Characterizing and Classifying Viruses, Viroids, and Prions Flashcards
describe polyhedral morphology
D20 dice
Describe nucleic acid for viruses
DNA or RNA
What is the name for viruses that infect bacteria?
bacteriophage
Distinguish between a segmented genome and a genome that has only a single nucleic acid molecule.
single strand in line or in circle
segmented in separate pieces in their own capsule, allows for a lot of mutation
define envelope
A covering of lipids, carbs, and protiens. Sometimes comes from the host cell’s cell membrane
What are latent infections?
viruses that lie dormant in the body. Can become integrated in host chromosome as a “provirus” (HIV)
non integrated-chickenpox and herpes
Name the viruses given in class that are associated with human cancers.
HPV, hep B, Epstein Barr, Human Herpes Virus 8
What determines that host range for a virus?
receptors on the host cells that the virus can interact with
Define prion.
infectious proteins
Describe the lysogenic cycle of bacteriophage lambda.
bacteriophage injects DNA in bacteria, DNA is integrated into bacteria and proliferates. Can move to lytic cycle due to UV light or stress. Prophage is the name for integrated DNA
What is another name for viral particles?
virions
describe enveloped morphology
has an envelope
Describe the following methods used to cultivate animal viruses.
a. embryonated eggs
b. tissue culture
c. plaque assay (what is a plaque?)
A. injected into the membrane of the eggs to use the cells present
B. tissue broken down into cells into a single layer and virus is added
C. plaques show where viruses have destroyed the cells. Corresponds to single virion in mixture.
What special enzyme do retroviruses carry with them and what does it do?
reverse transcriptase, convert their RNA to DNA
Define viroid.
made of RNA in a free solution
define capsid
protein coat that covers the nucleic acids
Describe how animal viruses are classified.
genome structure
morphology
envelope or no
body system they affect
taxonomy
define nucleocapsid
combo of the genetic material and the capsid, sometimes intertwined
describe complex morphology
classic virus with tail fibers and base plate
Distinguish between benign and malignant tumors.
benign- abnormal growith in a localized region
malignant- abnormal growth that damages tissues and has the potential to metatisize.
What diseases are caused by prions?
mad cow disease, scrapies, variant creutzfeldt-jakob disease, chronic wasting disease in deer and elk
Name some characteristics that viruses, prions, and viroids share. How are they different?
acellular
RNA or DNA
obligate intracellular parasites
lots of reasons different
describe helical morphology
nucleic acid encapsulated by capsid that resembles a compressed helix, long rod shape.
How does the multiplication of animal viruses differ from the multiplication of bacteriophages? How is it the same?
Entry can be DNA insertion (naked viruses only), membrane fusion (envelope virus), endocytosis.
Uncoating of virus protein capsule if entire virus enters the cell
transcription can vary based on RNA or DNA, reverse transcriptase
Assembly is less complex
animal viruses do not lyse cells, they take over the cell metabolism and cell components die.
What type of organisms are infected by viroids agents?
plants
Describe penetration in the lytic cycle for T-even bacteriophages
phage injects its nucleic acids into the bacteria
describe maturation/assembly in the lytic cycle for T-even bacteriophages
creation of mature viruses inside cell
Describe attachement in the lytic cycle for T-even bacteriophages
Only happens in host range organisms and connect via H bonds with tail fibers
What is unique about the cultivation of bacteriophage?
it’s easier than animal virues.
What causes hemagglutination?
spike proteins
How are prions infectious?
bind to healthy proteins and convert it to an infectious version
define spikes
projections from the envelope that may or may not be present. used for attachment to the host
List five ways in which viruses are different that other infectious agents.
acellular
have DNA or RNA
obligate intracellular parasites
have host range
have protein coating over nucleic acids
Do segmented viruses have a single nucleic acid molecule?
no they have multiple
describe biosynthesis in the lytic cycle for T-even bacteriophages
viral nucleic acid is replicated and produces proteins needed for virus creation
describe release in the lytic cycle for T-even bacteriophages
viruses burst from cells because of sheer number or secretion of lysozyme
