Download Teacher`s Guide Cells

Cells: Teacher’s Guide
Grade Level: 6-8
Curriculum Focus: Microscopic World
Lesson Duration: Two class periods
Program Description
It’s been more than 350 years since the microscope was invented, but scientists still use it to see the
world at a different scale. Take a larger-than-life look at human and plant cells, and watch these
tiny building blocks of life in action. Observe how the body repairs damaged cells after an
encounter with boiling water. This program includes four short segments.
Onscreen Questions
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How do human skin cells grow?
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What are the different cells in plants, and what properties do they have?
Lesson Plan
Student Objectives
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Discuss how children in Africa are affected by AIDS, based on information in the program.
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Read an article or Web site on this topic to analyze and summarize.
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Create a small poster inspired by the article, including images, excerpts, data, and quotes.
Materials
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Cells video and VCR, or DVD and DVD player
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Computer with Internet access
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Materials to create poster presentation (markers, colored pencils, glue, scissors, poster board)
Procedures
1. Review what students know about cells. A good way to do this is by watching and discussing
Cells. Then, find a diagram of a cell, label the organelles, and discuss their functions. Explain
that all cells share common characteristics, but plant and animal cells have important
Cells: Teacher’s Guide
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differences. Tell students they will be making their own plant and animal “cells” to understand
the differences in structure.
2. Prepare the yellow gelatin to a liquid state according to the recipe on the package. Then, add the
contents of the Knox gelatin envelope to it, creating a firmer substance; do not add any more
water.
3. Group students into pairs. Give each pair two plastic bags, one plastic sandwich container,
warm liquid gelatin, and assorted fruits.
4. Students will put one bag in the sandwich container as a liner and leave the other bag open on
the desk. Explain that the plastic bags represent cell membranes and the container represents a
cell wall. The lined container represents a plant cell, which has a cell membrane and a sturdy
cell wall. The bag on the desk represents an animal cell, which has just a cell membrane.
5. Have students place similar amounts of gelatin into each bag. Next they will add fruits to
represent different parts of the cell: cherries for lysosomes, mandarin oranges for mitochondria,
a plum for the nucleus, and green grapes for the chloroplast found in plant (but not animal)
cells. Then they’ll add pepper for ribosomes and yarn for endoplasmic reticulum. Finally, they
will close the bags with twist ties and place them in the refrigerator to set.
6. The next day, have students examine the two cells to note the structural differences. Ask
students these questions:
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What are their shapes?
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What affect does the cell wall have on the plant cell?
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Why do you think plant cells have sturdy walls?
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How does this help the plant survive?
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How does this influence the structure of the plant itself?
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Why don’t animal cells have walls?
7. After this discussion, students should understand that in animal cells the cell membrane
controls what can enter (food and other useful substances) and exit (waste). The plant cell wall,
made of cellulose, is tougher and thicker than the cell membrane inside it. Cellulose protects
and supports plant cells. Food can’t enter through the plant cell’s cell wall, but this is okay
because plant cells make their own food from sunlight, carbon dioxide, and water.
8. Have the student pairs create and present charts comparing animal and plant cells. As a class,
discuss the charts and create a master chart that includes all findings.
9. If time allows, have students use a microscope to examine plant cells and compare what they
see to their models.
Assessment
Use the following three-point rubric to evaluate students’ work during this lesson.
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3 points: Students built accurate cell models; showed a strong understanding of the
structural differences of animal and plant cells; were active in class discussions.
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Cells: Teacher’s Guide
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2 points: Students built somewhat accurate cell models; showed some understanding of the
structural differences of animal and plant cells; participated in class discussions.
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1 point: Students built inaccurate or incomplete cells models; lacked an understanding of
the structural differences of animal and plant cells; did not participate in class discussions.
Vocabulary
DNA
Definition: A nucleic acid consisting of large molecules shaped like a double helix; associated
with the transmission of genetic information; short for deoxyribonucleic acid
Context: DNA contains the hereditary information necessary for cell life.
mitochondria
Definition: Rod-shaped or spherical organelles in the cytoplasm that release energy through a
process called respiration
Context: Mitochondria produce the energy that cells need to function.
mitosis
Definition: The process by which a cell divides to create two exact copies of itself
Context: Mitosis ensures that each new cell will be identical to its parent cell.
nucleus
Definition: A large membrane-bound structure within a living cell, containing hereditary
material and controlling its metabolism, growth, and reproduction
Context: The nucleus contains the cell’s genetic material.
organelles
Definition: The internal structures of a cell, including the nucleus and mitochondria
Context: Each type of organelle in the cell has a specific function.
Academic Standards
National Academy of Sciences
The National Science Education Standards provide guidelines for teaching science as well as a
coherent vision of what it means to be scientifically literate for students in grades K-12. To view the
standards, visit http://books.nap.edu.
