Bacteriophage Life Cycles Quiz

Questions and Answers

What is the first step in the life cycle of bacteriophages?

Synthesis

Entry/Penetration

Attachment (correct)

Release

During which phase of the virus life cycle is the viral genome replicated?

Synthesis (correct)

Entry/Penetration

Assembly

Release

What happens to the host cell during the release phase of the lytic cycle?

It is killed. (correct)

It divides into two cells.

It is transformed into a virus.

It remains unharmed.

Which term describes the viral genome when it is integrated into the host cell's chromosome during lysogeny?

Prophage Signup and view all the answers

What is a key factor that influences whether a phage will follow the lytic cycle or the lysogenic cycle?

The availability of nutrients in the host cell. Signup and view all the answers

What is produced during the assembly phase of the bacteriophage life cycle?

New viruses Signup and view all the answers

What type of cycle ends in the lysis of the host cell?

Lytic Cycle Signup and view all the answers

Why is lysogeny considered a survival strategy for bacteriophages?

It permits the virus to remain dormant until conditions improve. Signup and view all the answers

In lysogeny, what happens to the prophage during cell division?

It is replicated with the host cell DNA. Signup and view all the answers

In the context of bacteriophage life cycles, what does 'entry' specifically refer to?

The genome of the phage being injected into the host cell. Signup and view all the answers

What is the first step in the animal virus life cycle?

Adsorption Signup and view all the answers

Which process specifically describes animal viruses integrating their genome into the host cell chromosome?

Latency Signup and view all the answers

How do animal viruses enter host cells compared to bacteriophages?

By having their capsid enter the host cell Signup and view all the answers

Which step involves stripping off the capsid to free the viral genome in the animal virus life cycle?

Uncoating Signup and view all the answers

What determines whether an animal virus is naked or enveloped?

The viral envelope surrounding the capsid Signup and view all the answers

During which step are new viral particles assembled?

Assembly Signup and view all the answers

What happens during the synthesis phase of the animal virus life cycle?

The viral genome is replicated and proteins are made Signup and view all the answers

What is a key difference between the life cycles of bacteriophage and animal viruses?

Animal viruses can integrate their genome into host chromosomes Signup and view all the answers

Which part of the virus provides a means to attach to host cell receptors?

Spikes Signup and view all the answers

In the context of viral infections, what does the term 'lysis' refer to?

Release of new viruses that destroy the host cell Signup and view all the answers

Match the steps of the lytic cycle with their descriptions:

Attachment = Spikes attach to host cell receptors Entry/Penetration = Phage injects its genome into the host cell Synthesis = Host cell replicates viral genome and proteins Release = New viruses are released by lysing the host cell Signup and view all the answers

Match the terms related to bacteriophage cycles with their definitions:

Lytic Cycle = Cycle ending in the lysis of the host cell Lysogenic Cycle = Cycle where viral genome integrates into host DNA Prophage = Integrated viral genome in host chromosome Host cell = Cell that is infected by a virus Signup and view all the answers

Match the phases of the lysogenic cycle with their outcomes:

Integration = Viral genome becomes part of host DNA Replication = Host cell replicates its own DNA along with prophage Induction = Prophage exits the host chromosome Dormancy = Viral genome remains inactive within host Signup and view all the answers

Match the actions of a bacteriophage during infection with their corresponding steps:

Injecting genome = Occurs during Entry/Penetration Producing capsids = Occurs during Assembly Attaching to cell = Occurs during Attachment Releasing new viruses = Occurs during Release Signup and view all the answers

Match the factors influencing bacteriophage cycle choice with their descriptions:

Host health = Determines cycle preference between lytic and lysogenic Nutrient availability = Affects the decision to enter lysogeny Prophage replication = Occurs during lysogenic cycle Cell lysis = A result of the lytic cycle Signup and view all the answers

Match the following outcomes with their respective phage cycle:

Lytic Cycle = New viruses kill the host cell Lysogenic Cycle = Viral genome is dormant in host Induction = Prophage reverts to lytic cycle Persistence = Host cell divides with the prophage Signup and view all the answers

Match the steps of viral replication with their functions:

Attachment = Establishes connection with host Synthesis = Produces components needed for new viruses Assembly = Forms new viral particles Release = Expels new viruses from the host cell Signup and view all the answers

Match the cycle characteristics with their corresponding terms:

Lytic = Rapid viral reproduction and cell death Lysogenic = Prophage can lead to future lytic cycles Bacteriophage = Virus that infects bacteria Capsid = Protein shell that encases viral genome Signup and view all the answers

