Chapter 9 - Viruses

Virus

An infectious particle consisting of genes packaged in a protein coat.

Living or Nonliving

Most virologists agree that viruses are not alive but lead 'a kind of borrowed life'.

DNA virus

A virus that has DNA as its genetic material.

RNA virus

A virus that has RNA as its genetic material.

Capsid

The protein shell enclosing the viral genome.

Host range

The limited range of host cells that a virus can infect.

Lytic cycle

A viral replicative cycle that culminates in the death of the host cell.

Lysogenic cycle

A viral replicative cycle where the virus's genome replicates without destroying the host cell.

Retrovirus

A virus that transcribes DNA from an RNA template, characterized by the presence of reverse transcriptase.

Prion

Infectious proteins that can cause degenerative brain diseases.

Viral genome

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

Envelope

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

Viral replication

The process by which a virus makes copies of itself within a host cell.

Antiviral drugs

Medications used to treat viral infections by inhibiting the development or replication of viruses.

Pathogen

An organism, such as a virus, that causes disease in a host.

Zoonosis

The transmission of viruses from animals to humans.

Vaccine

A biological preparation that provides active acquired immunity to a particular viral infection.

Asymptomatic

A stage in which an infected individual shows no symptoms of illness.

Mutation

A change in the viral genome that can lead to variations in virus properties.

Host cell

The living cell in which a virus replicates.