Lesson Overview:
In this lesson, students will gain an understanding of the components of a cell. They will match definitions of organelles with the organelle name, research the organelle’s form and function, and contribute to a class drawing of a cell by depicting a specific organelle within the composite cell. Through this lesson, students will explore answers to the essential question: How are "form" and "function" related in biology?
Length of Lesson:
Two 45-minute periods
Notes:
This lesson is particularly suitable for students in grades 6-8.
Instructional Objectives:
Students will:
- match definitions of organelles with the organelle name.
- research the properties and functions of the organelles in a cell.
- draw the organelle to scale based on the size of the contour animal cell hanging on the wall of the class.
- present research results to the class and position their drawn organelle in its appropriate place on a class diagram of an animal cell.
Instructional Plan:
Introduction
Explain to the students that they will work in pairs or small groups to define, research, and draw an organelle. Allow students time to review the resources available to them in the classroom, including the books on cells and bookmarked Internet sites they will use for their research.
Introduce the topic of cells to students. Introduce the essential question, "How are "form" and "function" related in biology?" and elicit answers from the students. Discuss the sizes of cells (microscopic) and their roles in the human body. Discuss and question the students on the role of organs in our bodies. Use human organs as an analogy for cellular organelles.
Discuss the idea that the cell is a system, consisting of interdependent parts with specific roles and functions. Using the Vocabulary Handout, introduce the concept of the organelle and highlight new vocabulary words and their meanings.
Scientific Illustrations
As students begin to draw the cell and its various forms you might want to have them visit Science and the Artist's Book, an online exhibition from the Smithsonian Institution Libraries and the Washington Project for the Arts. Here, students can access various scientists’ illustrations. Point out to students the importance of accuracy and drawing to scale in scientific illustration. Students should keep this in mind as they continue with and complete their own drawings/projects. If you can project these images onto a screen, view and discuss each illustrator’s work with students. Identify similarities and differences between the works, charting students’ responses on a Venn diagram.
You may also wish to take students to the Ambleside Museum’s Beatrix Potter site. Students may be familiar with Potter as the author and illustrator of the famous children’s series The Tales of Peter Rabbit, but it may surprise them to learn that she was also an avid scientific illustrator. Potter believed in recording everything she saw and therefore did much in the way of scientific illustration. Many of her scientific illustrations of flora and fauna provided inspiration for illustrating her children’s books. If you can get a copy of the original illustrated version of The Tales of Peter Rabbit, it would be interesting to have students compare the artwork in the book to Potter’s scientific illustrations.
Researching and Making an Organelle
Direct students’ attention to the outline of the class cell hanging on the wall. Discuss the concept of scale. Explain to students that they will be asked to fit their organelles within the outline of the cell. Model this by using one of the organelles on the list (the golgi apparatus or mitochondria work well). Draw three sizes of the organelle, only one of which is to scale. Have the students pick the most appropriate version. (Eyeballing or estimating the correct scale is sufficient.)
Distribute all of the cards (ten names of organelles and ten definitions). Have students find their partners by matching their definition to the vocabulary card. Once matched, have the paired students research, analyze, sketch to scale, color, and cut out their organelle. (Please note that a different approach is required for the cilia. The students responsible for the depiction of the cilia should brainstorm on how best to make it. One idea is to fringe-cut the edges of the composite cell and folding back every other strip. The students can then color the visible fringe.) The following Web site will be helpful in conducting research:
Before having students draw their organelles, review simple color theory with the students. Have a color wheel in the classroom. (This is something that should remain up all year, as students will be involved in artistic endeavors from time to time.) Have students look at the color wheel and identify the primary colors (red, yellow, and blue). Review with students the fact that all other colors are made from these primary colors, which unlike secondary colors, cannot be made by mixing other colors together. Have students explain what the secondary colors are. (Secondary colors are made from mixing two primary colors together. Red and yellow make orange, yellow and blue make green, and red and blue make purple.) Another important color technique you may wish to highlight for students is the fact that you can lighten a color by adding white and darken it by adding black.
Students should use the available resources to extend their understanding of the cell’s form and function beyond the definition given on the card. The students will take notes on their organelle and rewrite a description of its form and function in their own words. The text will be used as an aid in the group’s oral presentation to the class.
To depict the cell, students will select colors to effectively communicate their organelle and to ensure the organelle contrasts well with the background cell. Students should reflect upon the effectiveness of their choices. Encourage the students to use vivid, complementary colors. Allow students 30 minutes to complete this task. Fill out the Our Composite Cell Assessment Rubric as the students work.
Allow students to present their drawing and the results of their research to the whole class. Fill out the Assessment Rubric during the students’ group presentations.
Have students position the drawings of their organelles in the appropriate location within the animal cell depiction hanging on the classroom wall.
Close with a discussion on what the students learned from the lesson. Refer back to the lesson’s essential question. Include a discussion on the use of color of both the individual organelles as well as the composite cell.
Assessment:
Critique the composite cell as a class. For individual assessment, refer to the Our Composite Cell Assessment Rubric and the Assessment Rubric completed during the student presentations.
Extensions:
Go on to Lesson 2 in this unit, How Do Cells Reproduce?.
Sources:
Print
- Balkwill, F., and Rolph M. Balkwill. Cell Wars. London: Harper Collins, 1999.
- Balkwill, F. and Rolph M. Balkwill. Cell are Us. Minneapolis: Carolrhoda Books, Inc., 1990.
- Berger, Melvin. Germs Make Me Sick. Revised ed. New York: Harper Collins, 1995.
- Brown, Robert J. 333 More Science Tricks and Experiments. Blue Ridge Summit, PA: Tab Books, 1984.
- Patent, Dorothy Hinshaw. Microscopic Animals and Plants. New York: Holiday House, 1974.
- Ruiz, Andre Llamas. The Life of a Cell. New York: Sterling publishing Co., Inc., 1996.
Web:
Authors:
-
Susan Born-Ozment, Teacher
Oyster Bilingual Elementary
Washington, DC
