Cell Respiration, part 1
Lesson 12 of 30
Objective: Students will be able to explain the cycling of energy through the process of cell respiration.
Warm-Up: Instruct students to examine the image. Ask, “In which step is energy released and made available for metabolic processes?”
This question serves as a formative assessment of students’ knowledge of previous lessons on cellular energy. It’s a good question because it requires students to interpret an image versus a typical word problem.
Expect some students to struggle with interpreting the image. Allow students to ponder the question for several seconds before instructing students to consider ATP as the starting point of the process being shown in the image. Allow student volunteers to interpret the image. Look for students to not only provide the correct response but also identify that energy is released when ATP releases a phosphate group. When conducting this type of review at the start of class, I like to question, observe, respond (and review) then move to a higher ordered question. I continue with this cycle until I possess a clear picture of how well students comprehend previously taught content. For example, "So, when ATP loses a phosphate group, what molecule is formed and how many phosphate groups does it have?
Once it’s apparent that students understand the image, inform them the diagram represents part of the process of cellular respiration. Tell students that in today’s lesson, we will learn about the process of cellular respiration.
Introduce New Material
Ask students, “In what organelle of the cell does the process of cellular respiration occur?” Students should be able to recall the correct response from the lesson on cell organelles. As a practice, relate new content to previously taught material. This practice help students connect seemingly disparate chunks of information from former lessons so that they will understand that the daily content relates in pieces to a whole conceptual understanding of biology like pieces of a puzzle relate to the creation of a picture. Listen to students’ responses and emphasize that cellular respiration occurs in the mitochondria of the cell.
Introduce new vocabulary: cellular respiration, anaerobic, aerobic, fermentation, glycolysis, lactic acid, Krebs Cycle(Citric Acid Cycle), electron transport chain. Instruct students to add the bolded terms with Greek or Latin roots, prefixes or suffixes to their vocabulary maps.
Once it is affirmed that students know where cell respiration occurs, introduce content related to the process of cellular respiration, providing information to students verbally and visually, using a LCD projector. Instruct students to follow the instruction using guided notes or a note- taking format that has been previously taught. Relate the process of cellular respiration to photosynthesis by showing students how the processes are the reverse of one another.
During the instruction, be sure to address these common misconceptions:
- Only animals carry out respiration.
- Plants create energy.
- Energy comes directly from food.
Emphasize that food must be converted into energy by both plants (that make their own food) and animals. This reason is why both plants and animals carry our respiration.
Show a brief video clip, Cellular Respiration that can be downloaded from the Discovery Channel. The clip reinforces the high level concepts that have been presented. Strategically placed video clips in instruction can serve as a, effective “pause” that allows students to digest the information while listening to a re-cap of what was just shared.
Detail the three cycles of respiration and the number of ATP produced in each of the cycles.
When discussing glycolysis, allow students an opportunity to dissect the term into its word parts to tell you what they think the word means. Look for students to recall that “lyse” means to spit or break as they learned with lysosomes and hydrolysis. Before telling students the meaning of the term, ask them to consider what term might be related to “glyco” based on how it sounds? Look for students to identify that the term, glucose might be related. This process of “dissection” of a new term helps them practice using what they know about parts of a term to infer its meaning. Show them how they can infer that the meaning of the term, glycolysis means the breakdown of glucose, using the word parts that they know.
Inform students that they will complete a “gizmo” today on the Cell Energy cycle, using the Explore Learning technology called gizmos. Gizmos are computer simulations that help students see science in action.
Issue the computers so that students have them before you model use of the site for the lesson. Instruct them to log in and access the main site.
Note: Explore Learning is an inquiry-based learning system using online simulations. My school district subscribed to the service a couple of years ago and I have found the lessons to be highly effective in helping my students grasp science concepts. Sign up for a free trial if you are interested in accessing the resources and student exploration worksheet associated with this lesson.
Walk around to monitor that all students are on task, able to access the site and log in with their individual user names. Identify 2-4 students who are skilled computer users and utilize them as a resource to assist other students who are not. Once it is determined that all students have accessed the site, model how to access the lesson and navigate the gizmo. Instruct students to watch and perform each action that you take, using the computers they have at their desks.
Decide beforehand if you will provide copies of the worksheet or if students will complete and submit electronic worksheets. Some students work best with hard copies so make the determination in advance of who will need a hard copy and have copies available for those students. If you decide that students can complete the assignment online, model how to download a “word” copy, type their answers onto the worksheet and submit the assignment electronically.
Point out the vocabulary that is associated with the lesson and answer the “Prior Knowledge Question” as a class, taking responses from 1-3 students to develop an answer for the class. This allows you to hear students’ reasoning, as a formative assessment and it allows everyone to start at the same point once you release them to work independently. If students struggle with the question, spiral back and reinforce key concepts before proceeding.
Model 1-2 of the gizmo warm-up activities for the class. The gizmo warm-up is intended to help students learn how to navigate the controls for the lesson that follows. As you complete each action, instruct students to use their computers to perform the same action. Release students to complete the warm-up activity as you walk around to ensure that everyone is able to navigate the controls for the lesson.
Instruct students to work independently on the computers to complete Activites B and C of the Cell Energy cycle gizmo and the assessment that follows the simulation. Because students have already learned photosynthesis, it may not be necessary to have them complete part A.
Instruct students to drop the completed gizmo in Edmodo when they complete the assignment or instruct students to complete a hard copy that you provide. Based on students’ particular learning needs and abilities, determine which students will submit electronically and which will not.
Note: Edmodo is a great teacher website that allows teachers to load assignments, send reminders and schedule important dates for students and their parent/guardian to access outside of class. Students join a class that is set up by the teacher and are then able to submit assignments directly to the site. Edmodo also allows students to take quizzes and engage in topic-based chats, as well.
Submission of this assignment electronically serves two purposes. First, utilizing Edmodo helps students learn how to attach and send files electronically. By submitting assignments through Edmodo, students learn how to upload files (a skill they will need as they advance in their high school classes). Second, electronic submission of assignments saves a lot of paper and reduces the amount of time needed to make copies of a multi-page document.
Alternatives to electronic submission include, instructing students to send the completed assignment to a designated email address. If computers are not available in the school setting, instruct students to access a computer outside of class (a local library) to complete the assignment. A lack of computers in the school setting should not be a deterrent to students’ use of technology. Encourage students to utilize available resources in the community (libraries) to enhance their technological skills and abilities.
After the completed assignments are received, look for students’ ability to reason and draw a correct conclusion about how photosynthesis and cellular respiration are related. The student work sample shows that the student was able to make observations and respond correctly to the questions. The student was also able to explain how photosynthesis and cell respiration are related.
Engage students in a closing discussion of this question, “Can you explain why the activity was called the Cell Energy cycle?” Direct students to consider how are animals and plants dependent on one another as they formulate a response to the question.
Look for students to identify that animals produce carbon dioxide as a product of respiration which is needed by plants to perform photosynthesis. Let students know that they will examine the production of carbon dioxide further in the next lesson, cell respiration, part 2.