This lesson plan addresses the following science standard:
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Life Science: Structure and function in living systems
Mid-continent Research for Education and Learning (McREL)
McREL’s Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education
addresses 14 content areas. To view the standards and benchmarks, visit http://www.mcrel.org/.
Published by Discovery Education. © 2005. All rights reserved.
Cells: Teacher’s Guide
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This lesson plan addresses the following national standards:
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Language Arts—Viewing: Uses viewing skills and strategies to understand and interpret
visual media; Reading: Uses reading skills and strategies to understand and interpret a
variety of informational texts
Support Materials
Develop custom worksheets, educational puzzles, online quizzes, and more with the free teaching tools
offered on the Discoveryschool.com Web site. Create and print support materials, or save them to a
Custom Classroom account for future use. To learn more, visit
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http://school.discovery.com/teachingtools/teachingtools.html
DVD Content
This program is available in an interactive DVD format. The following information and activities are
specific to the DVD version.
How To Use the DVD
The DVD starting screen has the following options:
Play Video—This plays the video from start to finish. There are no programmed stops, except by
using a remote control. With a computer, depending on the particular software player, a pause
button is included with the other video controls.
Video Index—Here the video is divided into four parts (see below), indicated by video thumbnail
icons. Watching all parts in sequence is similar to watching the video from start to finish. Brief
descriptions and total running times are noted for each part. To play a particular segment, press
Enter on the remote for TV playback; on a computer, click once to highlight a thumbnail and read
the accompanying text description and click again to start the video.
Curriculum Units—These are specially edited video segments pulled from different sections of the
video (see below). These nonlinear segments align with key ideas in the unit of instruction. They
include onscreen pre- and post-viewing questions, reproduced below in this Teacher’s Guide. Total
running times for these segments are noted. To play a particular segment, press Enter on the TV
remote or click once on the Curriculum Unit title on a computer.
Standards Link—Selecting this option displays a single screen that lists the national academic
standards the video addresses.
Teacher Resources—This screen gives the technical support number and Web site address.
Published by Discovery Education. © 2005. All rights reserved.
Cells: Teacher’s Guide
Video Index
I. Skin Deep (3 min.)
Michelle fell into scalding hot bath water when she was just a baby, badly burning her arms and
legs. Learn about the technique doctors used to grow replacement skin cells for Michelle.
II. A Brief History of Cells (4 min.)
Without the microscope, our knowledge of cells would be greatly limited. Witness the historical
evolution of the microscope, and discover what this invention has done for modern science.
III. Inside Cells (3 min.)
Learn about single-cell organisms, as well as the structure of animal cells and the many different
types of cells found in every human being.
IV. The Inner Workings of Plants (4 min.)
Whether enormous sequoia trees or small blades of grass, plants are all made up of the same
building blocks—cells. Explore the structure and properties of plant cells.
Curriculum Units
1. Skin Cells
Pre-viewing question
Q: What is the most serious injury you have ever had?
A: Answers will vary.
Post-viewing question
Q: What are some things you can do to help keep your skin healthy?
A: Answers will vary.
2. Under the First Microscopes
Pre-viewing question
Q: What did the invention of the microscope do for science?
A: It allowed scientists to study things that are too small to be seen by the naked eye.
Post-viewing question
Q: What was botanist Robert Brown’s discovery?
A: Brown discovered that inside every plant cell was a blob-like structure, which he called the
nucleus.
3. The Building Blocks of Life
Pre-viewing question
Q: Why is it important that we study cells?
A: Answers will vary.
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Cells: Teacher’s Guide
Post-viewing question
Q: What do you think are the most important cells in your body?
A: Answers will vary.
4. Amoebas, Animal Cells, and Human Cells
Pre-viewing question
Q: How do single-cell organisms differ from other living beings?
A: These organisms are able to make food, grow, and reproduce all on their own.
Post-viewing question
Q: What does a cell membrane do for a cell?
A: A cell membrane acts like a barrier, controlling what passes in and out of a cell.
5. Plant Cells
Pre-viewing question
Q: What are some of the many ways in which we use plants?
A: Answers will vary.
Post-viewing question
Q: What is the difference between a cell membrane and a cell wall?
A: A cell membrane is not as rigid or as strong as a cell wall. Animal cells have membranes; plant
cells have membranes and walls
6. Photosynthesis and Root Cells
Pre-viewing question
Q: Why are leaves green?
A: Leaf cells contain many small particles (chloroplasts) that are filled with chlorophyll, a green
chemical.
Post-viewing question
Q: What is photosynthesis?
A: This chemical reaction inside a plant’s leaves uses the sun’s energy to convert water and carbon
dioxide into sugars, which become food for the plant.
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