Science 7 Standard 4 08-06
8/22/02
7:49 AM
Page 139
Standard Indicator
7.4.4
Cell Cycle
Purpose
Students will explain that cells continually divide to make more cells
for growth and repair.
Materials
For the teacher: long balloon, water, confetti or some other small objects
that represent organelles, transparency of Black Line Master (BLM)
Cell Division, overhead projector
For each student: copy of BLM Cell Division
For each pair of students: various craft materials to model the
cell cycle, such as pipe cleaners for chromosomes, string for spindle
fibers, etc.
incorporating
TECHNOLOGY
Direct students to the
Cells Alive! Web site to
view a video clip and
animation of mitosis
in an animal cell:
www.cellsalive.com/
mitosis.htm.
Activity
extending
THE
B. Pre-Activity Discussion
1. Direct students to roll their shirt sleeves and rub their hands
a few times across the skin on their arms.
2. Tell students that they are wiping off millions of dead skin cells
as they rub their arms.
3. Ask students: “If you are wiping off millions of dead skin cells,
why does your skin look the same and why do you not ‘run out’
of skin cells?”
4. Discuss students’ explanations and explain that cells continually
divide to make more cells for growth and repair of skin and other
organs and tissues. Explain that the entire process of cell growth,
formation, and division is called the cell cycle.
5. Explain that most human cells divide in a process called mitosis.
6. Ask students to give other examples of evidence of growth and
repair (e.g., healing a cut in the skin, growth stages to
adulthood, etc.).
Have students
research how cancer
cells behave and ask
them to relate it to
mitosis and the
cell cycle.
ACTIVITY
C. Activity
1. Show the balloon to the class and explain that it is a model of
a cell. Ask students: “How do you think animal cells divide?”
(continued)
Standard 4 / Activity 2
Indiana Science Grade 7 Curriculum Framework, October 2002
Standards Links
7.4.1, 7.7.2
page 139
Standard 4
A. Pre-Activity Preparation
Fill a long balloon with water and confetti and seal the balloon.
Science 7 Standard 4 08-06
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Page 140
Activity (continued)
2. Twist the balloon into two parts; be sure organelles are included
on both sides.
3. Explain that as the cell divides, each new cell receives organelles
and a copy of genetic information in the form of chromosomes
from the parent cell.
4. Ask students: “Why is it important that the new cells receive
a copy of the genetic information?”
5. Discuss how chromosomes contain all of the instructions
for the cell’s function and growth.
D. Cell Cycle and Mitosis
1. Show the transparency of the BLM Cell Division on the overhead
and distribute a copy of the BLM to each student.
2. Explain to students that scientists have identified six basic steps
in the cell cycle.
3. Point out each stage on the transparency as you explain the cell
cycle. Explain that after the two daughter cells form, the cycle
begins again.
4. Have students review the cycle on their own copies of the BLM.
Standard 4
E. Model It!
1. Divide students into pairs, distribute craft materials, and ask:
“How could you make a model showing the cell cycle?”
2. Monitor and guide students as they work. Ask questions such as:
“Why do cells go through mitosis? Why is it so important for the
genetic material/chromosomes to be copied to all daughter cells?”
3. Have each pair of students share their models with the class.
Classroom Assessment
Basic Concepts and Processes
At the end of the activity, ask questions, such as the following:
Why do cells continually divide and what is the name of this
process?
How do you know that when you get a cut, your skin will
grow back and heal?
page 140
Standard 4 / Activity 2
Indiana Science Grade 7 Curriculum Framework, October 2002
Standard 4 / Activity 2
Indiana Science Grade 7 Curriculum Framework, October 2002
CYTOKINESIS The cell membrane
pinches in around the
middle of the cell. Each daughter
cell ends up with the same
number of identical chromosomes.
TELOPHASE The chromosomes relax.
A membrane forms
around each region of
chromosomes.
genetic material
daughter
chromosome
ANAPHASE The chromosomes pull apart and
the daughter chromosomes move
to opposite ends of the cell.
daughter
chromosome
METAPHASE The chromosomes are
pulled by spindle fibers
to line up across the middle
of the cell.
7:49 AM
PROPHASE - The genetic material
“shrinks” or condenses to form
chromosomes. Spindle fibers form a bridge
between the ends of the cell and each
chromosome attaches to a spindle fiber.
replicated
chromosomes
(sister chromatids)
spindle fibers
8/22/02
nuclear
membrane
INTERPHASE - The cell grows
to its mature size and makes a
copy of its genetic material
and other cell parts.
Cell Division
Name:
Science 7 Standard 4 08-06
Page 141
Black Line Master 1
page 141
Science 7 Standard 4 08-06
8/22/02
7:49 AM
Page 142
Cell Division
Teacher Directions
Make a transparency copy of the BLM Cell Division and distribute a copy of the BLM to each
student in the class. Go through each stage in the cell cycle, pointing to the diagrams on the
transparency. Have students review the cell cycle while looking through their own copies of the
BLM. Divide students into pairs and distribute craft materials. Direct them to use the craft
materials to model the cell cycle.
Answer Key
Not applicable.
Black Line Master 1
page 142
Standard 4 / Activity 2
Indiana Science Grade 7 Curriculum Framework, October 2002