Viruses Flashcards
Exam 1
Intracellular parasite
Needs a host cell to live and reproduce
Virus
ultramicroscopic parasitic infecting cells of various organisms
Viral Specificity
ability of viral particles to infect specific host cell (will infect me but not my dog); has to have capacity to attach itself to membrane of host cell
Viral Particle Activity
inactive until infect host cell, then become active
2 Types of Viral Specificity (list & definitions)
Inter-specificity: infection between different cells
Intra-specificity: infection within specific cell of the body
2 Components of a Virus
viral genome and viral protein molecule (capsid)
Viral Genome
genetic material of virus, can be DNA or RNA; composed of nucleotide
Capsid
protein coat surrounding viral genome; made of capsomers
Nucleocapsid
another name for virus (protein coat surrounding genetic material)
Capsomer
identical subunits of protein molecules that compose virus capsid
Envelope
additional outer covering (extra capsid) of some viruses
What are viruses without envelopes called?
naked virus
4 Different shapes of Viruses
simple; complex (w/tail); helical (helix is capsid); icosahedral
Bacteriophage
virus that infects bacteria
Coliphage
virus affecting E. coli (bacteriophage)
Sheath
retractable area of a coliphage virus (bacteriophage)
Tail Pins
components of virus aligning with host cell membrane for infection
“Some”
body/unit
“Cyte”
cellular unit/cell
What are the 2 Viral Life Cycles?
Lytic Cycle; Lysogenic Cycle
Lysis
to break down/destroy (destructive)
Lytic Cycle (Steps)
Virulent (destructive);
Steps:
1. Attachment(Adsorption)
2. Entry(Penetration): inject genome into host cell OR enter host cell
3. Uncoat the capsid
4. Integrate viral genome with host cell
5. Biosynthesize genome and protein
6. Assemble genomes and capsids together (Virion)
7.Release (most likely enveloped and spiked)
Virulent factor
degree to which something is destroying something else
Virion
newly assembled virus with capacity to infect nearby cells
When do spikes develop on a virus?
when the Virion exits host cell
Lysogenic Cycle (Steps)
- Attachment(Adsorption)
- Entry(Penetration)
- Uncoat capsid
- Integrate into host DNA (Prophage/provirus)
Prophage
virus when it integrates into host DNA during lysogenic cycle (AKA provirus)
Lysogenic Conversion
virus lays dormant until stress or illness activates them to multiply (lytic cycle continues)
Example of a Persistent Infection (Explain)
Chicken pox; a person can survive it as a child. The turns 30, becomes stressed and develops shingles
Viral Classification: Order (Name ends with, how many, examples(3))
Virales; 3; Caudaovirales; Mononegavirales; Nidovirales
Viral Classification: Family (Name ends with, how many)
Viridae; 63
Viral Classification: Genus (Name ends with, how many, example)
Virus; 263; Herpes Simplex Virus (HSV)
Viral Classification: Species (Naming system, how many, example)
numerous
name: type -> class -> A - E
Ex: HSV-1 (Influenza A)
What can Human Papilloma virus (HPV) develop into?
cervical cancer or anal cancer
What can Hep B develop into?
liver cirrhosis (cancer)
What can Epstein Barr Virus develop into?
Burkitt’s Lymphoma
List the transformation of a normal cell into a cancer cell
Normal cell -> Viral Cell -> transformed cell -> tumor cell -> cancer cell (benign OR malignant)
What the cytopathic effects a cell must undergo to become a transformed cell? (6)
change in shape and size; multinucleated cells; cell lysis(break up); cell fusion; increase in granules; alteration of gene(DNA)
Syncytium
fusion of normal cells
What is the function of granules in cells?
store proteins and nutrients
Benign Cancer Cell
localized at one point; does not replicate; usually isn’t harmful
Malignant Cancer Cell
metastasizes (spreads)
Special Types of Viruses (List)
Complex; Prions; Satellite Viruses; Viroid
Complex viruses (example)
capsid not composed of proteins, rather lipoproteins
Ex: pox virus (chicken pox, monkey pox, small pox)
Prions
no genome, rather malformed and misfolded protein molecules; cause neurodegenerative diseases (Encephalopathies)
What disease can Prions cause?
neurodegenerative diseases (Encephalopathies)
Ex: Bovine Spongiform Encephalopathy (BSE)
Bovine Spongiform Encephalopathy Animal Infection Examples
Cow: Mad Cow Disease
Goats and Sheep: Scrapie Disease
Elk: Wasting Disease
Humans: Creutzfield Jakob Syndrome (CJS)
Satellite Viruses (examples (2))
dependent viruses- will not infect someone unless they are already infected by another virus
Ex: Delta Agent Virus (will only infect if already have Hep B) - Now called Hep D
Ex: Adeno Associated Virus (AAV) - only if infected with Adenovirus)
Viroid
plant virus; no protein, rather small pieces of naked RNA genome
Viral infection is the cause of most what?
acute infections; when illness has unknown affliction, usually blame it on viruses
Viral Treatment
symptoms (rest, pump with fluids); anti-viral drugs
Diagnosis for Viruses
test for antibody to the virus
Central Dogma of Life
Everything we do starts with DNA; DNA gives instructions (transcription) to RNA, RNA then secretes (translation) to appropriate protein molecule
Morbidity
number of species that are infected in a population
Genetic engineering
manipulation of the gene (plasmid)
What type of virus secretes reverse transcriptase?
Retrovirus (HIV)
What type of viral strand uses viral RNA and immediately translates to viral protein?
positive-sense single-strand RNA (pos-sense ssRNA)
Negative-sense single strand RNA
Viral RNA converts to +ssRNA then synthesizes to V-protein
