4. Seeing Cells - Lesson Plan
- Ask students to free associate what comes to mind when you write the word “cell”. In addition to biological cells, they may come up with prison cells, cell phones, a terrorist cell and more. In all these uses, a “cell” is a single functioning unit or compartment that is part of a larger whole. That too is what a cell is in biological terms, the building block upon which all living things are built.
- Show students pictures of cells. Have students tell you what they see and notice. Emphasize both the diversity of different cell shapes and sizes and also how all cells share certain features.
- Give students the cell coloring diagrams. Lead your students in coloring the diagrams and describe the job of each cell part as you go. You may want to have students write the job of each part of the cell beside the name of the part.
- Now that students have learned a little bit about cells, they will now get a chance to look at some real cells through a microscope. If students have not used a microscope before, go over the parts of a microscope and how to properly use it.
- Demonstrate how to make each type of slide (see the directions on the Seeing Cells student handout, one of the attachments at the bottom of the main summary page).
- Answer any questions then let students begin work on the lab in groups of two. By the end of the activity, students should have 2 labeled drawings of each type of cell, one at 40x and one at 400x.
- Assist students with making slides, using the microscopes, and bringing cells into focus. The human cheek cells are often difficult to find and get into focus since they are much smaller and more disperse than the onion and Elodea cells. Many will need help locating these cells on the slide.
- When all student have completed the drawings, review what they saw using the Cell Images transparency.
- Point out the cell parts that can be seen through a light microscope (cell membrane, cell wall, cytoplasm, nucleus, and chloroplasts).
- Discuss why it is that other cell parts could not be readily observed (they are too small or need special dyes to be able to see them).
- Discuss the differences between plant and animal cells (plants have cell walls and chloroplasts) as well as the difference between the elodea and onion skin cells (only leaf cells have chloroplasts).