Quiz 3 study guide Flashcards
How large are viruses
on the scale of nm’s
Double stranded DNA virus example
Vericella-Zoster (Chicken pox/shingles)
Single stranded DNA virus example
Parvovirus (like the dog virus, but the human strain)
Arthritis in adults
Doble stranded RNA virus example
Rotavirus (#1 cause of severe diarrhea in children)
Single stranded RNA virus example
Influenza virus
COVID-19 virus
What do all viruses contain
a nucleic acid (some are RNA, some DNA, and some Single/double stranded)
What is a capsid
a protein coat sourrounding a nucleic acid- inside of all viruses
What is a capsomere
repeating protein subunits of the capsid
What is an example of a helical capsid virus
tobacco mosaic virus (Helical= rod-shaped
What is an example of a virus with a polyhedral capsid shape
Genital HPV (human papilloma virus)
- Common cause of cervical cancer
What is the most common viral structure and symmetry
Isocahedron (Polyhedral)
Complex shape example
bacteriophage (A virus that only infects bacteria)
Phage t4
Most are DS DNA viruses
Where do you find complex capsids
in bacteriophages
What is an envelope
a lipid bilayer membrane with virus-specific proteins that sourrounds the capsid of some viruses
Where is the viral envelope derived from
host cell membranes
Which virus has envelopes in every virus
influenza virus
What are spikes
glycoproteins used by some viruses to attach to the host cell (Attaches virus to host cell)
What does lysozyme do
perforates peptidoglycan, allow for nucleic acid insertion, useful for release after replication
What are nucleic acid polymerases for
for RNA viruses
What are neuraminidases
cleave glycosydic bonds in extracellular matrix, allow release
List the life cycle of a bacteriophage (Phage lytic cycle)
- Attachment, 2. Penetration, 3. Synthesis of nucleic acid and protein, 4. Assembly and packaging, 5. Release (lysis)
What is the lysogenic cycle and steps
Induction, cell division, integration
Lysogenized host cells are immune to what
reinfection by the same virus strain
What are 3 viruses that do conversion (transduction) and create toxins
Diptheria toxin, botulinum toxin, cholera toxin (All bacteria, but create toxin by transduction)
What replication always results in a dead host
lytic phage replication
What replication results in a phage integrating its DNA into the bacterial chromosome
lysogeny
How does release differ between phage and human viruses
Attachment and penetration, and release (Need to keep envelope intact in human virus b/c cannot just seperate)
Difference between phage DNA and bacteria and Viron with human cells
Only Phage DNA enters bacterium, while the entire viron enters a human cell
How does a phage release?
Always by lysis
How does a human virus release?
Can release by lysis or budding
How are viruses cultured in labs
- Live animal hosts,
- Embryonated eggs,
- Cell Cultures
Describe structure of COVID virus
Enveloped, single strand RNA, protein helical capsid
Caliciviruses charachteristics
NOT enveloped, Norovirus, icosahedral, ssRNA
Calicivirus diseases
Gastroenteritis, outrbreaks in care homes and cruise ships
Transmission of Caliciviruses
Fecal-oral
Pathogenesis of Caliciviruses
Relicate in small intestine epithelium, mucosal damage, loose digestive enzymes
Herpesvirus charachteristics
dsDNA, enveloped, icosahedral
Herpes transmission
Saliva, semen
Coronaviruses charachteristics
ssRNA or dsRNA, spherical, helical, enveloped
Retroviruses charachteristics
dsRNA, ssRNA, enveloped, icosahedral, truncated cone shape
Diseases associated with retrovirus
HIV, HTLV 1/2
Transmission of retroviruses
Musal route infection with CD4-positive cells, spread through body including CNS
