able to compare and contrast the lytic and lysogenic cycles.
  • Students will be able to explain how viruses use host cell machinery for replication.
  • Students will be able to describe the potential impacts of viral replication on a host organism.
  • Students will be able to describe how environmental factors may affect a virus.

Educator Instructions

  • Introduction (5 mins)
    Begin by asking students what they know about viruses and how they make us sick. Briefly discuss the importance of understanding viral replication for developing treatments and preventative measures.
  • Video Viewing (10 mins)
    Play the Khan Academy video 'Lytic and lysogenic cycles | Viruses | High school biology | Khan Academy'. Encourage students to take notes on the key differences between the two cycles.
  • Lytic Cycle Discussion (10 mins)
    Discuss the lytic cycle, focusing on the steps: attachment, entry, replication, assembly, and lysis. Use diagrams to illustrate the process.
  • Lysogenic Cycle Discussion (10 mins)
    Discuss the lysogenic cycle, emphasizing the integration of viral DNA into the host genome and its implications for long-term infection. Explain how the lysogenic cycle can switch to the lytic cycle.
  • Comparison Activity (10 mins)
    Have students work in pairs to create a Venn diagram comparing and contrasting the lytic and lysogenic cycles. Focus on key differences and similarities.
  • Wrap-up and Q&A (5 mins)
    Summarize the key concepts and answer any remaining questions from students.

Interactive Exercises

  • Cycle Modeling
    Students will create a physical model (using clay, pipe cleaners, etc.) or a digital animation to illustrate either the lytic or lysogenic cycle, labeling the key steps and components.

Discussion Questions

  • What are the advantages and disadvantages for a virus to use the lytic cycle versus the lysogenic cycle?
  • How could understanding the lytic and lysogenic cycles help in developing antiviral drugs?
  • Can you think of any real-world examples of viruses that use each of these cycles?
  • How do environmental factors play a role in the viral cycle?

Skills Developed

  • Critical Thinking
  • Scientific Modeling
  • Data Interpretation
  • Scientific Communication

Multiple Choice Questions

Question 1:

In the lytic cycle, what happens to the host cell?

Correct Answer: It bursts and releases new viruses.

Question 2:

Which cycle involves the integration of viral DNA into the host cell's DNA?

Correct Answer: Lysogenic cycle

Question 3:

What is the main purpose of both the lytic and lysogenic cycles?

Correct Answer: To replicate the virus's DNA.

Question 4:

Which of the following cellular structures does a virus hijack to replicate its DNA?

Correct Answer: Ribosomes

Question 5:

What might trigger a virus in the lysogenic cycle to enter the lytic cycle?

Correct Answer: Stress or environmental change

Question 6:

Which cycle results in immediate cell death?

Correct Answer: Lytic Cycle

Question 7:

Which genetic material will be copied along with the host's DNA in the lysogenic cycle?

Correct Answer: Viral DNA

Question 8:

What is the process of the cell bursting called?

Correct Answer: Lysis

Question 9:

Where does the virus integrate its genetic material in the lysogenic cycle?

Correct Answer: Host's DNA

Question 10:

What is the potential result of stress or other environmental conditions in the lysogenic cycle?

Correct Answer: Activation of the Lytic Cycle

Fill in the Blank Questions

Question 1:

The viral replication cycle that results in the bursting of the host cell is called the _________ cycle.

Correct Answer: lytic

Question 2:

In the lysogenic cycle, viral DNA integrates into the host cell's _________.

Correct Answer: genome

Question 3:

Viruses use the host cell's _________ to replicate their genetic material.

Correct Answer: machinery

Question 4:

The process of a cell bursting and releasing viruses is called _________.

Correct Answer: lysis

Question 5:

Environmental conditions, like _________, can trigger a switch from the lysogenic to the lytic cycle.

Correct Answer: stress

Question 6:

When a cell divides in the lysogenic cycle, the viral DNA is _________ along with the host cell's DNA.

Correct Answer: replicated

Question 7:

In the lytic cycle, the virus essentially _________ the host cell's functions.

Correct Answer: hijacks

Question 8:

The lysogenic cycle allows the virus to remain _________ within the host cell for an extended period.

Correct Answer: dormant

Question 9:

_________ are hijacked during the lytic cycle to produce the proteins for the virus

Correct Answer: ribosomes

Question 10:

Human DNA is believed to have a lot of leftover _________ DNA from millions of years ago.

Correct Answer: virus

Educational Standards

B.LS1.1:Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells. B.LS1.2:Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. B.LS4.5:Evaluate the evidence supporting claims that changes in environmental conditions may result in (1) increases in the number of individuals of some species, (2) the emergence of new species over time, and (3) the extinction of other species.

Teaching Materials

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