Match the phases of the viral life cycle with the corresponding actions:

Entry = Genome is delivered into the host Assembly = Components are organized into new viruses Release = Viruses exit the host and spread Synthesis = Host machinery is used for viral production Signup and view all the answers

Match the steps in the animal virus life cycle with their descriptions:

Adsorption = Spikes on the virus attach to host cell receptors Entry/Penetration = The viral capsid enters the host cell Uncoating = The capsid is stripped off to free the viral genome Release = The new viruses leave the host cell Signup and view all the answers

Match the terminology to its correct description in viral life cycles:

Lytic cycle = Ends in the destruction of the host cell Lysogeny = Viral genome integrates into the host cell's chromosome Latency = Dormant phase for animal viruses Synthesis = Replication of the viral genome and production of proteins Signup and view all the answers

Match the type of virus to its entry mechanism:

Naked virus = Enters without a membrane Enveloped virus = Requires fusion with the host cell membrane Bacteriophage = Injects its chromosome into the host cell Animal virus = Fully enters with capsid and genome Signup and view all the answers

Match the virus types to their specific characteristics:

Bacteriophage = Only infects bacterial cells Animal virus = Involves uncoating during replication Lysogenic phage = Can integrate into the host chromosome Naked virus = Lacks a lipid envelope Signup and view all the answers

Match the term to its relevant concept in viral replication:

Viral proteins = Produced during the synthesis phase Capsid = Protective protein coat of the virus Prophage = Integrated viral genome in bacterial cells Virus spikes = Facilitate attachment to host cells Signup and view all the answers

Match the viral characteristics to their impact on the host:

Release phase = Can cause cell death during lytic cycle Latency = Allows persistence of viral genome without replication Infection = Can cause cell stress and mutations Synthesis = Demands host cell resources to replicate Signup and view all the answers

Match the phase of viral replication to its outcome:

Assembly = New viral particles are formed Entry = Virus enters the host cell Uncoating = Virus genome is made accessible Release = Viruses exit the host cell Signup and view all the answers

Match the following types of viruses with their entry differences:

Naked viruses = Enter through endocytosis or direct penetration Enveloped viruses = Fuse with host cell membrane Bacteriophages = Use tail fibers to inject DNA Animal viruses = Enter fully with the capsid Signup and view all the answers

Match the viral life cycle terms to their definitions:

Lytic cycle = Immediate replication and release of new virions Lysogenic cycle = Viral DNA is incorporated into host DNA Uncoating = Release of viral genome from the capsid Capsid = The protein shell encapsulating viral genetic material Signup and view all the answers

What occurs during the lytic cycle of bacteriophages?

The bacteriophage actively replicates and destroys the host cell. Signup and view all the answers

What characterizes the lysogenic cycle of bacteriophages?

The bacteriophage's DNA remains inactive within the bacterial DNA. Signup and view all the answers

What is referred to as a prophage?

The integrated viral DNA within bacterial DNA. Signup and view all the answers

Which type of bacteriophage primarily follows the lysogenic pathway?

Temperate phages Signup and view all the answers

What triggers the switch from the lysogenic cycle to the lytic cycle?

Environmental stressor conditions. Signup and view all the answers

During which phase of the lytic cycle does the host cell burst?

Release phase Signup and view all the answers

How does the lytic cycle affect the host bacteria?

It causes the bacteria to die and release viral particles. Signup and view all the answers

What is the key distinction between lytic and lysogenic cycles?

Lytic cycle produces viral particles; lysogenic does not. Signup and view all the answers

Which of the following best describes the infection process of bacteriophages?

Bacteriophages attach and inject their DNA into the host bacteria. Signup and view all the answers

What role does the bacteriophage's ability to control the host's machinery play in the lytic cycle?

