Cellular Respiration: Virtual Lab
※ Download: Cellular respiration virtual lab answer key
In order to make sure that there is only one variable being tested, it is key that the students control all other variables. The Elodea releases O 2 when it carries out photosynthesis; this turns the solution blue because it is basic. To calculate this, it is easiest to find the change in y at 10 minutes 0.
A respirometer is the system used to measure cellular respiration. The middle is after 2 days green and the jar on the right is after 5 days yellow. Check their hypotheses to see if students understand the concept of using bromothymol blue solution as an indicator of photosynthesis and respiration.
Cellular Respiration: Virtual Lab - Have students follow the procedure for the four test tubes and fill out the Design Table on the lab handout.
In this lesson, students compare the basic energy transfer in photosynthesis and cell respiration, with a focus on the role of ATP. Aerobic, or oxidative, respiration requires oxygen; anaerobic respiration does not require oxygen. Collect and assess the Photosynthesis The Light and Calvin Reactions chart and the exit tickets. Collect and assess the Cell Respiration Worksheet. Check their hypotheses to see if students understand the concept of using bromothymol blue solution as an indicator of photosynthesis and respiration. Collect and assess the lab worksheet. Scaffolding, Active Engagement, Explicit Instruction : This is a lesson on the complementary processes of photosynthesis and cell respiration. The focus is on the overall energy transfer in each process, as well as the roles of the chloroplast, mitochondria, and ATP. Students discuss why plants need sunlight, and then compare the basic needs of plants and animals. Several suggestions are provided in the Extension section. Photosynthesis and cell respiration are presented separately, and then the lab requires students to synthesize the concepts from both processes. Place the plant in the sun for several days. Make a chart on board, such as the one below, and have students help you fill it in. Tell students that plants and animals on Earth are interdependent. Tell students that this lesson is all about the energy exchange between plants and animals in the processes of photosynthesis and cell respiration, and that the lesson will focus on photosynthesis. Explain that the simplest way to explain photosynthesis is that it is the process of making energy from light. Have students point out where on the house plant photosynthesis takes place. Show students the images in Internal Structure of a Chloroplast and point out the stroma, thylakoids, and grana. If you have a microscope with a projector, this is a good time to show students actual magnified leaf cells and point out the chloroplasts. Optional Demonstration Fill a beaker or plastic cup about halfway with sodium bicarbonate solution a source of carbon dioxide. Place a sprig of an Elodea plant into a large test tube with the cut stem at the bottom. Fill the test tube with sodium bicarbonate solution. Holding your thumb over the mouth of the test tube, turn it upside down and lower it carefully into the beaker. Make sure there is no air trapped in the tube. Have students observe the setup carefully and describe what they see. Place the cup in bright sunlight. Leave it for at least 20 minutes, and then show it to students again. They should see bubbles of gas around the Elodea leaves. Remind students that photosynthesis produces sugars and oxygen, and because sugars are not gases, this must be oxygen gas. Oxygen is a waste product of photosynthesis because it is released from the plant into the environment. Guided Practice Hand out copies of Photosynthesis The Light and Calvin Reactions. Write the equation for photosynthesis on the board and have students write it on the worksheet, and have them write the equation in sentence form. Show students the diagram of the reactions using Reactions of Photosynthesis. Describe the light-dependent reaction and the Calvin cycle using the diagram, and have students take notes in the chart on the worksheet. Be sure to explain the roles of ATP chemical compound that living things use to store and release energy and NADP + carrier molecule that transfers high-energy electrons from chlorophyll to chemical reactions in other parts of the cell in the reactions. Exit Ticket: Describe the role of ATP in the process of photosynthesis. Day 2: Cell Respiration Mini-Lesson: Have students take notes as you explain cell respiration. Explain that overall, photosynthesis and cell respiration are opposite processes. Remind students that photosynthesis converts sunlight energy into glucose and other high-energy sugars, which in turn serve as food for other organisms. In aerobic oxidative respiration, both plants and animals convert the glucose back into energy for growth and other life processes. The chemical equation for respiration shows that glucose is combined with oxygen to release energy. C 6H 12O 6 + 6O 2 6CO 2 + 6H 2O + energy Respiration is the breaking down of glucose for energy to grow and carry out other life processes metabolism. It is important to emphasize that respiration takes place in the cells of both plants and animals. Have students recall what they know about the structure and function of the mitochondria from Lesson 1. Explain that there are three major cycles in cell respiration: glycolysis, the citric acid or Krebs cycle, and the electron transport chain. For guided practice, show students the Overview of Cell Respiration. CO 2 Have students copy the diagram in their notes and label each stage, as well as the reactants and products. For independent practice, have students complete the Cell Respiration worksheet. Days 3—4: Comparing Photosynthesis and Cell Respiration To prepare, obtain Elodea and aquatic organisms. These can be ordered through a biological supply company, such as Carolina Biological Supply, or obtained at a local aquarium store. See related resources below. Lab Activity CAUTION: Make sure that students wear safety goggles during the entire lab. Have them follow the procedure to set up the lab, and then fill in the Design table. They should leave the experimental setup for at least an hour; overnight is preferable. Have students work in groups of 3—4 to design an experiment on the relationship between photosynthesis and respiration, using the questions shown on the Photosynthesis and Respiration Lab worksheet. First, they should develop a hypothesis for each question and fill in the Develop a Hypothesis table on the worksheet. Explain that in order to test their hypotheses, they can use an acid-base indicator called Bromothymol blue solution. Show them the Bromothymol Blue Color Change and have them copy the sentences from the resource into their notes, filling in the blanks. Bromothymol blue shows the presence of carbon dioxide by turning yellow, because carbon dioxide creates an acidic solution i. In low levels of carbon dioxide, the solution will appear blue. Acid CO 2 present Neutral Base Yellow Blue-green Blue Describe the experimental procedure from the lab handout as you demonstrate it step by step. Have students follow the procedure for the four test tubes and fill out the Design Table on the lab handout. While students are waiting, have them complete the independent practice: Students work individually to complete the Comparison of Photosynthesis and Cell Respiration chart and the Photosynthesis and Respiration: Plant Diagram. Have students observe the changes in each of the test tubes, and write their observations and conclusions. Have them clean up all lab materials. Discuss their conclusions as a whole class. The Elodea releases O 2 when it carries out photosynthesis; this turns the solution blue because it is basic. The solution in the test tube with the snail and Elodea does not change because the processes of photosynthesis and respiration balance each other out. Conclude the lesson with a discussion of the overall energy transfer that occurs between photosynthesis and respiration. Have them arrange the index cards to show the process of photosynthesis, and then rearrange them to show the process of cell respiration, to reinforce that the processes are complementary. Create a flowchart for the steps of one of the processes.
While my students are familiar with this, you could introduce the idea that in science it is important to be able to to track energy and matter as it flows into and out of systems. Glucose may be oxidized completely if an adequate amount of oxygen is present. Water enters the pipette for a short distance and stops. Respiration: Lab Quiz Answers Cell Respiration: Lab Quiz Answers The accompanying graph shows results from an experiment done to measure cellular respiration in germinating and nongerminating corn seeds. We can think, plan, and recall events that have happened in and around our lives. Carry out your procedure.
