BIO205 Viruses and Viral Diseases

Virus

Acellular, nonliving, intracellular parasite

Size of virus

20-250 nm

Three basic shapes of virus

Helical, polyhedral, and complex

Extracellular state

Virus that is completely assembled that exist outside of host; they cannot reproduce

Intracellular state

Virus that exists inside the host as a nucleic acid; it takes up the hosts DNA too

Enveloped virus

Have an outer lipid membrane

Naked virus

Lack an outer membrane

Where virus envelope is derived from

The host’s cell membrane

Outermost layer function

Genetic material in viruses

Viral genome

Classification of viruses

1. Nucleic acid type

2. Presence or absence of enveloped

5 stages of lytic replication

1. Attachment

2. Entry

3. Synthesis

4. Assembly

5. Release

Lytic replication

Replication of virus that usually ends in the death of host

3 methods of virus entry in host cell

DNA virus location

Host’s nucleus

RNA virus location

Host’s cytoplasm

Molecule needed in animal viruses for synthesis

DNA or RNA

Budding

Process of enveloped viruses exiting host cell

Viral latency

Virus remaining inactive

Provirus

DNA that has integrated into the host cell’s genome

Virion

Virus in the Extracellular state

Capsid

Protein code that surrounds the nucleic acid (virus genome)

Capsomere

Protein unit that make up capsid

Nucleocapsid

Combination of nucleic acid and capsid

Enveloped virus

Phospholipid bilayer that surrounds virus and coats it

Naked virus

No outer coat/shell

Uncoating

Process of virus removing its capsid

Glycoproteins

Proteins that have sugar molecules attached

Spikes

Viruses that have proteins that are virally-coded glycoproteins

Bacteriophage

Virus that infects bacteria

Prophage

Virus that has integrated the bacterial host cell’s genome

Induction

When dormant Prophage is activated

Budding

Enveloped viruses exit host cell

Latency

State of virus remaining dormant within host cell

Provirus

DNA that has integrated the genome of a host cell