It allows the bacteriophage to replicate its DNA efficiently. Signup and view all the answers

Match the following features with their corresponding phage cycle:

Lytic Cycle = Produces many viral particles Lysogenic Cycle = Prophage remains dormant in host Signup and view all the answers

Match the following terms with their definitions:

Temperate Phages = Phages that follow the lysogenic pathway Virulent Phages = Phages that primarily undergo the lytic cycle Prophage = Integrated viral DNA within a bacterial genome Lysis = The bursting of the host cell to release viruses Signup and view all the answers

Match the following steps of the bacteriophage infection process with their descriptions:

Attachment = Bacteriophage binds to bacterial cell Injection = Delivery of viral DNA into the host Replication = Viruses make copies using host machinery Release = New phages exit the host cell after lysis Signup and view all the answers

Match the following characteristics with the correct cycle:

Lytic Cycle = High viral yield at very end Lysogenic Cycle = No immediate symptoms in the host Signup and view all the answers

Match the cycle effects with how they impact the bacterial host:

Lytic Cycle = Destroys host's DNA Lysogenic Cycle = Promotes host multiplication with viral DNA Signup and view all the answers

Match the following phases of the cycle with their outcomes:

Lytic Cycle = Host cell bursting Lysogenic Cycle = Dormancy of phage Transition Phase = Switch from lysogenic to lytic Signup and view all the answers

Match the following scenarios with their corresponding phage cycle:

Viral DNA integrates into host DNA = Lysogenic Cycle Host cell immediately dies producing phages = Lytic Cycle Virus lies dormant until triggered = Lysogenic Cycle Rapid production of viral particles = Lytic Cycle Signup and view all the answers

Match the following actions of bacteriophages with their corresponding cycle:

Injecting DNA = Common to both cycles Integrating DNA = Specific to lysogenic cycle Replicating DNA = Specific to lytic cycle Lysing host cell = Exclusive to lytic cycle Signup and view all the answers

Match the consequences of each cycle with the results:

Lytic Cycle = Release of numerous phages Lysogenic Cycle = Prophage replicates with host genome Signup and view all the answers

What is the role of viral genetic material in the replication process?

It contains essential instructions for virus replication. Signup and view all the answers

How do viruses evade the host immune system once they have exited the host cell?

By acquiring pieces of the host cell membrane to form an envelope. Signup and view all the answers

What is a consequence of new viruses exiting the host cell?

The host cell often dies as a result of the viral replication process. Signup and view all the answers

Why is understanding the virus life cycle important for antiviral drug development?

It helps in identifying specific stages of the replication cycle that can be targeted. Signup and view all the answers

What specificity do viruses have concerning the types of cells they infect?

They are specific to certain cell types based on receptor patterns. Signup and view all the answers

What process do host cell machinery perform when a virus infects it?

It translates RNA instructions into viral components. Signup and view all the answers

Which statement best describes how viral envelopes are formed?

They form by acquiring parts of the host cell membrane upon exit. Signup and view all the answers

Match the following viral structures with their functions:

Capsid = Protects viral genetic material Envelope = Aids in evading the immune system Spike proteins = Facilitates attachment to host cells Nucleic acid = Carries genetic instructions for replication Signup and view all the answers

Match the different types of viral genetic material with their characteristics:

DNA = Stable and double-stranded RNA = Often single-stranded and less stable Circular DNA = Typically found in some viral families Segmented RNA = Comprises multiple independent pieces Signup and view all the answers

Match the stages of viral infection with their corresponding actions:

Attachment = Virus binds to host cell receptors Penetration = Virus enters the host cell Replication = Host cell machinery synthesizes viral components Release = New viruses exit the host cell Signup and view all the answers

Match the following terms related to viral replication with their definitions:

Lysis = Destruction of the host cell Infection = Entry of the virus into the host cell Translation = Process of synthesizing viral proteins Transcription = Conversion of viral DNA to RNA Signup and view all the answers

Match the following terms with their roles in the viral life cycle:

Viral entry = Initiates infection Host cell machinery = Synthesizes viral components Viral assembly = Formation of new virus particles Evading the immune response = Enhances survival of the virus Signup and view all the answers

Match the stages of the viral replication cycle with their corresponding outcomes:

Attachment = Virus binds to specific cells Entry = Virus enters the host cell Replication and assembly = New viral components are created Release = New viruses infect other cells Signup and view all the answers

Match the following viruses with their notable characteristics:

Enveloped viruses = Acquire host cell membrane during release Naked viruses = Lack a lipid envelope Retroviruses = Convert RNA to DNA in host Bacteriophages = Target bacterial cells specifically Signup and view all the answers

Study Notes

Bacteriophage Life Cycle

Attachment: Virus spikes connect to receptors on the host cell surface.
Entry/Penetration: The phage injects its genetic material (RNA or DNA) into the host; the phage body remains outside.
Synthesis: Host cell ribosomes produce viral proteins while host enzymes replicate the viral genome.
Assembly: Newly formed viral genomes are packed into capsids inside the host cell.
Release: New viruses burst out of the host cell, leading to its death; this process initiates the Lytic Cycle.
Lysogeny: Some bacteriophages can integrate their genome into the host chromosome (prophage) and replicate with it during cell division.
Decision Process: The cycle chosen (lytic or lysogenic) depends on host cell health—nutrient-rich conditions favor lysogeny, while stressed conditions prompt lytic cycle activation.
Lytic vs. Lysogenic: Not all bacteriophages can enter lysogeny; some are strictly lytic.

