Viruses, Viroids, and Prions - General Characteristics and Biology

Flashcards covering the characteristics, lifecycle, and classification of viruses, viroids, and prions based on the lecture notes.

Viruses

Obligatory intracellular parasites that require living host cells to multiply.

Bacteriophage

Viruses that specifically infect bacteria.

Plaque-forming units (PFU)

A measure of the number of infectious viruses present, expressed as clearings formed on a bacterial lawn.

Virion

Complete, fully developed viral particle composed of nucleic acid and a protein coat.

Capsid

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

Envelope (in viruses)

Lipid, protein, and carbohydrate coating found in some viruses.

Spikes (in viruses)

Projections from the outer surface of some viruses that aid in attachment to host cells.

Helical virus

Virus with a hollow, cylindrical capsid structure.

Polyhedral virus

Virus with many-sided geometrical structure.

Viroid

Infectious agents composed solely of a short strand of circular, single-stranded RNA, lacking a protein coat.

Lytic cycle

A viral multiplication cycle resulting in the lysis and death of the host cell.

Lysogenic cycle

A viral multiplication cycle where phage DNA is incorporated into the host DNA without killing the host.

Cytopathic effect (CPE)

The observable deterioration of virally infected cells in culture.

One-step growth curve

A graph representing the stages of viral multiplication, showing increase followed by a decrease.

Prophage

Inserted phage DNA in the host cell's DNA during the lysogenic cycle.

Adenoviridae

Family of viruses with double-stranded DNA, known for causing respiratory infections in humans.

Herpesviridae

Family of enveloped double-stranded DNA viruses that include those causing cold sores and chickenpox.

Oncogenic viruses

Viruses that can induce tumors by integrating into host cell DNA.

TSTA (tumor-specific transplant antigen)

A unique antigen found on the surface of transformed cells harboring oncogenic genetic material.

RNA-dependent RNA polymerase

Enzyme used by RNA viruses to replicate their RNA in the host's cytoplasm.

Reverse transcriptase

Enzyme used by some viruses to synthesize DNA from RNA.

Attachment (viral multiplication)

The first step in viral infection, where viruses attach to the host cell membrane.

Entry (viral multiplication)

The process by which a virus enters a host cell, often via receptor-mediated endocytosis or fusion.

Uncoating (viral multiplication)

The process of releasing viral nucleic acid from the capsid inside the host cell.

Budding (in viral release)

Method of viral exit where enveloped viruses leave the host cell by forming vesicles.

Fusion (in viral entry)

Process where the virus membrane merges with the host cell membrane for entry.

Cytomegalovirus (CMV)

A member of the herpesvirus family associated with mononucleosis and other systemic infections.

Papovaviridae

Family of nonenveloped double-stranded DNA viruses, including the papillomavirus.

Hepatitis B virus (HBV)

An enveloped virus causing liver infection, belonging to the Heptadnaviridae family.

Subacute sclerosing panencephalitis

A rare progressive neurological disorder caused by the measles virus, typically fatal.

Transformation (of cells)

The process in which normal cells become cancerous due to viral infection.

Persistent viral infection

An infection that remains gradual over long periods with potential for reactivation.

Sarcoma

A type of cancer that originates in connective tissue.

Adenocarcinoma

A cancer that originates in glandular epithelial tissue.

Viroid vs Virus

Viroids consist only of RNA and lack a protein coat, unlike viruses which contain nucleic acid and a protein coat.

Embryonated eggs

Living eggs used in laboratory settings to grow animal viruses.

Continuous cell lines

Cell cultures derived from permanent cell lines that can be used for viral cultivation.

Latent viral infections

Infections where the virus remains dormant within the host for long periods.

Viral Taxonomy

The categorization of viruses into orders, families, and genera based on genetic relationships.

Viral species

A group of viruses sharing the same genetic information and ecological niche.

Virocarcinogenesis

The process by which viruses induce cancer.