Viruses

These flashcards cover key terms and definitions related to viruses, their structures, classifications, infections, vaccines, and antiviral drugs.

Virus

Acellular, parasitic entities that require a host cell for replication and do not have a cellular structure.

Capsid

A protein shell that surrounds and protects the genetic material of a virus.

Nucleic Acid

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

Progressive Hypothesis

Proposes that viruses originated from RNA and DNA molecules that escaped from a host cell.

Regressive Hypothesis

Suggests that viruses evolved from free-living cells or intracellular parasites that lost their cellular components.

Virus-First Hypothesis

Suggests that viruses may have been the first self-replicating entities before the first cells.

Enveloped Virus

A virus that has an additional outer lipid layer derived from the host cell’s membrane.

Viral Infection Stages

The process of viral infection includes attachment, penetration, replication, assembly, and release.

Acute Infection

A type of viral infection that causes rapid onset symptoms for a short duration.

Chronic Infection

An infection that persists over a long period, with symptoms that may fluctuate.

Inactivated Vaccines

Vaccines that use a killed version of the virus and typically require multiple doses.

Live Attenuated Vaccines

Vaccines that use a weakened form of the live virus, usually requiring fewer doses and providing a strong immune response.

mRNA Vaccines

Vaccines that use mRNA to instruct cells to produce a specific viral protein to trigger an immune response.

Antiviral Drugs

Medications that inhibit viral proteins without damaging the host cell.

Viral Latency

A state in which a virus remains dormant in a host's cells without causing immediate symptoms.

Lysogeny

The process where certain viruses, like bacteriophages, integrate their DNA into the host cell's genome and remain inactive.