What is Cellular Respiration?
Cells need energy to function. Cellular respiration is the process cells — plant cells and animal cells — use to make this energy. Make sure your students understand that the cells employ oxygen to convert sugar into energy. Cellular respiration is necessary to turn the food that is consumed into energy in order for a cell to grow and thrive.
Photosynthesis Vs. Cellular Respiration
Students understand that photosynthesis is the way plants use energy from the sun to convert carbon dioxide and water into sugar, which makes food for the plant. In the classroom, cellular respiration is a logical follow-up lesson to learning about photosynthesis.
Draw a Venn diagram on the whiteboard, or interactive whiteboard, in order to compare and contrast photosynthesis and cellular respiration. These two processes that are important to the function of cells involve many of the same elements — carbon, hydrogen, oxygen. Completing the Venn diagram with the class will give them an understanding of the raw materials in both processes, waste materials in each process and the purpose of each process.
Drawing the Cycle
The waste products of photosynthesis are a portion of the raw materials of cellular respiration. The waste products of cellular respiration are two of
the raw materials for photosynthesis. On the interactive whiteboard arrange the terms involved in both photosynthesis and cellular respiration, along with a tree, an animal that is a herbivore and the sun. Have the students take turns moving the terms in sequential order on the whiteboard. They draw arrows showing the direction the cycles of photosynthesis and cellular respiration follow.
After the group whiteboard activity, ask the students to draw the cycle. They use themselves doing an activity that requires energy, releasing water through perspiration and carbon dioxide through breathing hard during their activity. Even though blinking requires energy, the drawings of the students snowboarding or skateboarding are more entertaining and engaging for the students. Encourage them to draw their favorite activity as a part of the cellular respiration cycle.
Putting It All Together
Represent the formula for cellular respiration on the board with cut-out circles to represent each atom of carbon, hydrogen and oxygen needed to perform cellular respiration. Also, represent the waste products of carbon, oxygen and water — hydrogen and oxygen. Represent the energy expended by having a cut-out of a stick figure doing jumping jacks. Review the formula with the students. Take every atom off of the board and hand each atom to a student. Ask the students to recreate the formula with the atoms. One at a time, they approach the board to adhere their atom to the proper location in the formula. Challenge the students to do it as quickly as possible and silently. It will soon be obvious the students that understand the process. For a final assignment, time the classmates recreating the formula.
- Think Central; Photosynthesis and Cellular Respiration, http://go.hrw.com/resources/go_sc/bpe/HX1QUZ05.PDF.
- Photosynthesis & Cellular Respiration Presentation, Mr. Rojas, http://www.rrojas.com/5/science/lifescience/photosynthesiscellularrespirationpresentation.
- Basic Venn Diagram, http://www.graphic.org/venbas.html
- Biology4Kids, http://www.biology4kids.com/files/plants_photosynthesis.html