Viruses

Are viruses cellular?

no

1 multiple choice option

Bacteria is a ___ and fungi is a ___ .

prokaryote, eukaryote

1 multiple choice option

Ivanovski and Beijerinck

showed that a tobacco disease was caused by a virus

Loeffler and Frisch

discovered an animal virus that causes food and mouth disease in cattle

Walter Reed

showed yellow fever is caused by a virus carried by mosquitoes

5 main properties of viruses

subcellular, parastic, pathogens, contain a nucleic acid, and protein coat

What does negative staining do?

shows outlines of the small virus

What does positive staining do?

shows internal viral details

Shadow casting technique

a heavy metal is evaporated at a specific angle to the specimen that accumulates to form a shadow

Crystallography

determines the structure of a specimen by studying the interference patterns produced by waves passing through a crystal of the specimen

Viral molecular structure

composed of regular, repeating subunits that give rise to their crystalline appearance

Viral Components for hos invasion

capsid protein coat, envelope, and a genome (DNA/RNA)

External Viral Structure

capsid protein coat and a envelope found in 13/20 animal viruses

Core Viral Structure

DNA/RNA

Nucleocapsid

the capsid and the nucleic acid together

Virion

a fully formed virus that is able to establish an infection in a host cell

How do enveloped viruses form their envelope?

taking a piece of the host cell membrane and replacing most components to viral

Some proteins form what between the envelope and capsid?

binding layer

Role of Viral capsid or envelope

protect genetic material, help introduce viral material into a host cell, and stimulate the immune system to produce antibodies that protect the host cell

Parvoviruses

small, naked, ssDNA viruses

Reoviruses

naked dsRNA viruses

Which DNA virus type can be either ds or ss

nonenveloped

Enveloped DNA viruses of Eukaryotes

ds genome that gives rise to poxviruses and herpesviruses

Non-enveloped viruses of Eukaryotes

ds genome that gives rise to adenovirus (linear dsDNA) and papovavirus (circular dsDNA) or ss genome that gives rise to parvoviruses

Positive-sense RNA

genomes that are ready for immediate translation into proteins

Negative-sense RNA

genomes that have to be converted to the proper form to be made into proteins (RNA -> cDNA)

Segmented genome

individual genes exist on separate RNA pieces

Multiplication cycles in animal viruses

adsorption (attachment), penetration (viral entry), uncoating (viral release), synthesis (viral products made), assembly (viruses made), release (causes lysis of host cell busrsting 100,000 virons)

What stage of the multiplication viral cycle is endocytosis occurring and why

penetration due to the entire viruses being engulfed and enclosed in a vesicle

DNA/RNA synthesis can occur in the ____ but protin synthesis occurs in the ___ only.

cytoplasm or nucleus, cytoplasm

Enveloped viruses are liberated by...

budding or exocytosis

Cytopathic effects

virus-induced damage to the cell that alters its microscopic appearance

Inclusion bodies

compacted masses of viruses/damaged cell organelles

Synctia (Host cell damage)

fusion of multiple host cells into single large cells containing multiple nuclei

Transformation (Host cell damage)

oncogenic, cancer causing oncoviruses

Noncellular infectious agents

deltavirus hepatitis delta and prions proteinaceous infectious particles