Comparing the Simple Structure of Plant and Animal Cells

Katherine Kolb
East Bethel Community School
Cedar, Minnesota
Using original activities from the Harcourt textbook, Living Things, Unit A and B, Lesson 1, "What are cells?", Delta Science Module, Small Things and Microscopes, and original lesson components.
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Summary

The students will conduct a scientific investigation by using a collection of examples of simple animal and plant cells and observing to compare their characteristics. They create a cell model to begin learning the basic parts of a cell. They observe various examples of plant and animal cells parts from illustrations and use microscopes to observe real plant and animal cells. They collect data on plant and animal cell parts/characteristics from the model, illustrations, and their observations of cells using microscopes. They create a drawing or a model showing a simple plant or animal cell identifying the cell parts that will be used for assessment. This activity follows lessons using microscopes and leads to lessons on the needs of living things. This activity is a good one to introduce or reinforce the use of science journals.

Learning Goals

The student will use guided scientific observation using a collection of models, visual material, and microscope slides to identify the following plant or animal cell parts: cell membrane, cytoplasm, nucleus, cell wall, chloroplasts, mitochondria, and vacuole.
  • The students will use guided, structured scientific inquiry to collect and record data on animal and plant cell parts/characteristics and then draw or create a model of a simple plant or animal cell, correctly labeling the parts.
  • The student will use a journal to record observations and drawings as they collect data.
  • The students will demonstrate their understanding of the parts/characteristics of plant and animal cells by identifying their classmates' drawings/model of a cell as either plant or animal.

Context for Use

This activity is used in a self-contained fourth grade classroom. Access to a classroom set of microscopes that are powerful enough to observe cell structure is needed. It is best to have a microscope for every two students and students should have completed lessons and be comfortable using microscopes. Information on how to construct a cell model and using microscopes is needed for teacher reference. You should have a set of commercially or teacher prepared microscope slides that show different kinds of cells and pictures or illustrations of cells. Students should have experience using microscopes and keeping a journal. It will take extra time, but this can be a good activity to introduce journaling if they have not journaled before. This activity will take about five 45-minute sessions but could go longer.

Description and Teaching Materials

Students begin the study comparing cells using the Harcourt textbook, Living Things Unit A and B, Lesson 1, "What are cells?" This lesson is introduced by creating a question(s) to use in the investigation that leads to having the students make a cell model. This activity creates a model using a gelatin mold/cytoplasm, malted milk ball/nucleus, raisins/mitochondria, and gelatin candies/vacuoles. They should draw and describe their cell in their journal. They decide how to collect and organize their data for further research.

Using microscopes, the students will prepare and look at a paper-thin layer of an onionskin and find the cell parts. I use Activity 7 from the Delta Science Module, Small Things and Microscopes, on pages 43-48. You should check each pair of students' microscope to see if they have actually focused correctly. Ask them which parts they can see and how they know it is that part. If one pair has a good example, have the others check it. Using notes or drawings have them record observations in their journals.

After they have had time to look at their slide and record their observations, discuss their findings together as a class. Encourage them to look in each other's microscopes to see how they look compared to theirs. You can have several draw their cell on a transparency or on the board to help with the group discussion. During the group discussion, you should draw a model for them to copy into their journals, also, to assure that they have all the parts and that they are labeled correctly. You should also provide a diagram that they can glue into their journals.

Follow the same procedure using cells the students have scraped from the inside of their cheek (gently scrape cells using a flat toothpick). I use Activity 9 from the Delta Science Module, Small Things and Microscopes, on pages 55-60. Provide a collection of illustrations and slides of plant and animal cells and/or videos for the students to observe to reinforce the understanding that cells are made up of similar parts.

As a closure activity, us a T-Chart or a Venn diagram and have students categorize the plant and animal cell parts. This can be done together as a class, in small groups, or individually. If done in a small group or individually, it is important that you still complete one together as a class to assure that everyone has an accurate chart or diagram. This can be done on the overhead, white board, chart paper, etc. to model the correct information. You can also provide a worksheet for them to label the parts.

Teaching Notes and Tips

We use the Harcourt Science Textbook, Life Science Modules A and B (copyright 2005). Prior to this lesson, students should have practiced using microscopes and understood the purpose of using microscopes. You will need a resource with activities on how to prepare slides and use a microscope. I use the Delta Science Module, Small Things and Microscopes. Prepare a few slides ahead of time just in case some students are not successful preparing their slides---the observation is the most important part. You need to define clear rules about how to move around the class if you have the microscopes on student desks. It is important that you provide accurate diagrams that should be included in the students' journals as fourth graders have varying degrees of skill in drawing diagrams. It helps if you have a collection of pictures, slides, and/or videos that show different cells but the activity will work if you skip this. The method of using the students' model drawing as part of the assessment is different because you not only use them as an individual assessment but also as the items/examples for a paper and pencil test. I used the Atlas of Science Literacy Volume I, and Benchmarks for Science Literacy published by the American Society for the Advancement of Science, Project 2061 as a foundation for my learning goals and concepts. Every district should have these resources!

Assessment

As an assessment, after the lesson each student will independently create a model or drawing of a plant or animal cell with all the parts labeled correctly. On the back of the drawing or on a piece of paper under the model they should indicate if it is a plant or animal cell. If this is to act as an assessment, the model or drawing should be completed in class during a class period. They should use the information in their journals. If you choose to have models as an option, you will need to have materials available.

After you have checked the individual cells using a checklist, have each student place their drawing or model on their desk. Place a sticky note on each desk with an alphabet letter. Give each student a recording worksheet that has the letters on it. Have them move from desk to desk recording by each letter on their worksheet if the cell is a plant or animal cell (they should move to each desk on a cue from you so it stays organized). After they have returned to their own desk, check the papers together in class to see how many they identified correctly. This can be included as part of your assessment and as scientists, they also get to see everyone's drawing/model. This helps you to evaluate if the individual drawing/model was clear for others and if the individual students remember how to identify both types of cells.

You can use their journals in assessment using a teacher created rubric.

Standards

Grade Level: Fourth
Strand: Life Science
Sub-Strand: A. Cells
Standard: The student will know that all organisms are composed of cells, which are the fundamental units of life.
Benchmark: 1. The students will recognize that cells are very small, and that all living things consist of one or more cells.
Sub-Strand: B. Diversity of Organisms
Standard: The student will know that living things can be sorted into groups in many ways.
Benchmark: The student will classify plants and animals according to their physical characteristics.

References and Resources