Viruses, Viroids, and Prions

Flashcards created based on microbiology notes focusing on viruses, viroids, and prions, covering definitions, concepts, and processes.

Virus

An obligatory intracellular parasite that can infect all forms of life, containing DNA or RNA and a protein coat.

Viroid

A small infectious agent composed solely of naked RNA, known to cause diseases in plants.

Prion

A proteinaceous infectious particle that causes neurodegenerative diseases by inducing abnormal folding of normal proteins.

Lytic Cycle

A method of viral replication where the virus attaches, penetrates the host, synthesizes its components, assembles them, and then causes the host cell to lyse, releasing new virions.

Lysogenic Cycle

A viral replication cycle where the viral genome integrates into the host genomic DNA and replicates along with it without causing immediate cell death.

Capsid

The protein coat surrounding a virus, composed of subunits called capsomeres.

Envelope

An outer lipid membrane that surrounds some viruses, derived from the host cell membrane.

Bacteriophage

A type of virus that specifically infects bacteria, attaching to the bacterial cells and utilizing their machinery for replication.

Oncogene

A gene that has the potential to cause cancer, often activated or transferred by viral infections.

Antisense RNA

A strand of RNA that is complementary to a sense strand of RNA; it must be transcribed into the sense strand before viral proteins can be synthesized.

Serological tests

Diagnostic tests that detect antibodies against specific viruses in a patient’s serum to identify viral infections.

Transduction

The process by which foreign DNA is introduced into a cell by a virus, leading to genetic variation.

Nucleic acid

The genetic material of a virus, which can be either DNA or RNA, and may be single-stranded or double-stranded.

Spikes

Surface proteins on the envelope of some viruses that help in attachment to host cells.

Immune-mediated lysis

Cell death caused by the immune system as it responds to viral infections.

Reverse transcriptase

An enzyme used by retroviruses to transcribe their RNA genome into DNA.

Provirus

The viral DNA that integrates into the host cell’s genome during the lysogenic cycle.

Acute infection

A rapid onset of infectious disease, typically characterized by a sudden appearance of symptoms and a quick resolution.

Chronic infection

A long-lasting viral infection that may remain in the body for years, often with periods of active disease.

PCR (Polymerase Chain Reaction)

A laboratory technique used to amplify DNA, enabling the detection and analysis of viral DNA.

HIV

Human Immunodeficiency Virus, a retrovirus that attacks the immune system, leading to AIDS.