Chapter 18.2, Problem 7MI

Summary Introduction

To label:

The steps A, B, C, D and E of a lytic cycle in the given figure

Introduction:

A virus must enter a host cell in order to replicate. Different organisms have receptors for different types of viruses. The virus uses the host cell to replicate by either the lytic cycle or lysogenic cycle. Viruses that replicate through lytic cycle produce active infections.

Answer to Problem 7MI

1. Attachment
2. Entry
3. Replication
4. Assembly
5. Lysis and Release

Explanation of Solution

In a lytic cycle, a virus uses host cell’s energy and raw materials to make new viruses. The various steps of a lytic cycle are as follows:

1. The viral cell attaches to the host cell using specific receptors on the plasma membrane of the host cell.
2. After attaching successfully to the host cell, the virus injects the genetic material into the cytoplasm of the host cell. So the viral material enters the host cell.
3. In the lytic cycle, the host cell makes many copies of viral RNA or DNA. The viral genes instruct the host cell to make more viral protein capsids and enzymes needed for viral replication.
4. The protein coat forms around the nucleic acid to form new viruses. New virus particles are assembled.
5. These new viruses leave the cell by exocytosis or by causing the cell to burst or lyse releasing new viruses that are free to infect other cells.