Viruses, Viroids, and Prions

These flashcards cover essential vocabulary related to viruses, viroids, and prions as discussed in the lecture.

Virus

Genetic element (DNA or RNA) that can only replicate inside a living cell (host cell).

Virion

The infectious virus particle.

Obligate intracellular parasite

Organisms that can only replicate inside a living host cell.

Acellular

Organisms or entities that lack cellular structure.

Host range

The spectrum of host cells a virus can infect.

Genome

The complete set of genetic material (DNA or RNA) in a virus.

Capsid

The protein coat of a virus that encases the nucleic acid.

Envelope

A lipid membrane that surrounds some viruses, derived from the host cell's membrane.

Nucleocapsid

The combination of a virus's nucleic acid and its protein coat (capsid).

Matrix proteins

Proteins associated with the viral envelope, important for virion structure.

Accessory proteins

Proteins carried by some viruses that assist in infection and replication.

Lysis

The breaking down of the cell membrane, leading to the release of new virions.

Budding

The process by which enveloped viruses exit the host cell without killing it.

Plaque assay

Method used to estimate the number of infectious virions in a sample.

Titer

The concentration of infectious virions in a given volume of fluid.

Hemagglutination

The clumping of red blood cells caused by viral proteins.

Eclipse period

The phase in viral replication where no infectious virus can be detected.

Provirus

Viral DNA integrated into the host cell's genome.

Viroid

A small, infectious RNA molecule that lacks a protein coat, primarily infects plants.

Prion

An infectious agent composed entirely of protein, leading to neurodegenerative diseases.

Inclusion bodies

Intracellular aggregates of viruses or damaged organelles.

Latent period

The time during viral infection from entry to the release of new virions.

Virus replication cycle

The series of stages a virus goes through to replicate within a host cell.

Early proteins

Proteins synthesized soon after viral infection that aid in virus replication.

Late proteins

Structural proteins required for the assembly of new virions.

Transmissible spongiform encephalopathies

Neurodegenerative diseases caused by prions, leading to sponge-like brain tissue.

Nucleic acid amplification test (PCR)

A molecular method used to amplify and detect viral DNA or RNA.

Antibody testing

Tests that detect antibodies produced in response to viral infections.

Enzyme-Linked Immunosorbent Assay (ELISA)

A serological test used to detect viral particles or antibodies in a sample.

Gene transfer

The process by which viruses can facilitate the transfer of genetic material between organisms.

Symbiosis

A relationship between two organisms where both benefit from each other.

Carbon cycle

The process by which carbon is exchanged between the atmosphere, land, and oceans.

Nutrient recycling

The process of reusing nutrients from dead organisms, facilitated by viruses.

Viral shunt

A process in aquatic environments where viruses help recycle nutrients by selectively killing phytoplankton.

Size of Viruses

Viruses typically range from 20 nm to 450 nm in diameter.

Bacteriophage

A virus that infects bacteria.

Serological tests

Tests that use antibodies to detect viral particles or immune responses.

Cytopathic effects

Visible symptoms of viral infection in host cells.

Bovine spongiform encephalopathy

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

Creutzfeldt-Jakob disease

A prion disease in humans causing rapid neurodegeneration.

RNA replicase

An enzyme that replicates RNA; essential for some RNA viruses.

Reverse transcriptase

An enzyme used by retroviruses to synthesize DNA from RNA.

Matrix proteins

Proteins that play a crucial role in the morphology of the virion.

RNA-dependent RNA polymerase

An enzyme crucial for the replication of RNA viruses.

Spike proteins

Viral proteins that project from the envelope and facilitate host cell entry.

Icosahdron

A polyhedral shape with 20 faces, common among many viruses.

Replication cycle phases

The stages of viral infection: attachment, penetration, synthesis, assembly, and release.