Lecture_11_and_12_Viruses___Eukaryotes__-__UPDATED

Virus

A genetic element that cannot replicate independently of a living (host) cell.

Viral particle

Extracellular form of a virus; allows virus to exist outside host and facilitates transmission.

Virion

The infectious virus particle; contains nucleic acid genome, protein coat, and potentially other materials.

Capsid

The protein shell that surrounds the genome of a virus particle.

Capsomer

A subunit of the capsid.

Nucleocapsid

The complete complex of nucleic acid and protein packaged in the virion.

Enveloped virus

A virus that contains additional layers around the nucleocapsid.

Helical symmetry

A structural arrangement of virions; rod-shaped viruses.

Icosahedral symmetry

A structural arrangement of virions; spherical viruses.

Titer

The number of infectious units per volume of fluid.

Plaque assay

A method to measure virus infectivity, where clear zones develop on lawns of host cells.

Lytic cycle

A virulent mode where viruses lyse host cells after infection.

Temperate mode

A viral life cycle where viruses replicate their genomes in tandem with host genome without killing the host.

Lysogeny

A state where most virus genes are not expressed and virus genome is replicated with the host chromosome.

Retroviruses

RNA viruses that replicate via a DNA intermediate, containing reverse transcriptase.

Prion

An infectious protein known to cause transmissible spongiform encephalopathies in animals.

Nucleotide

A basic building block of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base.

RNA-dependent RNA polymerase

An enzyme required by negative-strand RNA and double-stranded RNA viruses to make mRNA.

Concatenation

A feature of many virus genomes where the same genes are arranged in different orders.

Terminal redundancy

Some DNA sequences in virions are duplicated on both ends.

Attachment (adsorption)

The phase of viral replication where the virus attaches to a susceptible host cell.

Entry (penetration)

The phase of viral replication where the virion or its nucleic acid enters the host cell.

Eclipse

The phase of viral replication where the genome is replicated and proteins are translated.

Maturation

The phase of viral replication where capsids are assembled and viral genomes are packaged into new virions.

Release

The phase of viral replication characterized by the lysis of the host cell and release of new virions.

Positive-strand RNA virus

A virus with single-stranded RNA genome that has the same orientation as its mRNA.

Negative-strand RNA virus

A virus with single-stranded RNA genome that has a complementary orientation to its mRNA.

Apicomplexans

Obligate parasites of animals that contain apicoplasts, which are degenerated chloroplasts.

Eukaryotes

Organisms that contain a membrane-enclosed nucleus and several organelles.

Mitochondrion

An organelle that serves in respiration and oxidative phosphorylation.

Hydrogenosome

An organelle that lacks citric acid cycle enzymes and is involved in anaerobic metabolism.

Chloroplast

A chlorophyll-containing organelle found in phototrophic eukaryotes.

Stramenopiles

A group that includes oomycetes, diatoms, and brown algae.

Ciliates

A group of alveolates that possess cilia at some stage of their life cycle.

Dinoflagellates

Diverse marine and freshwater phototrophic organisms, some of which cause harmful algal blooms.

Bacteriophage T4

A well-studied bacteriophage with complex penetration mechanisms and distinct life cycles.

Influenza virus

An enveloped virus known for causing flu infections.

Viroid

A small infectious RNA that does not encode proteins and causes diseases in plants.

Genome packaging

The process of filling the virus head with viral DNA under pressure.

E. coli

A commonly studied bacterial host for bacteriophage infections.

Quorum sensing

A communication process that enables bacteria to monitor their population density.

CRISPR

A defense mechanism that bacteria employ against viral infections.

Bacteriophage

A virus that specifically infects bacteria.

Lysogenic pathway

A viral replication pathway where the viral genome integrates into the host genome.

Bacterial cell envelope

The protective layer surrounding bacterial cells, targeted by some viruses during infection.

Epidemiology

The study of how diseases spread and can be controlled in populations.

Transformation

The process by which a virus converts a normal cell into a tumor cell.

Persistent infection

A state where infected cells continuously produce virus without cell lysis.

Latent infection

A delay between infection and the lytic events of a virus.

Filamentous growth

A growth pattern seen in some fungi, characterized by hyphae.

Mycelium

A compact tuft formed by the growth of fungal hyphae.

Conidia

Asexual spores produced by some fungi.

Basidiospores

Reproductive spores produced by mushrooms.

Mycorrhizae

Symbiotic associations between fungi and plant roots that help in nutrient absorption.