Test 3 - Viruses: General Introduction Flashcards
Viruses DO have
Genetic material surrounded by protein
Viruses DO NOT have
PM, organelles, or ribosomes
Living or Not: Is the Virus organized?
Yes.
Living or Not: Is this Virus able to Metabolize? Why?
Metabolic Activity/E do not exist outside the host because it lacks structure for metabolism, and uses host structures instead.
Living or Not: Is the Virus able to grow/develop?
No.
Living or Not: Does the virus reproduce?
Yes, in the host.
Living or Not: Is the virus able to interact and respond to the environment? Examples (2)?
Yes.
- Viruses can ∆ gene expression depending on the environment.
- Viruses must interact with cell surface to trigger infection.
Living or Not: Is the virus able to Evolve?
Yes.
Living or Not: Is the virus living?
No. Virus has property of life, but cannot reproduce/metabolize by itself, and hence is not life.
Viral Genome is different than Cellular Genome because…
It can be both RNA and DNA based. (Cells do not have RNA genome.)
Viral genome has 3 characteristics…
- DNA or RNA
- x1 or x2 stranded
- Linear or Circular?
Viral genome codes for 3 functions:
- Structure
- Reproduction
- Entry and Exit from Host
What is a Capsid? Is it present in all viruses? What is its subunit called?
Protein surrounding genome, present in all viruses, made of subunits named capsomere.
What is a Viral Envelope? Is it present in all viruses? What is it made of? How is it advantageous?
Membrane-like structure that surrounds the CAPSID, present in only some viruses. It is made up of viral proteins and host proteins, which aids in infection.
How does the Virus infect Host Cells? (6 Steps)
- Viral coat protein (capsid or viral envelope) binds to host cell receptor with high specificity.
- Virus enters cell
- Virus is uncoated (no more capsid/envelope)
- Virus is replicated. (Both genome and protein).
- Newly made genome and capsid assemble into virion through spontaneous reaction due to existing affinities.
- Virion is released from host cell.