Lesson 9 S

9.1 How Do Food Molecules Provide My Cells with Energy July 22, 2012Footer text here2

Prompts for Partners Think about the chemical reaction for burning oil. What evidence do you have that a similar chemical reaction happened in your body during Lesson 1 when you were exercising? July 22, 2012Footer text here3

Background Knowledge You have some evidence that a chemical reaction similar to burning is happening in your bodies. This chemical reaction is called cellular respiration. Where is energy needed inside of your body? What is the heart (or brain or muscle) made of? What is happening in each cell of this organ that needs energy? Are there any cells in the heart, brain, or muscle that do not need energy? Since every cell needs energy, you will have to have evidence that the reactants of the chemical reaction that converts energy from food can get to all 100 trillion cells of the body. July 22, 2012Footer text here4

Review What are the reactants in the chemical reaction for burning food molecules? How do you and all other animals get food molecules? July 22, 2012Footer text here5

Review of Burning and Chewing What happens first to a cracker when you eat it? What is your evidence? What happens when the carbohydrate subunits leave your mouth? Does the body now have energy because the starch has broken down into carbohydrate subunits? July 22, 2012Footer text here6

Capillary : How can you use this image to explain how the carbohydrate subunits leave the small intestine? July 22, 2012Footer text here7

Circulatory System What are capillaries? What system of the body are they part of? What is the function of the capillary system? How can you use this model of the circulatory system to explain how carbohydrate subunits get from the small intestine to every cell of the body? July 22, 2012Footer text here8

Using Fats Food can be used immediately or stored for later. If these carbohydrate subunits are stored for later, they can be changed into fat via a chemical reaction. When the cells of the body need energy, other chemical reactions can change fat into a molecule the body can use for cellular respiration July 22, 2012Footer text here9

Respiratory System How can you use this model of the respiratory system to explain how oxygen gets into the body? July 22, 2012Footer text here10

Gas Exchange How can you use this model to explain how oxygen leaves the lungs and gets to every cell of the body? From your investigation burning oil, what are the cells of the body using oxygen to do? What are the products of burning food? July 22, 2012Footer text here11

Capillary and Small Intestine/Circulatory System July 22, 2012Footer text here12 Explain how the carbon dioxide that is produced by every cell of the body leaves the body. Based on your investigation of burning food, why is carbon dioxide being produced by the cells of the body?

Looking at Data Chart on IQWST 9.1 How many people do you think doctors took measurements from to get these numbers? Why is this important? July 22, 2012Footer text here13

Part 2 Researchers set up an experiment to test the amount of glucose present in the blood in three blood vessels. Scientists had dogs drink a glucose solution and then measured the amount of glucose in their blood every 15 minutes. The cells use glucose because blood going to the cells of the body from the liver has a higher concentration of glucose than blood coming back to the digestive system from the cells of the body. July 22, 2012Footer text here14

Cellular Respiration You have only gathered evidence that the cells use glucose for cellular respiration. Protein and fat molecules can also be used. All food molecules can be used for energy. A balanced chemical reaction for burning requires water. Water must also be part of this chemical reaction. July 22, 2012Footer text here15

Cellular Respiration Formula July 22, 2012Footer text here16

Notes You now have evidence that this chemical reaction happens in the cells of animals (humans and dogs). Cellular respiration is similar to burning, and the purpose of this chemical reaction is to provide energy for organisms to do things. Can other organisms also use this chemical reaction to convert energy? How do food molecules provide plant cells with energy? Do you have any evidence that plant cells perform cellular respiration? In the next activity you will investigate if plants carry out cellular respiration July 22, 2012Footer text here17

Activity 9.2 How Do Food Molecules Provide Plants With Energy

Brainstorm Is it possible that plants perform cellular respiration? All of your evidence points to photosynthesis, and none points toward plants carrying out cellular respiration. However, many chemical reactions happen at the same time in all organisms. Think about the investigation with the elodea in which you measured the change in carbon dioxide using the BTB solution. How did the BTB change? Why?

Comparing Photosynthesis and Respiration July 22, 2012Footer text here20 Imagine that both of these chemical reactions— photosynthesis and cellular respiration—were happening at the same time in the elodea. Would you expect to see any change in the BTB color? Why? Do the data they collected about photosynthesis support this idea that it happens at the same time as cellular respiration? Why?

July 22, 2012Footer text here21 This time, imagine that twice as much photosynthesis was happening as cellular respiration. Would you expect to see any change in the BTB color? Why? Do the data they collected about photosynthesis support this idea that it happens at the same time as cellular respiration, but more photosynthesis happens than cellular respiration? Why?

Two Hypotheses Based on this experiment, students now have two hypotheses about how food molecules provide plants with energy. 1. Plants do not use cellular respiration (but they use another chemical reaction). 2. Plants do use cellular respiration, but it happens at a slower rate than photosynthesis, so it cannot be detected. IF the second hypothesis were true, you could detect cellular respiration if you could turn off photosynthesis If the first hypothesis were true, you could detect cellular respiration even if you could turn off photosynthesis July 22, 2012Footer text here22

Testing the Hypotheses Based on what you learned in Lesson 6 about photosynthesis, how can you turn off photosynthesis? Based on what you know about cellular respiration in animals, what evidence should you look for of cellular respiration for plants growing in the dark? You are going to use these same tests again, but this time you will perform them on plants that are in the dark. GO to Activity Sheet 9.2, and fill out the Prediction section. July 22, 2012Footer text here23

