Student Exploration: Virus Lytic Cycle
Directions: Follow the instructions to go through the simulation. Respond to the questions and
prompts in the orange boxes.
Vocabulary: bacteriophage, capsid, host cell, lyse, lytic cycle, virus
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. A computer virus is a program that can copy itself and infect a computer without the
permission of the owner. How do you think a computer virus compares to a real virus?
similar to a computer virus, a real virus also copies the genetic information and corrupts it
and sends it to other cells to corrupt those cells as well.
2. Have you ever been infected with a yes, a cold virus
virus, such as the cold virus or flu
virus?
3. If so, how did the virus affect you? sore throat, weakness, runny nose.
Gizmo Warm-up
A virus is a microscopic particle that can infect a cell. Viruses
are primarily composed of a protein coat, called a capsid,
and nucleic acid. In the Virus Lytic Cycle Gizmo™, you will
learn how a virus infects a cell and uses the cell to produce
more viruses.
1. Viruses are extremely small. A typical virus is about
100 times smaller than a single cell, such as a
bacterium. Label the virus and a bacterial cell in the
image at right.
2. Bacteriophages are viruses
that infect bacteria. Based on
the diagram at left, label the
head, tail, tail fibers, and the
strand of nucleic acid in the
image at right.
, Activity A: Get the Gizmo ready:
Lytic cycle ● If necessary, click Reset ( ).
Introduction: Unlike living organisms, viruses cannot reproduce on their own. Instead, viruses
infect host cells, taking over the cell’s machinery to produce more viruses. This process is called
the lytic cycle.
Question: What are the steps of the lytic cycle?
1. 75.Observe: Use the navigation arrows on the DESCRIPTION tab to read about the stages
of the lytic cycle. Using your own words, summarize each step of the cycle.
Step Summary
a lytic bacteriophage virus attaches itself to the bacterial cell.
1 virus is a simple structure that is composed of a protein
capsid, nucleic acid (DNA or RNA) and a tail section
↓
The virus injects its nucleic acid into the bacterial cell. The nucleic acid uses the
cell’s ribosomes to make virus proteins. The proteins break up the cell’s DNA.
2
↓
the virus capsid and tail detaches from the cell and disintegrates. the viral nucleic
acid takes over and directs the production of new virus proteins and nucleic acid.
3
↓
The virus proteins and virus nucleic acid combine together into new viruses.
4
↓
special proteins produced by the viral nucleic acid cause the host bacterial cell
enter the lytic cycle, which destroys the cell in the process. The numerous new
5
viruses can infect other cells