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Virus

A virus is an obligate intracellular parasite that requires living host cells to multiply.

Obligatory intracellular parasites

Organisms, such as viruses, that must enter living host cells to reproduce.

Capsid

The protein coat that encases the genetic material of a virus.

Envelope

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

Bacteriophage

A virus that infects bacteria.

Lytic cycle

A process in which a phage infects a bacterium, replicates, and causes the host cell to lyse (burst), releasing new phages.

Lysogenic cycle

A process in which the viral DNA integrates into the host cell's chromosome and can remain dormant before entering the lytic cycle.

Prophage

The form of a virus that has integrated into the host's DNA during the lysogenic cycle.

Oncogene

A gene that has the potential to cause cancer when mutated or expressed at high levels.

Persistent viral infection

A viral infection that occurs slowly over time and is generally fatal.

Latent viral infection

A viral infection that remains dormant in the host for long periods and may reactivate.

Plant viruses

Viruses that infect plant cells, often transmitted through wounds or by insects.

Viroid

A small infectious RNA particle that causes disease in plants.

Serological tests (ELISA)

A lab test used to detect the presence of antibodies or antigens, often used for viral identification.

Reverse transcriptase

An enzyme used by retroviruses to synthesize DNA from their RNA genome.

Viral species

A group of viruses that share the same genetic information and ecological niche, classified under a common name.

Bacteriophage Replication involves

injection of naked nucleic acid into the host cell

Nucleic acid, number of capsomers, morphology and size

key characteristics used to classify viruses.

viral spikes

protein structures on the surface of viruses that facilitate attachment to host cells.

plaque

a clear zone formed on a bacterial lawn due to the lysis of bacteria by a virus.

retrovirus

a type of virus that replicates its RNA genome by reverse transcription into DNA, which integrates into the host genome.

how are bacteriophages cultured?

Bacteriophages are cultured by infecting a bacterial host in a liquid culture or on a solid agar plate, allowing the phages to reproduce and form plaques.

How are animal viruses cultured?

Animal viruses are cultured in living host cells, such as embryonated eggs or cell cultures, where they can replicate and produce infectious particles.

three techniques used to identify viruses

Serology, electron microscopy, and molecular methods.

First step of a virus with a minus strand of RNA

is to enter the host cell and release its RNA genome into the cytoplasm.