Viruses

What defines a virus as an acellular particle?

A virus is an acellular particle that infects a host cell, directing it to produce progeny particles.

What is the composition of a virus particle, or virion?

A virion generally consists of a viral genome (DNA or RNA) contained within a protein capsid.

What are bacteriophages?

Bacteriophages are viruses that specifically infect bacteria.

What is a prophage?

A prophage is a bacteriophage that integrates its genome into its bacterial host's genome.

What is a provirus?

A provirus is an integrated viral genome within a human cell.

What is the virome?

The sum of viral populations in an ecosystem.

How do acute viruses affect host populations?

Acute viruses rapidly kill their hosts, acting as predators or parasites that limit host population density.

What is the host range of a virus?

The range of host species infected by a given virus.

What types of viral genomes exist?

Viral genomes can be DNA or RNA, single-stranded or double-stranded, and can be linear, circular, or segmented.

What are icosahedral viruses?

Icosahedral viruses are polyhedral with 20 identical triangular faces and exhibit rotational symmetry.

What defines a temperate phage?

A temperate phage can either lyse cells or integrate its genome as a prophage, allowing it to enter a lysogenic cycle.

What is the role of CRISPR in bacterial defense against viruses?

CRISPR serves as a bacterial immune system by integrating phage DNA sequences, providing adaptive immunity.

How do animal viruses typically enter host cells?

Most animal viruses enter their host cells as virions.

What is oncogenesis and how do oncogenic viruses contribute to it?

Oncogenesis is the process by which viruses transform host cells to proliferate abnormally, often by expressing virally-encoded oncogenes or integrating into host chromosomes.

What is the significance of the burst size in viral culture?

The burst size is the characteristic number of viruses produced per host cell during viral replication.

What is viral replication?

Viral replication is the process by which a virus produces copies of itself within a host cell.

What are viral vectors?

Viral vectors are modified viruses used to deliver genetic material into cells for therapeutic purposes.

What is a lytic cycle?

The lytic cycle is a viral reproductive cycle that culminates in the destruction of the host cell.

What is a lysogenic cycle?

The lysogenic cycle is a viral reproductive cycle where the viral genome integrates into the host genome and replicates without destroying the host.

What is a viral envelope?

A viral envelope is a lipid membrane surrounding some viruses, acquired from the host cell during viral release.

What are emerging viruses?

Emerging viruses are newly identified viruses that are increasing in incidence or geographic range.

What is the function of viral proteins?

Viral proteins are involved in various functions, including attachment to host cells, evading the immune system, and replicating the viral genome.

How do viruses vary in size?

Viruses can vary widely in size, typically ranging from about 20 to 300 nanometers in diameter.

What role does the immune system play in viral infections?

The immune system detects and responds to viral infections to eliminate or control the virus.

What is the importance of viral diversity?

Viral diversity helps viruses adapt to new hosts and environments, increasing their survival.

What is an antigenic shift?

An antigenic shift is a major change in the surface proteins of a virus, which can lead to new strains that evade the immune system.

What are zoonotic viruses?

Zoonotic viruses are viruses that can be transmitted from animals to humans.

What is a vaccine and how does it work?

A vaccine is a biological preparation that provides acquired immunity to a particular infectious disease by stimulating the immune response.

What is antiviral therapy?

Antiviral therapy is the use of medication to treat viral infections by inhibiting the development of the virus.

What is host cell tropism?

Host cell tropism refers to the preference of a virus to infect certain types of cells within a host organism.

What is a viral mutation?

A viral mutation is a change in the viral genome that can lead to variations in viral traits, such as infectivity or resistance to treatment.

What are retroviruses?

Retroviruses are a type of virus that transcribes their RNA into DNA after entering a host cell, integrating into the host genome.

What role do vectors play in viral transmission?

Vectors are organisms, such as insects or rodents, that transmit viruses from one host to another.

What is herd immunity?

Herd immunity is the resistance to the spread of a contagious disease within a population when a sufficient proportion of individuals are immune.

What is viral shedding?

Viral shedding is the release of virus particles from an infected host, which can spread the infection to new hosts.