Animal Virus Life Cycle

Terminology: "Bacteriophage" refers specifically to bacteria-infecting viruses, while animal viruses have distinct terminology and mechanisms.
Cell Complexity: Eukaryotic animal cells are structurally more complex than bacterial cells, leading to varied replication processes.
Entry Mechanism: Unlike bacteriophages, animal viruses enter the cell with their entire capsid, necessitating an additional step for capsid uncoating.
Latency: The phenomenon of viral DNA integration in animal cells is termed latency, contrasting with lysogeny in bacteriophages.
Adsorption: Virus spikes attach to receptors on animal host cells similarly to bacteriophages.
Entry/Penetration: Viral capsid enters the host cell, with variations in entry method between naked and enveloped viruses.
Uncoating: Capsid removal exposes the viral genome for replication.
Synthesis: Viral genome replication and protein production occur through host cellular machinery.
Assembly: Viral genomes are loaded into new capsids for the formation of new virus particles.
Release: New viruses exit the host cell, with methods of release differing between naked and enveloped viruses.

Bacteriophage Life Cycle

Attachment: Virus spikes connect to receptors on the host cell surface.
Entry/Penetration: The phage injects its genetic material (RNA or DNA) into the host; the phage body remains outside.
Synthesis: Host cell ribosomes produce viral proteins while host enzymes replicate the viral genome.
Assembly: Newly formed viral genomes are packed into capsids inside the host cell.
Release: New viruses burst out of the host cell, leading to its death; this process initiates the Lytic Cycle.
Lysogeny: Some bacteriophages can integrate their genome into the host chromosome (prophage) and replicate with it during cell division.
Decision Process: The cycle chosen (lytic or lysogenic) depends on host cell health—nutrient-rich conditions favor lysogeny, while stressed conditions prompt lytic cycle activation.
Lytic vs. Lysogenic: Not all bacteriophages can enter lysogeny; some are strictly lytic.

Animal Virus Life Cycle

Terminology: "Bacteriophage" refers specifically to bacteria-infecting viruses, while animal viruses have distinct terminology and mechanisms.
Cell Complexity: Eukaryotic animal cells are structurally more complex than bacterial cells, leading to varied replication processes.
Entry Mechanism: Unlike bacteriophages, animal viruses enter the cell with their entire capsid, necessitating an additional step for capsid uncoating.
Latency: The phenomenon of viral DNA integration in animal cells is termed latency, contrasting with lysogeny in bacteriophages.
Adsorption: Virus spikes attach to receptors on animal host cells similarly to bacteriophages.
Entry/Penetration: Viral capsid enters the host cell, with variations in entry method between naked and enveloped viruses.
Uncoating: Capsid removal exposes the viral genome for replication.
Synthesis: Viral genome replication and protein production occur through host cellular machinery.
Assembly: Viral genomes are loaded into new capsids for the formation of new virus particles.
Release: New viruses exit the host cell, with methods of release differing between naked and enveloped viruses.

Bacteriophages Overview

Bacteriophages are specialized viruses that target and infect bacteria.
They can operate via two distinct infection cycles: the lytic cycle and the lysogenic cycle.

Infection Process

Initiation involves the bacteriophage attaching to the outer surface of a bacterial cell, followed by the injection of its viral DNA.
This attachment and DNA injection is a shared initial phase in both lytic and lysogenic cycles.

Lytic Cycle

Known as the reproductive cycle, where the phage actively replicates its DNA within the bacterial host.
The bacteriophage can destroy the bacterial host's DNA, commandeering the cell's machinery for viral production.
This cycle culminates in the production of numerous viral particles.
Host bacterial cell undergoes lysis, resulting in its rupture and the release of new phages.
The lytic cycle is characterized by the death of the bacterial host.

Lysogenic Cycle

In the lysogenic cycle, the bacteriophage integrates its DNA into the bacterial genome, forming a prophage.
The bacterial cells can continue to divide and replicate while carrying the integrated viral DNA without producing new viral particles.
This cycle represents a dormant phase for the virus, allowing bacteria to survive.

