BIOL 3340 Lecture Notes - Chapters 25 & 26

Vocabulary flashcards for key terms from the lecture notes.

Viruses

Small obligate intracellular parasites

Virion

A virus particle that delivers its RNA or DNA genome into a host cell

Capsid

Outer protein shell of a virus

Nucleocapsid

Nucleoprotein and the genome of a virus

Enveloped Viruses

Viruses with a phospholipid bilayer surrounding the nucleocapsid

Baltimore System

Classification system based on genetic material present in the virion

Morphology

Describes the size and shape, chemical composition, and structure of genome of a virus

Helical

Nucleocapsids with capsid proteins wrapped around nucleic acid

Icosahedral

Nucleocapsids of spherical viruses

Complex Viruses

Viruses with a head and tail structure

Sense

Genomic RNA strand of single stranded RNA viruses

+sense viral RNA

Viral RNA identical to viral mRNA

Antisense/Negative Sense RNA

RNA complementary to mRNA

7 Steps of Viral Multiplication/Replication

Attachment/Adsorption, Entry, Uncoating, Replication/Synthesis, Assembly, Maturation, Release

Infection

A microbe growing and multiplying on or within a host

Infectious Disease

Any change from a state of health

Pathogenicity

Ability of a pathogen to cause disease

Virulence

Degree of harm (pathogenicity) inflicted on the host

Extracellular Pathogens

Pathogens that grow outside host cells in tissues and fluids

Intracellular Pathogens

Pathogens that grow and multiply within host cells

Facultative Intracellular Pathogens

Pathogens that reside within the cells of the host or in the environment but can also be grown in pure culture without host cell support

Obligate Intracellular Pathogens

Pathogens that only grow when inside host cells

Incubation Period

Period after pathogen entry, before signs and symptoms

Prodromal Stage

Onset of signs and symptoms of a disease

Illness Period

Period when disease is most severe, displays signs and symptoms

Convalescence

Signs and symptoms begin to disappear; recovery

Signs

Objective changes in the body that can be directly observed

Symptoms

Subjective changes experienced by patient

Disease Syndrome

Set of characteristic signs and symptoms for a disease

Zoonoses

Infections passed from animal to human

Reservoir

Natural environmental location in which the pathogen normally resides and multiplies

Vector

Organism that spreads disease from one host to another

Vertical Transmission

Transmission from pregnant women to their unborn child

Infectious Dose 50 (ID50)

Number of pathogens that will infect 50% of inoculated hosts

Lethal Dose 50 (LD50)

Dose that kills 50% of experimental animals within a specified period

Adhesins

Special molecules that mediate adherence

Colonization

Establishing a site of microbial replication on or within a host

Infectivity

Ability to create a discrete point of infection

Invasiveness

Ability to spread to adjacent tissues

Bacteremia

Presence of viable bacteria in the blood

Septicemia

Bacterial or fungal toxins in the blood

Exotoxins

Soluble, heat-labile proteins

AB Toxins

Composed of A subunit (toxic effect) and B subunit (binds to target cell)

Endotoxin

Lipopolysaccharide (LPS) in Gram-negative cell wall

Mycotoxins

Toxins produced by fungi

Epidemiology

Science that evaluates occurrence, determinants, distribution, and control of health and disease in a defined human population

Sporadic Disease

Occurs occasionally and at irregular intervals

Endemic Disease

Maintains a relatively steady low-level frequency at a moderately regular interval

Hyperendemic Diseases

Gradually increase in frequency above endemic level but not to epidemic level

Outbreak

Sudden, unexpected occurrence of disease/Usually focal or in a limited segment of population