Virus Basics
What theory explains how mitochondria and chloroplasts originated from engulfed bacteria?
Endosymbiotic theory
What type of microscope do you need to see viruses?
Electron microscope
Transfer of genes from parent to offspring is called what?
Vertical gene transfer
The protein shell that protects viral nucleic acid is called what?
Capsid
Where do most DNA viruses replicate?
Nucleus
Are viruses considered living or nonliving, and why?
Nonliving; no metabolism, cannot replicate on its own
Which scientist used porcelain filters to study tobacco plant disease?
Dmitri Ivanovsky
What is it called when DNA moves between species?
Horizontal gene transfer
What do we call the viral genome + capsid together?
Nucleocapsid
Why do RNA viruses mutate faster than DNA viruses?
RNA polymerase lacks proofreading, RNA unstable
What is a virus made of at minimum?
Nucleic acid + protein
The fact that viruses passed through Chamberland filters showed what about their size?
Smaller than bacteria
Diseases that jump from animals to humans are called what?
Zoonotic
Give one advantage of a viral envelope.
Hides from immune system
Which type of RNA virus can go straight to the ribosome to make proteins?
+ssRNA
What determines which cells and species a virus can infect, and why is this important for viral replication?
viruses require specific receptors on host cells to enter and replicate, which limits which species or tissues they can infect.
Early scientists first thought the infectious agent in tobacco plants was what?
Thought to be a toxin
Example of vertical gene transfer in humans (make one up)?
Having a child → child → grandchild
Name two capsid shapes.
Anyone from helical, icosahedral, complex, or enveloped
Which RNA viruses need to make a complementary strand before translation?
–ssRNA
How does the endosymbiotic theory relate to eukaryotic cell development?
Eukaryotic cells evolved by engulfing prokaryotes → mitochondria/chloroplasts
Why was the discovery of reverse transcriptase so significant?
Reverse transcriptase allowed RNA → DNA, (amazing for study of differential gene expression)
Why do we often need new vaccines for RNA viruses like influenza?
RNA viruses mutate fast so need new vaccines
Give one example each of a helical, icosahedral, enveloped, and complex virus.
Helical: Ebola
Icosahedral: Adenovirus
Enveloped: Herpes
Complex: T4 phage
What enzyme do retroviruses use to convert RNA → DNA?
Reverse transcriptase