Download Student Exploration Sheet: Growing Plants

Name: ______________________________________
Date: ________________________
Student Exploration: Virus Lytic Cycle
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?
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2. Have you ever been infected with a virus, such as the cold virus or flu virus? ____________
3. If so, how did the virus affect you? _____________________________________________
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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:
Lytic cycle
Get the Gizmo ready:
 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. 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
1
↓
2
↓
3
↓
4
↓
5
(Activity A continued on next page)
Activity B:
Get the Gizmo ready:
Spread of
infection
 If necessary, click Reset.
Question: How does a viral infection spread?
1. Predict: Suppose that a virus infects a small population of bacteria. Predict how the numbers
of viruses, infected cells, and uninfected cells will change as the infection progresses. On
the blanks below, write increase, decrease, or stay the same.
Viruses: _______________________
Infected cells: _______________________
Uninfected cells: _______________________
2. Observe: Click Play (
), and watch the simulation. Describe what you see.
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3. Test: Click Reset, and Select the BAR CHART tab. Turn on Show numerical values. Click
Play, and watch each bar as the simulation runs. What do you notice, and how does this
compare to your predictions?
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Student Exploration: Disease Spread
Vocabulary: disease, epidemic, infect, infectious disease, pathogen
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
4. Why do you think it is important to cover your mouth when you cough? _________________
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5. Why should you always wash your hands before you eat? __________________________
Gizmo Warm-up
When a person has a disease, his or her normal body
functions are disrupted. Some diseases, such as
diabetes and most cancers, are not spread from one
person to another. But other diseases, such as the flu
and strep throat, can be spread. These diseases are
known as infectious diseases. Infectious diseases are
caused by viruses, bacteria, and other agents known as
pathogens.
In the Disease Spread Gizmo™, you will be able to
observe how various pathogens can spread through a
group of people. Click Play (
) and observe.
3. Describe what happened on the SIMULATION pane: _______________________________
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4. Look at the color key on the bottom right of the Gizmo. What is happening when a person
changes color? ____________________________________________________________
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Get the Gizmo ready:
Activity A:
Person-to-person
transmission
 Click Reset (
).
 On the CONTROLS tab under Active Diseases,
turn off Foodborne and turn on Person to person.
 Set the Number of people to 5.
Question: What factors affect how quickly a pathogen spreads from person to person?
2. Identify: Select the SIMULATION tab on the left and the TABLE tab on the right. (You will
want the table tab open to answer question C.)
A. What does the purple person represent? __________________________________
B. Click Play, and observe the simulation for a while. What must happen for the disease
to spread from one person to another? ____________________________________
C. How long did it take to infect five people? _________________________________
3. Experiment: Click Reset. Change the Number of people to 15. Click Play, and record how
long it takes to infect five people. Then repeat the experiment when there are 25 people and
35 people in the room.
Number of people in room
Time required to infect five people (hr)
15
25
35
4. Interpret: Study the data you collected. What trend do you see in the data, and how would
you explain it? _____________________________________________________________
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Activity B:
Foodborne and
airborne
transmission
Get the Gizmo ready:
 Click Reset.
 On the CONTROLS tab under Active diseases,
turn off Person to person and turn on Foodborne.
Question: How do foodborne and airborne pathogens spread?
1. Observe: Select the SIMULATION tab. Click Play and closely watch the people moving
around the room.
A. What does each person do just before becoming infected? ____________________
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B. How are foodborne pathogens transmitted? ________________________________
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C. If a person in the simulation never eats or drinks anything from the buffet table, is it
possible for them to become sick with the foodborne disease? Explain your answer.
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Get the Gizmo ready:
Activity C:
Observations
 Click Reset (
).
 Make changes to the simulation. Describe what
happens.
1. Change #1:
a. Describe what you changed:
b. What was the result?
2. Change #2:
a. Describe what you changed:
b. What was the result?
3. Change #3:
a. Describe what you changed:
b. What was the result?