Podcast
Questions and Answers
What is the primary function of phage-encoded endonucleases?
What is the primary function of phage-encoded endonucleases?
What triggers the transition from the lysogenic to the lytic cycle?
What triggers the transition from the lysogenic to the lytic cycle?
What is the result of the maturation phase in the lytic cycle?
What is the result of the maturation phase in the lytic cycle?
What is the final stage of the lytic cycle?
What is the final stage of the lytic cycle?
Signup and view all the answers
What is the term for the changes in host phenotype due to the presence of a prophage?
What is the term for the changes in host phenotype due to the presence of a prophage?
Signup and view all the answers
What is the purpose of the lytic cycle for the phage?
What is the purpose of the lytic cycle for the phage?
Signup and view all the answers
What is the term for the process by which the prophage is excised from the bacterial chromosome?
What is the term for the process by which the prophage is excised from the bacterial chromosome?
Signup and view all the answers
What is the result of the transition from the lysogenic to the lytic cycle?
What is the result of the transition from the lysogenic to the lytic cycle?
Signup and view all the answers
What is the term for the phage genome when it is integrated into the bacterial chromosome?
What is the term for the phage genome when it is integrated into the bacterial chromosome?
Signup and view all the answers
What is the result of the presence of certain prophage-specific genes in the host bacterium?
What is the result of the presence of certain prophage-specific genes in the host bacterium?
Signup and view all the answers
What is the primary function of the host bacterium's cellular machinery during the lytic cycle?
What is the primary function of the host bacterium's cellular machinery during the lytic cycle?
Signup and view all the answers
What is the outcome of the degradation of the bacterial chromosome by phage-encoded endonucleases?
What is the outcome of the degradation of the bacterial chromosome by phage-encoded endonucleases?
Signup and view all the answers
What is the role of prophage-specific genes in the host bacterium?
What is the role of prophage-specific genes in the host bacterium?
Signup and view all the answers
What is the result of the presence of a prophage in bacteria such as Vibrio cholerae and Clostridium botulinum?
What is the result of the presence of a prophage in bacteria such as Vibrio cholerae and Clostridium botulinum?
Signup and view all the answers
What is the fate of the host bacterium at the end of the lytic cycle?
What is the fate of the host bacterium at the end of the lytic cycle?
Signup and view all the answers
What is the significance of the lysogenic state in the life cycle of a phage?
What is the significance of the lysogenic state in the life cycle of a phage?
Signup and view all the answers
What is the role of environmental and nutritional cues in the life cycle of a phage?
What is the role of environmental and nutritional cues in the life cycle of a phage?
Signup and view all the answers
What is the consequence of the prophage excising out of the bacterial chromosome during induction?
What is the consequence of the prophage excising out of the bacterial chromosome during induction?
Signup and view all the answers
What is the relationship between the phage genome and the host bacterium's cellular machinery during the lytic cycle?
What is the relationship between the phage genome and the host bacterium's cellular machinery during the lytic cycle?
Signup and view all the answers
What is the significance of the maturation phase in the lytic cycle?
What is the significance of the maturation phase in the lytic cycle?
