Question

Differentiate between the lysogenic and lytic cycles.(1 point)
Responses

The virus injects DNA into the host cell during the lysogenic cycle.
The virus injects DNA into the host cell during the lysogenic cycle.

The host cell copies its own DNA during the lytic cycle.
The host cell copies its own DNA during the lytic cycle.

Viral proteins are synthesized during the lysogenic cycle.
Viral proteins are synthesized during the lysogenic cycle.

The host cell is destroyed during the lytic cycle.
The host cell is destroyed during the lytic cycle.

Answer 1

Correct distinction (brief):

- Lysogenic cycle: viral DNA integrates into the host genome (prophage) and is replicated along with the host DNA without making new virions; the host cell remains alive. Viral genes are largely repressed (so viral proteins are not synthesized except regulatory proteins).
- Lytic cycle: the virus takes over the host machinery to replicate viral genome and synthesize viral proteins, assemble new virions, and then lyses/destroys the host cell.

Evaluation of the given statements:
- "The virus injects DNA into the host cell during the lysogenic cycle." — Not a defining feature (injection occurs at initial infection and can lead to either cycle).
- "The host cell copies its own DNA during the lytic cycle." — False (host DNA is often degraded; viral replication predominates).
- "Viral proteins are synthesized during the lysogenic cycle." — False (viral genes are mostly repressed in lysogeny).
- "The host cell is destroyed during the lytic cycle." — True.