Viral Replication (Ch. 13)
Name the cycle where phage DNA integrates into the host genome.
The lysogenic cycle.
What does CDC stand for? what is its purpose
Centers for Disease Control and Prevention. the CDC conducts critical science and provides health information that protects the United States against expensive and dangerous health threats
Define vurielnce
The degree of pathogenicity of a microbe (how severe the disease caused by the pathogen is)
Name the protein coat surrounding a virus.
Capsid.
Which toxin type is made of proteins and secreted by bacteria?
Exotoxins.
During which stage of the lytic cycle does the phage inject its DNA?
Penetration.
A disease constantly present in a population is called what?
Endemic.
What does LD50 measure?
The lethal dose required to kill 50% of a sample population.
What is the function of spikes on a virus?
They help in attachment to host cells.
What is Lipid A part of?
Endotoxins from the outer membrane of gram-negative bacteria.
What is a prophage?
Phage DNA that has been integrated into the host cell's chromosome.
Differentiate between incidence and prevalence.
Incidence is the number of new cases; prevalence is the total number of cases at a given time.
Which structure helps pathogens evade phagocytosis? how
Capsules. by preventing white blood cells (macrophages) from preventing phagocytosis and eliminating the pathogen,
What's the term for a fully formed infectious viral particle?
Virion.
What is a superantigen?
A type of exotoxin that triggers excessive immune response. Usually lethal.
Which cycle causes immediate lysis of the host cell? Provide me with the phases of the cycle.
The lytic cycle. Phase one (attachment) the capsid combines with a receptor in the bacterial wall. Phase 2 (penetration). Phase three (biosynthesis). Phase four (Maturation). Phase five (Release)
What type of disease transmission involves a nonliving object?
Indirect contact through a fomite.
What is the function of invasins?
They rearrange actin filaments to promote pathogen entry into host cells.
What is a viroid?
A short piece of naked RNA that infects plants.
How do IgA proteases help pathogens?
They destroy IgA antibodies, weakening mucosal immunity.
What is specialized transduction? explain
A process where specific bacterial genes are transferred by a phage due to incorrect excision of prophage DNA.
Compare and contrast the main types of disease transmission, including direct, indirect, droplet, airborne, vehicle, and vector transmission.
Direct transmission requires close contact between hosts, while indirect transmission involves intermediaries like objects or vectors; droplet transmission uses large respiratory droplets traveling short distances, whereas airborne transmission involves tiny particles that stay in the air longer and travel farther; vertical transmission occurs from mother to child during pregnancy or birth, vehicle rleies on water/food, and vector transmission relies on living carriers like mosquitoes to spread disease
Describe two mechanisms by which pathogens evade host immunity through antigenic variation.
Pathogens may change surface proteins or gene expression to avoid immune detection.
What is the difference between a sign and a symptom?
A sign is observable or measurable, while a symptom is felt by the patient.
How do A-B exotoxins disrupt host cell function at the molecular level? Include the roles of both A and B components.
The B component binds to the host cell receptor and facilitates entry, while the A component modifies host cell proteins, disrupting key cellular functions.