Signup and view all the answers
Study Notes
Lysogenic Cycle
- Replication mode in viruses where viral DNA is replicated using the host's cellular machinery
- Viral DNA is replicated along with the host cellular DNA during host cell division
- Viruses benefit from the host cell replication machinery not distinguishing between the viral and host DNA
Lytic Cycle
- Another mode of viral replication where viral proteins are translated using host cellular processes
- Viral proteins are assembled into new virus particles and released, killing the host cell
- One lytic cycle can produce millions of virions, leading to high infectivity rates of viral diseases
Lytic vs Lysogenic Cycle
- In the lytic cycle, the virus takes over the host's systems, directs them for new virus production, and kills the host cell
- In the lysogenic cycle, the virus replicates along with the host genome without killing the host
- Lysogenic viruses integrate their genome into the host genome, forming a prophage
- Lytic cycle results in the production of new virus particles, while lysogenic cycle ends with the virus as a prophage
Bacteriophage Replication Cycle
- Bacteriophages are viruses that infect bacteria to complete their life cycle
- Discovered in 1915 by Frederick William Twort and confirmed by Felix D. Herelle in 1917
- Bacteriophages replicate in bacteria through the lytic or lysogenic cycle
Bacteriophage Structure
- Consists of a capsid head enclosing the genome, elongated sheath/tail, and tail fibers attached to the base plate
- Capsid proteins recognize specific receptors on the bacterial cell wall for attachment
- Can have different types of nucleic acid genomes (DNA or RNA) and sheath structures
Lysogenic Life Cycle
- Also known as a temperate or non-virulent infection where the phage establishes a dormant or latent stage
- Example is lambda phage, where the phage genome integrates into the bacterial chromosome
- The integrated phage genome is called a prophage, and the bacterial host is known as a lysogen
Lytic Life Cycle
- Also called a virulent phage, where the phage takes control of the host cell, replicates, and kills the host
- Steps include attachment, penetration, replication, maturation, and cell lysis to release new phages
- Results in the death of the host bacterium by bursting
Transition from Lysogenic to Lytic
- The lysogenic state can transition to the lytic cycle under certain conditions like UV light exposure or nutritional stresses
- Triggering this transition is known as induction, leading to the excision of the prophage and initiation of the lytic process
Lysogenic Conversion
- During the lysogenic cycle, specific genes from the prophage can lead to phenotypical changes in the host bacteria
- Known as lysogenic conversion, this can give rise to enhanced virulence or additional traits in the host bacteria
Lysogenic Cycle
- Replication mode in viruses where viral DNA is replicated using the host's cellular machinery
- Viral DNA is replicated along with the host cellular DNA during host cell division
- Viruses benefit from the host cell replication machinery not distinguishing between the viral and host DNA
Lytic Cycle
- Another mode of viral replication where viral proteins are translated using host cellular processes
- Viral proteins are assembled into new virus particles and released, killing the host cell
- One lytic cycle can produce millions of virions, leading to high infectivity rates of viral diseases
Lytic vs Lysogenic Cycle
- In the lytic cycle, the virus takes over the host's systems, directs them for new virus production, and kills the host cell
- In the lysogenic cycle, the virus replicates along with the host genome without killing the host
- Lysogenic viruses integrate their genome into the host genome, forming a prophage
- Lytic cycle results in the production of new virus particles, while lysogenic cycle ends with the virus as a prophage
Bacteriophage Replication Cycle
- Bacteriophages are viruses that infect bacteria to complete their life cycle
- Discovered in 1915 by Frederick William Twort and confirmed by Felix D. Herelle in 1917
- Bacteriophages replicate in bacteria through the lytic or lysogenic cycle
Bacteriophage Structure
- Consists of a capsid head enclosing the genome, elongated sheath/tail, and tail fibers attached to the base plate
- Capsid proteins recognize specific receptors on the bacterial cell wall for attachment
- Can have different types of nucleic acid genomes (DNA or RNA) and sheath structures
Lysogenic Life Cycle
- Also known as a temperate or non-virulent infection where the phage establishes a dormant or latent stage
- Example is lambda phage, where the phage genome integrates into the bacterial chromosome
- The integrated phage genome is called a prophage, and the bacterial host is known as a lysogen
Lytic Life Cycle
- Also called a virulent phage, where the phage takes control of the host cell, replicates, and kills the host
- Steps include attachment, penetration, replication, maturation, and cell lysis to release new phages
- Results in the death of the host bacterium by bursting
Transition from Lysogenic to Lytic
- The lysogenic state can transition to the lytic cycle under certain conditions like UV light exposure or nutritional stresses
- Triggering this transition is known as induction, leading to the excision of the prophage and initiation of the lytic process
Lysogenic Conversion
- During the lysogenic cycle, specific genes from the prophage can lead to phenotypical changes in the host bacteria
- Known as lysogenic conversion, this can give rise to enhanced virulence or additional traits in the host bacteria
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Learn about the lysogenic cycle, a mode of viral replication that utilizes the host's cellular machinery. Understand how viral DNA is replicated without harming the host cell.
