Biology 2E Chapter 21: Viruses

These flashcards cover key concepts related to viruses, including definitions of terms and concepts relevant to the study of virology.

Viruses

Noncellular entities that cannot be considered living organisms by most biologists.

Virion

A single virus particle.

Lytic cycle

A viral infection cycle where the host cell is destroyed, releasing new viral particles.

Lysogenic cycle

A viral infection cycle where the virus integrates its DNA into the host genome, remaining dormant until activated.

Bacteriophage

A virus that infects bacteria.

Nucleic acid

The genetic material of a virus, which may be DNA or RNA.

RNA Virus

A virus whose genetic material is made of RNA, which may replicate and transcribe to produce proteins.

Vaccines

Preparations used to induce immunity against viruses by triggering immune protection.

Antiviral Drugs

Medications designed to inhibit viral replication and treat viral infections.

Baltimore Classification

A system that classifies viruses based on their genome type and method of mRNA production.

Cytopathic effects

Cell damage caused by viral replication, which can lead to cell death or illness.

Protein capsid

The protein shell that encases a virus's nucleic acid.

Viral envelope

An outer lipid bilayer derived from the host cell membrane that surrounds the capsid of some viruses.

Why do most biologists not consider viruses to be alive?

Viruses are noncellular entities that cannot be considered living organisms by most biologists. They lack the complete cellular machinery and independent metabolic processes typically associated with life.

What is the nature and variety of viral genomes?

The genetic material of a virus, known as nucleic acid, can be either DNA or RNA. An RNA virus is one whose genetic material is made of RNA, which may also replicate and transcribe to produce proteins.

Describe the main types of viral infection cycles.

The two main types of viral infection cycles are:

• Lytic cycle: A viral infection cycle where the host cell is destroyed, releasing new viral particles.
• Lysogenic cycle: A viral infection cycle where the virus integrates its DNA into the host genome, remaining dormant until activated.

How do the lytic and lysogenic virus cycles compare and contrast?

• Lytic Cycle: In this cycle, the host cell is destroyed as new viral particles are produced and released.
• Lysogenic Cycle: The virus integrates its DNA into the host genome and remains dormant. The host cell is not immediately destroyed, and the integrated viral DNA is replicated along with the host's genome during cell division. It can later transition to a lytic cycle.

How are viral infections prevented and/or treated?

• Prevention: Vaccines are used to induce immunity against viruses by triggering immune protection.
• **Treatment