Chapter 13: Viruses, Viroids, & Prions

These flashcards cover key concepts, vocabulary, and definitions related to viruses, viroids, and prions as discussed in Chapter 13 of the lecture notes.

Virion

Complete, fully developed infectious viral particle.

Capsid

Protective protein coat surrounding the viral nucleic acid.

Nucleic acid

The genetic material of the virus, which can be DNA or RNA.

Host range

The specific types of cells or organisms that a virus can infect.

Generalists

Viruses that can infect many types of cells across different hosts.

Bacteriophage

A virus that specifically infects bacteria.

Capsomeres

The protein subunits that make up the capsid.

Envelope

A lipid, protein, and/or carbohydrate layer around some capsids.

Spikes

Protein-carbohydrate complexes used for attachment to host cells.

Polyhedral viruses

Viruses with many sides, with the icosahedron being the most common form.

Helical viruses

Viruses that are shaped like long rods or cylinders.

Complex viruses

Viruses with complicated structures that exhibit both helical and polyhedral characteristics.

Lytic cycle

A phase in viral replication where infected cells are lysed and destroyed.

Lysogenic cycle

A phase in viral replication where the phage DNA incorporates into the host genome and remains dormant.

Prophage

The dormant form of a phage when it integrates into the host chromosome.

Transduction

The process by which DNA is transferred from one bacterium to another by a virus.

Endocytosis

The process by which viruses enter host cells by engulfing them.

Budding

The process by which enveloped viruses are released from host cells.

Exocytosis

The process by which naked viruses are released from host cells.

Latent viral infections

Infections where the virus remains dormant in the host cell for long periods.

Cytopathic effects

Observable changes in host cells caused by viral infections.

Serological tests

Tests that detect antibodies against viruses in a patient.

RFLPs

Restriction fragment length polymorphisms, a method for analyzing DNA.

PCR

Polymerase chain reaction, a technique used to amplify DNA sequences.

Cultivation of viruses

The process of growing viruses in living cells

different techniques are required to grow and maintain viruses

techniques used depend on the normal host of the virus.

Animal viruses

Viruses that infect animal cells, often requiring different techniques for cultivation.

Embryonated eggs

Eggs used as a medium for growing animal viruses.

Cell culture

A method for growing viruses in isolated cells from an organism.

Taxonomy of viruses

The classification of viruses based on nucleic acid type, replication strategy, and morphology.

Viridae

The suffix used for naming virus families.

Virus genus

The category in virus classification that groups viruses with similar characteristics.

Prions

Infectious protein particles that cause neurological diseases.

Protein is an altered normal cellular protein

Inherited and transmitted by ingestion, transplant, and surgical instruments.

Spongiform encephalopathies

A group of neurodegenerative disorders associated with prions.

Creutzfeldt-Jakob disease

A human prion disease characterized by rapid neurodegeneration.

Mink encephalopathy

A prion disease affecting minks.

Bovine spongiform encephalopathy

A prion disease in cattle, also known as mad cow disease.

Fatal Familial Insomnia

A prion disease characterized by severe sleep disturbances.

Gertrudam-Straussler-Scheinker syndrome

A rare genetic prion disease characterized by ataxia.

Kuru

A prion disease observed in humans, historically linked to cannibalism.

Alpers Syndrome

A prion disease that affects infants, causing neurological dysfunction.

Oncogenic viruses

Viruses that can cause cancer in the host organism.

Zoonotic viruses

Viruses that are transmitted from animals to humans.

Immunoglobulin

Antibodies produced by the immune system to identify and neutralize pathogens.

Viral hemagglutination

A test that determines the ability of viruses to agglutinate red blood cells.

Cultivation of bacteriophages

Grown in either liquid cultures of bacteria, or in bacterial cultures on solid medium

Viruses can be detected by the formation of plaques

Cultivation of Animal Viruses

Animal viruses may be grown in living animals, embryonated eggs, or in cell culture

Observers see cytopathic effect-cell deterioration due to virus activity

Viral replication in the lytic cycle

Virus comes into cell, makes all viral products it needs, puts all viral products back together, then releases through host cell

Lysogenic cycle Viral replication

Replicates viral DNA but doesn’t cause cells to be destroyed, incorporated into genetic material and causes infection in lytic cycle

Replication of animal viruses process

Viruses attach to cell membrane, penetration by fusion, uncoats itself, makes viral products, puts them back together, then released and destroys host cells

Requirements for Replication of animal viruses

Requires different strategy depending on its nucleic acid

DNA viruses assemble in nucleus and RNA viruses develop solely in cytoplasm

Number of viruses depend on on type of virus and size and initial health of host cell

Enveloped viruses cause persistent infections

Naked viruses are released by exocytosis or lysis

3 ways animal viruses come in body

Endocytosis, membrane fusion, direct penetration which is the rarest

Enveloped viruses

Surrounded by an envelope roughly spherical

Can be helical or polyhedral

Viral species

A group of viruses sharing the same genetic information and ecological host.