Non-Living Particles-Viruses, Virions, and Prions

Rickettsia/Chlamydia

Intracellular Parasite

Plasma membrane

Binary Fission

DNA and RNA

Ribosomes

Sensitive to Antibiotics

Distinctive characteristics of viruses

either DNA or RNA, never both

protein coat

intracellular parasite

synthesis of specialized structures for transference

Host Range

the spectrum of host cells the virus can infect

Virion

complete, fully developed infectious and inactive particles composed of nucleic acid, surrounded by a protein coat outside the host cell (extracellular)

Virus

microscopic active structures that can replicate only inside a host cell after high-jacking host cell structures

Nucleic Acids

DNA or RNA, never both

single-stranded or double-stranded

linear, circular, or segmented

Capsomeres

subunits of protein that make up the capsid

Capsid

viral protein coat that protects the viral nucleic acid

Virus Envelope

composed of lipids, proteins and carbohydrates

Enveloped viruses

acquired during the release of animal viruses

Spikes

carbohydrate-protein complexes that project out for viral attachment

Non-enveloped capsids

protect nucleic acids from nucleases

Helical Viruses

long rods that may be rigid or flexible

nucleic acid is in a hollow, cylindrical capsid

Rabies and Ebola

Polyhedral viruses

many-sided virus

icosahedron capsid

Complex viruses

bacteriophages

Enveloped viruses

roughly spherical

helical and polyhedral can be enveloped

Eclipse period

complete and infective virions are not yet present

How many virions are produced by one virion during multiplication?

thousands

Uncoating Stage

the separation of the viral nucleic acid from its protein coat

Viroids

short pieces of naked single-stranded RNA

Virusoids

viroid that may be enclosed in a protein coat and require other helper viruses to establish an infection

Prion

normal host glycoprotein called PrPc becomes infectious PrPsc

What major animal tissue is afflicted by prions?

Brain

Bacteriophages

virus that infects bacteria

useful tool in labs

lytic cycle

What is the outcome of the lytic cycle?

death of the infected cell

What is the difference between the Lytic Cycle and the Lysogenic Cycle?

The lysogenic cycle is latent for a long time before the cell dies