Chapter 5 and 11 pt 3 Flashcards
What type of genome do Retroviruses have?
Single-stranded RNA (two copies per virus)
What enzyme do Retroviruses use to make DNA from RNA?
Reverse transcriptase
What does Retroviridae do with the DNA it makes?
ntegrates it into the host genome
Which Retrovirus genus includes HIV?
Lentivirus
What kind of diseases can Oncogenic Retroviruses cause?
Cancer (they are RNA tumor viruses)
What is antigenic shift in influenza viruses?
A major genetic reassortment that leads to new virus subtypes and pandemics.
What causes genetic reassortment in influenza viruses?
Exchange of gene segments when two different strains infect the same cell
What is antigenic drift?
Gradual mutations in the hemagglutinin (HA) and neuraminidase (NA) genes.
Which viral proteins are affected by antigenic drift?
Hemagglutinin (HA) and Neuraminidase (NA)
Which influenza process is responsible for seasonal flu variation?
Antigenic drift
What are prions made of?
Protein only—no nucleic acid (DNA or RNA)
How can prion diseases be transmitted?
Inherited, ingestion, transplants, and contaminated surgical instruments
What diseases are caused by prions?
Scrapie (sheep), Creutzfeldt-Jakob disease, mad cow disease (BSE), chronic wasting disease
What is the normal prion protein called?
PrPC – found on healthy cell surfaces
What is PrPSc and what does it do?
Misfolded prion protein that accumulates in brain cells and forms plaques
How do plant viruses typically enter plants?
Through wounds or via insect vectors
What are viroids made of?
Infectious RNA with no protein coat
Do viroids encode proteins?
No, they do not encode any proteins
What is the smallest known pathogen?
Viroids
Give an example of a disease caused by a viroid.
Potato spindle tuber disease
