A World of Cells Part One: Observing Cheek Cells Part Two: Animal Cell Models Part Three: Plant Cells Models
FCAT Connection:	Strand F: Processes of LIfe Standard 1 Benchmark: SC.F.1.3.2 and SC.F.1.3.5
Overview:	This lesson plan includes three different activities that give students a comprehensive introduction to cell structures and processes. In Part One, students observe human cheek cells with a microscope. In Part Two, students make models of animal cells. In part three, students make models of plant cells.
Literature Connection:	The Microscope Book by Shar Levine and Leslie Johnstone The Magic School Bus Inside the Human Body by Joanna Cole Yuck! A Big Book of Little Honors by Robert Snedden

	Part One: Observing Cheek Cells
Materials	Toothpicks Microscope slides and cover slips Iodine-water in plastic dropper bottles Eye droppers if plastic dropper bottles are not used Microscopes or a Flex-Cam with television monitor "Observing Human Cheek Cells" data sheets
Procedures	Instruct the class to complete the "K" and "W" sections of a K-W-L on cells. Review the procedures for using a microscope and for distributing the lab materials with students. Give the following instructions to the students: Draw how you think a human cheek cell will look when viewed with a microscope. Put a microscope slide on a paper towel. Put 1 drop of iodine-water solution on your microscope slide. Gently scrape the inside of your cheek two or three times with a toothpick. It will look like nothing is on the toothpick, but there will probably be plenty of cells to see with the microscope. Stir the cheek materials into the iodine-water solution on your slide. Carefully put a cover slip over the mixture on your slide. Press down on the cover slip to clear out any air bubbles. Put the slide on the microscope, use the low power (lOx) objective lens, and set the light where it is best for you. Focus the microscope and draw what you observe. To focus: look for small, irregularly shaped objects and turn the adjustment knob until the objects are clear. The iodine-water solution will stain the cells so they are more easily seen. Identify as many parts of the cheek cell as you can, and label them on your drawing. You should be able to see the cell membrane, cytoplasm, and nucleus. Carefully change to the high power (40x) objective lens, adjust the light setting and refocus on the cheek cell. Draw and label what you see on high power. Safety Precautions: Iodine will stain clothing and skin. Microscope slides and cover slips are usually glass so they must be handled carefully. When using the toothpicks to scrape the inside lining of the cheek, caution the students to scrape lightly and only two or three times. The students tend to scrape too hard and can injure the inside of their cheeks. All toothpicks should be immediately discarded after use. Ideas for other projects: Look at prepared microscope slides that show a variety of animal and plant cells and tissues.
Assessment:	This activity may be assessed using the following strategies: The "L" section of the class K-W-L on cells can be completed as a class. Students' data sheets can be evaluated using a rubric. Group discussions of observations on using the microscope and sharing their diagrams and findings with the other groups. Journal entries about observations and experiences using the microscopes to observe human cheek cells.
Attachment:	Observing Human Cheek Cells:Data Sheet

Part Two: Animal Cell Models
Materials:	The materials listed are based on students working in groups to build the cell models. If you prefer to have individual students make their own models, modify the quantities as needed. Some teachers have students provide their own materials to use when building the models so each model will be unique. Small zip-loc bags (I per group) Marbles or large nuts in shells (1 per group) Small black beans or poppy seeds (10 per group) Split green peas (8 per group) Animal cell model information sheet (attached) "Animal Cell Structure and Function" two-column assessment sheet (attached)
Procedure:	Ask the students review the three parts of an animal cell they observed in part one (cell membrane, cytoplasm, and nucleus). Create a graphic organizer as you discuss the animal cell organelles (structures) and their functions a. Cell membrane a thin membrane that controls what goes into and out of the cell b. Cytoplasm - a jelly-like material that contains the other organelles c. Endoplasmic reticulum (rough and smooth) - roadways that connect the nuclear membrane to the cell membrane, moves proteins and lipids through the cell d. Lysosomes - small sacs that release digestive enzymes to break down food particles for the cell's use e. Mitochondria - the cell's powerhouses that release a constant supply of energy (ATP) so the cell's parts can do their jobs f. Nucleus - controls the life activities of the cell g. Ribosomes - factories that build proteins out of amino acids (proteins are needed to repair and replace cell parts) Divide the class into groups and distribute the materials. Tell the groups they will be constructing a model of an animal cell and will use the materials to represent the different organelles typically found within animal cells. Distribute the "Animal Cell Model" information sheets to each student. When all of the models have been completed, each group should make a class presentation of their model.
Assessment:	This activity may be assessed using the following strategies: Cell models can be evaluated using a rubric. Class presentations can be evaluated using a rubric. The attached two-column chart, "Animal Cell Structure and Function" can be completed as a class project. Journal entries or a letter written to an animal from the cell's point of view. The letter should convince the animal of the cell's importance to its life.
Attachments:	Animal Cell Models: Student Information Sheet Animal Cell Structure and Function

Part Three: Plant Cell Models
Materials:	The materials listed are based on students working in groups to build the cell models. If you prefer to have individual students make their own models, modify the quantifies as needed. Some teachers have students provide their own materials to use when building the models so each model will be unique. Food storage container with cover - large enough to put the zip-loc bag in (1 per group) Small zip-loc bags (1 per group) Marbles or large nuts in shells (1 per group) Small black beans or poppy seeds (10 per group) Black-eyed peas (8 per group) Cooked spaghetti (8 per group) Split green peas (8 per group) Large lima beans (8 per group) Gelatin (enough to put some in each group's models) Plant cell model information sheet (attached) Hot plate and pan of water (to make gelatin) Note: You will also need access to a refrigerator
Procedures:	Ask students to review the parts of an animal cell they observed in Part Two. Adding to the graphic organizer created in part two, discuss the organelles in plant cells that are not found in animal cells: a. Cell wall - a tough, rigid outer covering that protects a plant cell and helps it maintain its shape b. Chloroplasts - structures that enable the plant to make sugars through photosynthesis c. Large central vacuoles - fluid-filled spaces surrounded by membranes; absorb water, may store proteins and the waste products of metabolism Divide the class into groups and distribute the materials. Tell the groups they will be constructing a model of a plant cell and will use the materials to represent the different organelles typically found within plant cells. Distribute the "Plant Cell Model" information sheets to each student. When all of the models have been completed, ask each group to present its model to the class. To illustrate the strength of the plant cell walls, ask groups to stack their models to form a "plant stem." Ideas for other projects: Make edible cell models using jawbreakers, jelly beans, shoestring licorice, gummy worms, sprinkles and gelatin. Put the candies in a zip-loc bag, make the gelatin and put it in the bag and seal, then lay the bag on its side in refrigerator. As the gelatin sets, squish the bag with your fingers to move the organelles into their proper places.
Assessment:	This activity may be assessed using the following strategies: Cell models can be evaluated using a rubric. Class presentations can be evaluated using a rubric. Each group can do a large Venn Diagram on plant and animal cells. Display completed Venn Diagrams around room and discuss. The "Animal Cell Structure and Function" chart done in Part Two can be modified by adding the three additional organelles present in plant cells. The "L" section of the class K-W-L on cells done in Part One can be completed by the class.
Attachment:	Plant Cell Models: Student Information Sheet

Observing Human Cheek Cells
Data Sheet
	Your prediction of how the cheek cell will look under the microscope
Low Power: Light Setting:		High Power: Light Setting:

ANIMAL CELL STRUCTURE AND FUNCTION
Structure	Function
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