What are viruses? Flashcards
Importance of Koch and Pasteur in virology
Developed porcelain-based filter
Contaminated liquids that passed through = no longer infectious
Viruses could pass through - turning point for virology
Importance of Dmitri Ivanovski in virology
Investigates the tobacco mosaic virus
Infected leaves had patched appearance - light sections = dead
Mashed infected leaves into extract and ran through filter
Still caused disease -> transmissable entity could not be filtered away
Importance of Martinus Beijerinck in virology
Investigated tobacco mosaic virus
Agent causing disease could only multiply on living plants
So replicating agent = not a toxin
Thought it was a poisonous living fluid
Came up with name virus
Importance of Loeffler and Frosch in virology
Same filter observation
But with human virus
Foot and mouth virus
Importance of Walter Reed in virology
Described the yellow fever virus
Was the first human virus
What are the 3 basic characteristics of viruses?
Small - can be filtered
Dependent on host - different from all other organisms
Transmissible - key to viral survival
What is the importance of transmission in viruses?
Key to viral survival
Everything about virus biology is focused on securing transmission to a new host
What is another way of describing viruses?
By what they don’t do compared to other biological entities
What do viruses not do compared to other biological entities?
Grow
Respond to stimuli
Consume energy
Undertake homeostasis - same environment inside as outside the virus
Reproduce
What happens to viruses without a host?
Becomes inert
No biological characteristics
Average size of viruses?
20 - 300 nm
What are the two key components of viruses needed for them to transmit from one host to another?
Genome
Container for the genome
What is a viral genome?
Encodes information to direct the host cell to generate new viruses
Can be made of DNA or RNA
What is the container of a viral genome?
Necessary to get the genome from one host to another
Called capsid - protein shell that protects the genome
What is a capsid?
Container for viral genome
Made of protein