Virology Flashcards
Virology
Study of viruses and viral disease
Virologist
Someone who studies viruses, they are important because viral diseases can cause high rates of mortality and morbidity in animals and birds
Why are virologist important?
- Can significantly impact food safety and security
- Can cause tremendous economic losses and are expensive to control and prevent
Zoonosis: Viral disease can be transmitted from animals to humans
Defining Viruses
- viruses are non-living entities.
- contain DNA or RNA surrounded by a protein coat (capsid) and, in some cases, other layers of material, such as a lipid envelope.
- Viruses do not possess standard cellular organelles such as mitochondria, chloroplasts, Golgi, and endoplasmic reticulum with associated ribosomes.
- Viruses cannot make energy or proteins by themselves and have to rely on a host cell.
- All Viruses are like obligate intracellular parasites. Outside the living cell, viruses are inert or dormant particles, whereas, inside the cell, the virus hijacks and utilizes the host cell machinery to produce its proteins and nucleic acid for the next generation of virus. Viruses cannot make energy or proteins by themselves and have to rely on a host cell.
- Viruses such as Binary Fission do not have the genetic capability to multiply by division. The process of Virus reproduction resembles an assembly line in which various parts of the virus come together from different parts of the host cell to form new virus particles.
Structure of viruses
DNA and RNA genes
Capsid
Envelope, a bubble of fat
Molecular protein
What is a capsid?
A protein shell of a virus that encases/envelopes the viral nucleic acid or genome
What are capsids made of?
Capsomeres held together by covalent bonds
Nucleocapsid
Capsid + Virus Nucleic acid (DNA or RNA)/Genome
What is the additional layer that some viruses have
Lipid envelop
What is the lipid envelope?
Some Viruses may have an additional layer known as an envelope that covers the capsid.
The envelope is usually a lipid bilayer derived from the host cell.
Glycoproteins are present on the envelope’s surface, often appearing as spikes.
Naked virus
Only protein capsid enclosing nucleic acid
Enveloped viruses
additional layer enclosing the protein capsid enclosing the nucleic acid
Pleomorphism
ability of some virus to alter shape and size
Virus replication
Attachment to the cell
penetration and uncoating: to the cell membrane and injects DNA or RNA into the cell
synthesis of viral nucleic acid and protein replication using cell host machinery
assembly and maturation; release in lg # viral nuclei acid are packaging into viral particles and release from the cell; the host may be destroyed in the process
Impacts of virus replication in host cell
Cell death: Lysis, Alteration Cell Membrane, Apoptosis (Cell Suicide)
No apparent changes to the infected cell. Latent, Persistent or Chronic infection
Fusion of cells: Multi nucleated
Transformation of cell to malignant one