TESTING FOR CARBON DIOXIDE You are going to set up an example of the experiment that they did showing that plants use carbon dioxide in the light during photosynthesis. Place a sprig of elodea in one test tube and nothing in a second. Using a straw, blow into the beaker with 50mL BTB to turn it from blue to yellow. Pour the yellow BTB solution into the test tube to submerge the elodea. Pour the same quantity of yellow BTB into the second test tube. Stopper both test tubes and leave exposed to light overnight. What will the result of this experiment be? Why?” Record the color of the tubes you set up in the demonstration in the light and your own tubes that will be in the dark. July 22, 2012Footer text here24

TESTING FOR OXYGEN Conduct another investigation about the concentration of oxygen in plants growing in the dark. This will be similar to the investigation conducted in Lesson 7 using the dissolved oxygen probe to measure the change in oxygen dissolved in water while the elodea was undergoing photosynthesis “What were the results of this experiment with the elodea in the light? Why Turn photosynthesis off by placing the elodea in the dark. Place the oxygen sensor in the water and measure the change overnight. You will investigate the results of this experiment during the next class and evaluate your predictions based on the results. July 22, 2012Footer text here25

Notes: Plants do not use cellular respiration (but they do use another chemical reaction) to provide energy. Plants do use cellular respiration, but it happens at a slower rate than photosynthesis, so it cannot be detected in the light. July 22, 2012Footer text here26

Making Sense Part 1 What do the data suggest is happening to the concentration of carbon dioxide in the light? What chemical reaction does this provide evidence for? Explain. What do the data suggest is happening to the concentration of carbon dioxide in the dark? Explain Which of the hypotheses about cellular respiration in plants do these data support? Explain How would you expect the color of the BTB to change if plants do not carry out cellular respiration? How were the results of the investigation of the plant in the dark similar to when you exhaled into the BTB solution? What is the reason for this similarity July 22, 2012Footer text here27

Making Sense: Dissolved Oxygen Time Probe Reading(% dissolved oxygen) 9:52 AM24% 10:22 AM18% 10:52 AM17% 11:22 AM14% 11:52 AM13% AM13% 12:52 PM12% 1:22 PM11% 1:52 PM10% 2:22 PM7% 2:52 PM5% 3.22 PM2% 3:52 PM1% 4:22 PM1% 4:52 PM0% 5:22 PM0% 5:52 PM0% 6:22 PM0% 6:52 PM0% 7:22 PM0% 7:52 PM0% 8:22 PM0% 8:52 PM0% July 22, 2012Footer text here28 1) What do the data suggest is happening to the concentration of oxygen in the dark. 2) Which of the hypotheses about cellular respiration in plants do these data support? Explain. 3) How would you expect the concentration of the oxygen to change if plants do not carry out cellular respiration? 4) How is this similar to when you measured the oxygen concentration in your breath with the oxygen probe? 5) What is the reason for this similarity?

Making Sense: Part 3: Starch These leaves were going through the same chemical reactions as the elodea left overnight in the dark. Describe the setup for the geranium leaf experiment. What were the results? Before we covered the leaves, do you think that there was starch in the cells of all of the leaves? Why? What do the results of this experiment suggest happens to starch in plants when they are in the dark? Why? In Lesson 5, we found that large molecules like starch have to be broken down before they can be used for energy. What is starch broken down into? Which of the hypotheses about cellular respiration in plants do these data support? Explain. How would you expect the concentration of the glucose to change if plants do not carry out cellular respiration? How are the data from the geranium leaves in the dark similar to the data about the concentration of glucose in the blood in the dogs? July 22, 2012Footer text here29

What HAPPENS? July 22, 2012Footer text here30

Pulling it All Together Describe what you now know about cellular respiration and photosynthesis in plants based on what you have learned in this unit and this image. What organisms perform cellular respiration? What is the purpose of cellular respiration? Is there any time when animals are not performing cellular respiration? Plants? Why do your data not support the idea that plants perform cellular respiration in the light? Was cellular respiration happening in the elodea in the dark? What is your evidence? Was cellular respiration happening in the elodea in the light? What is your reasoning? In which of the test tubes was cellular respiration occurring overnight? What is your reasoning/evidence? July 22, 2012Footer text here31

Summarizing The Data Cellular respiration is the chemical reaction used to provide energy to the cells of an organism. This chemical reaction happens all the time in every cell. When organisms need more energy, they perform more cellular respiration. In animals, this means that the heart has to pump faster to bring food molecules and oxygen to the cells faster and carry away carbon dioxide faster. It also means that animals have to breathe faster to get more oxygen and get rid of more carbon dioxide. While the function of cellular respiration is providing energy, none of the data students analyzed in the last two activities has given them evidence of energy. In the next activity, they will gain a greater understanding of cellular respiration using models and investigate more about how this chemical reaction provides energy to cells. July 22, 2012Footer text here32

Graphic Organizers July 22, 2012Footer text here33

9.3 How Do Food Molecules Provide Energy July 22, 2012Footer text here34

Where do we see energy in the two processes? Cellular respiration can provide many types of energy to the cells of the body, but importantly kinetic and thermal energy are provided Importantly, the function of the chemical reaction is to provide organisms with energy to carry out various processes. Cellular respiration also provides kinetic energy for the body to do things. Energy can be provided in many types: kinetic, thermal, sound, and electrical. You have evidence for some of these types of energy in animals, but less evidence in plants. What are some of the examples of kinetic energy you observed during the exercise activity? INFRARED for thermal energy July 22, 2012Footer text here35

Scientific Principles Cellular respiration is the chemical reaction that provides energy to the cells of an organism. During cellular respiration, organisms (plants and animals) use oxygen and food molecules and produce water and carbon dioxide. July 22, 2012Footer text here36