Transition Between Cycles

Environmental changes or specific triggers can prompt bacteria to activate the viral DNA, shifting the infection from the lysogenic cycle to the lytic cycle.
Temperate phages are those that primarily follow the lysogenic pathway, while virulent phages predominantly engage in the lytic cycle.

Important Distinctions

The lytic cycle results in viral particle production and the destruction of the host bacteria.
The lysogenic cycle allows for the coexistence of viral DNA within the bacterial genome, without immediate viral production, enabling the host bacteria to survive.

Bacteriophages Overview

Bacteriophages are specialized viruses that target and infect bacteria.
They can operate via two distinct infection cycles: the lytic cycle and the lysogenic cycle.

Infection Process

Initiation involves the bacteriophage attaching to the outer surface of a bacterial cell, followed by the injection of its viral DNA.
This attachment and DNA injection is a shared initial phase in both lytic and lysogenic cycles.

Lytic Cycle

Known as the reproductive cycle, where the phage actively replicates its DNA within the bacterial host.
The bacteriophage can destroy the bacterial host's DNA, commandeering the cell's machinery for viral production.
This cycle culminates in the production of numerous viral particles.
Host bacterial cell undergoes lysis, resulting in its rupture and the release of new phages.
The lytic cycle is characterized by the death of the bacterial host.

Lysogenic Cycle

In the lysogenic cycle, the bacteriophage integrates its DNA into the bacterial genome, forming a prophage.
The bacterial cells can continue to divide and replicate while carrying the integrated viral DNA without producing new viral particles.
This cycle represents a dormant phase for the virus, allowing bacteria to survive.

Transition Between Cycles

Environmental changes or specific triggers can prompt bacteria to activate the viral DNA, shifting the infection from the lysogenic cycle to the lytic cycle.
Temperate phages are those that primarily follow the lysogenic pathway, while virulent phages predominantly engage in the lytic cycle.

Important Distinctions

The lytic cycle results in viral particle production and the destruction of the host bacteria.
The lysogenic cycle allows for the coexistence of viral DNA within the bacterial genome, without immediate viral production, enabling the host bacteria to survive.

Virus Overview

Infectious particles that hijack host cells for replication, similar to computer viruses.
They utilize the cellular machinery of the host to produce new viruses.

Infection Mechanics

Viruses show specificity to certain cell types, determined by receptor patterns on those cells.
Unique protein receptors on the surface of cells are targeted by viruses for successful entry.

Genetic Material

Viral genetic material can be DNA, which is structurally simpler than cellular DNA.
Contains crucial instructions necessary for the replication of the virus.
Inside host cells, viral DNA is transcribed into RNA to facilitate protein synthesis.

Assembly and Release

Host cellular machinery translates viral RNA into various viral components.
Newly constructed virus parts assemble within the host cell.
Completion of assembly often leads to cell death as viruses exit the host to infect new cells.

Viral Envelopes

Emerging viruses may acquire portions of the host cell membrane, leading to the formation of an envelope.
This protective envelope aids in evading the host's immune system responses.

Replication Cycle

Newly formed viruses have the potential to infect additional host cells, sustaining the replication cycle.
Insights into the virus life cycle have guided the creation of antiviral drugs that target specific replication stages.

Virus Overview

Infectious particles that hijack host cells for replication, similar to computer viruses.
They utilize the cellular machinery of the host to produce new viruses.

Infection Mechanics

Viruses show specificity to certain cell types, determined by receptor patterns on those cells.
Unique protein receptors on the surface of cells are targeted by viruses for successful entry.

Genetic Material

Viral genetic material can be DNA, which is structurally simpler than cellular DNA.
Contains crucial instructions necessary for the replication of the virus.
Inside host cells, viral DNA is transcribed into RNA to facilitate protein synthesis.

Assembly and Release

Host cellular machinery translates viral RNA into various viral components.
Newly constructed virus parts assemble within the host cell.
Completion of assembly often leads to cell death as viruses exit the host to infect new cells.

Viral Envelopes

Emerging viruses may acquire portions of the host cell membrane, leading to the formation of an envelope.
This protective envelope aids in evading the host's immune system responses.

Replication Cycle

Newly formed viruses have the potential to infect additional host cells, sustaining the replication cycle.
Insights into the virus life cycle have guided the creation of antiviral drugs that target specific replication stages.

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Description

This quiz explores the life cycle of bacteriophages, focusing on the steps involved from infection to the release of new viruses. Understand how these viruses infect bacterial cells and reproduce, contributing to the cycle of infection.