Viruses, Viroids, and Prions

Flashcards covering key concepts of viruses, the immune response, and metabolism.

Virus

An infectious particle made of nucleic acid (DNA or RNA) and a protein coat (capsid) that cannot replicate on its own.

Capsid

The protein shell of a virus made of subunits called capsomeres.

Nucleocapsid

The combination of the capsid and the nucleic acid of a virus.

Enveloped Virus

A virus that has a lipid layer from host cells with embedded spikes; less resistant to disinfectants.

Naked Virus

A virus without an envelope; more resistant to harsh conditions.

Icosahedral

A shape of a virus characterized by 20 sides.

Lytic Phages

Phages that always kill the host cell by going through a lytic cycle.

Temperate Phages

Phages that can choose between a lytic cycle and a lysogenic cycle.

Generalized Transduction

The process by which a phage mistakenly packages host DNA during assembly, allowing any gene to be transferred.

Lysogenic Cycle

When phage DNA integrates into the host genome to form a prophage; most prophage genes are silent.

RNA Viruses

Viruses that use replicase for synthesis and lack proofreading, leading to mutations.

Retroviruses

RNA viruses that reverse transcribe their RNA into DNA using reverse transcriptase.

Prions

Infectious proteins that cause neurodegenerative diseases and are resistant to heat and disinfectants.

First-Line Defenses

Physical and chemical barriers that prevent pathogens from entering the body.

Cytokines

Chemical messengers that help coordinate the immune response.

Phagocytosis

The process by which a cell engulfs and digests pathogens.

Inflammation

A response to infection characterized by heat, redness, swelling, and pain.

Chronic Infection

An ongoing infection with constant low-level viral production.

Persistent Infections

Infections where the virus remains in the host and can reactivate at a later time.

Fever

An increase in body temperature caused by pyrogens to slow pathogen growth and enhance immune activity.

Glycolysis

The metabolic process of breaking down glucose to pyruvate, yielding energy in the form of ATP.

TCA Cycle

Also known as the Krebs cycle, it processes Acetyl-CoA to produce ATP and electron carriers.

Fermentation

A metabolic process that occurs when oxygen is not available; regenerates NAD to allow glycolysis to continue.