Lytic and Lysogenic Cycles Overview

The video tutorial explains viral replication, focusing on how viruses, lacking organelles, must enter host cells to replicate. It details two main methods of entry: bacteriophages injecting genetic material and other viruses using cell receptors or membrane fusion. Once inside, viruses can follow the lytic cycle, rapidly replicating and lysing the host cell, or the lysogenic cycle, integrating into the host genome and remaining dormant until activated. The tutorial clarifies these processes, emphasizing the strategic choices viruses make based on environmental conditions.

Why do viruses need to enter host cells to replicate?

• They need to hide from the immune system.

• They lack their own genetic material.

• They need the host's organelles and ATP.

• They cannot survive outside a host.

How do bacteriophages typically enter a host cell?

• By fusing with the cell membrane.

• By injecting their genetic material.

• By tricking the cell's receptors.

• By being engulfed by the cell.

What happens during the lytic cycle?

• The virus remains dormant.

• The virus integrates into the host genome.

• The virus takes over the host's machinery to replicate.

• The virus exits the host cell without causing damage.

What is the outcome of the lytic cycle for the host cell?

• The host cell repairs the viral DNA.

• The host cell continues to function normally.

• The host cell is lysed and destroyed.

• The host cell becomes immune to the virus.

In the lysogenic cycle, what is a provirus?

• A virus that integrates into the host's DNA.

• A virus that is destroyed by the host.

• A virus that causes immediate symptoms.

• A virus that immediately replicates.

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

• The presence of other viruses.

• Exposure to UV light or other stressors.

• A lack of nutrients.

• The host cell's death.

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

• The lytic cycle integrates into the host genome.

• The lytic cycle results in immediate replication and cell lysis.

• The lysogenic cycle causes immediate cell lysis.

• The lysogenic cycle uses the host's machinery for replication.

What is the term for a virus in the lysogenic cycle that is not actively replicating?

• Lytic virus

• Provirus

• Dormant virus

• Active virus

How does the lysogenic cycle benefit the virus when hosts are scarce?

• It makes the virus immune to host defenses.

• It keeps the host alive for future replication.

• It allows the virus to infect multiple hosts simultaneously.

• It allows the virus to replicate quickly.

What happens to the viral DNA during the lysogenic cycle?

• It integrates into the host's genome.

• It remains separate from the host DNA.

• It is destroyed by the host.

• It immediately starts replicating.