Viral Replication Mechanisms and Their Impact on Host Cells

The video tutorial explains viral replication, focusing on how viruses, lacking organelles, must enter host cells to replicate. It details two main replication strategies: the lytic cycle, where viruses quickly replicate and lyse the host cell, and the lysogenic cycle, where viruses integrate into the host genome and remain dormant until activated. The tutorial covers virus entry methods, including bacterial phage injection and receptor-mediated entry for enveloped and non-enveloped viruses.

Why do viruses need to enter host cells to replicate?

• They lack their own genetic material.

• They need the host's organelles and ATP.

• They cannot survive outside a host.

• They need to hide from the immune system.

How do bacteriophages typically enter host cells?

• By endocytosis.

• By fusing with the cell membrane.

• By injecting their genetic material.

• By tricking cell receptors.

What is a characteristic of the lytic cycle?

• The virus remains dormant.

• The virus quickly replicates and lyses the host cell.

• The host cell remains alive.

• The virus integrates into the host genome.

What happens to the host cell during the lytic cycle?

• It becomes a permanent virus factory.

• It becomes immune to further infections.

• It divides rapidly.

• It is lysed, releasing new viruses.

In the lysogenic cycle, what does the virus do after entering the host cell?

• It destroys the host cell's DNA.

• It integrates into the host's genetic material.

• It immediately starts replicating.

• It exits the cell to find new hosts.

What triggers a virus in the lysogenic cycle to become active?

• A decrease in host cell nutrients.

• Exposure to UV light or other stressors.

• A lack of nearby host cells.

• The presence of other viruses.

What is a provirus or prophage?

• A virus integrated into the host genome and dormant.

• A virus that is actively replicating.

• A virus that has been destroyed by the host.

• A virus that has been expelled from the host.

What is the main advantage of the lysogenic cycle for a virus?

• Avoidance of host immune responses.

• Rapid replication and spread.

• Immediate destruction of the host cell.

• Long-term survival within the host.

Which cycle is more beneficial for a virus when there are many hosts available?

• Lysogenic cycle

• Both cycles are equally beneficial

• Lytic cycle

• Neither cycle is beneficial

What is the key difference between the lytic and lysogenic cycles?

• The lytic cycle leads to rapid virus production and host cell destruction.

• The lysogenic cycle results in immediate host cell lysis.

• The lysogenic cycle is faster than the lytic cycle.

• The lytic cycle involves integration into the host genome.