Chapter 3 Cell Processes and Energy Name: Teacher: Hour: 1
Unit: Cell Processes and Energy Unit Completion Date: Vocabulary and Big Ideas Photosynthesis photosynthesis autotroph heterotroph chlorophyll Cellular Respiration cellular respiration fermentation Long-term I Can Statements Photosynthesis I can Date done Activity to support...explain how living things get energy from the sun....describe what happens during photosynthesis. identify the reactants and products of the photosynthetic equation. Cellular Respiration I can Date done Activity to support explain what happens during cellular respiration. identify the reactants and products of cellular respiration. explain the difference between photosynthesis and cellular respiration. understand fermentation. 2
Photosynthesis Understanding Main Ideas Fill in the blanks in the photosynthesis equation below with the names of the missing elements or compounds. Then answer the questions that follow. 1. + 2. + light energy 3. + 4. 5. What are the raw materials of photosynthesis? 6. What are the products of photosynthesis? 7. Why is light energy written on the left side of the equation? 8. Where does photosynthesis generally occur? Building Vocabulary Fill in the blank to complete each statement. 9. The process by which a cell captures the energy of sunlight and uses it to make food is called. 10. are colored chemical compounds that absorb light. 11. The main pigment found in the chloroplasts of plants is. 12. An organism that makes its own food is a(n). 13. A(n) is an organism that cannot make its own food. 14. One sugar produced by photosynthesis is. 3
Photosynthesis Read the passage and study the bar graph. Then answer the questions that follow. Chlorophyll and the Color of Light A pigment is a colored chemical compound that absorbs light. You can think of a pigment as a kind of sponge that absorbs light of all colors except the ones that it transmits and reflects. The colors that you see are the colors of light that the pigment reflects. The bar graph below shows the percentages of light of different colors that are reflected by the plant pigment chlorophyll. 1. Which color of light does chlorophyll reflect most? About what percent of light of this color does chlorophyll reflect? 2. Which color of light does chlorophyll absorb most? About what percent of light of this color does chlorophyll absorb? 3. The colors that are reflected less than 50% contribute very little to what the eye sees. Which colors does your eye respond to when you look at a green leaf? 4. Which colors of light do you not see when you look at a green leaf? 5. Explain in your own words how chlorophyll makes a leaf look green. 4
Cellular Respiration Understanding Main Ideas Fill in the blanks in the table below. Cellular Respiration Raw Materials Products Glucose 1. 2. Water 3. Answer the following questions in the spaces provided. 4. Where in the cell does the first stage of cellular respiration take place? 5. Where in the cell does the second stage of cellular respiration take place? Building Vocabulary Answer the following questions on a separate sheet of paper. 6. Why are cellular respiration and photosynthesis opposite processes? 5
Exhaling Carbon Dioxide Reviewing Content Cellular respiration is a process that occurs in the cells of most living organisms. The cells break down glucose in the presence of oxygen and release energy. Your cells get the oxygen necessary for cellular respiration from the air you breathe into your lungs. From the lungs, oxygen enters the bloodstream and is carried to all the cells in your body. The cells carry out cellular respiration, producing carbon dioxide and water and releasing energy. The carbon dioxide leaves the cells and travels via your blood to the lungs, where you exhale it. Your body uses the energy produced during cellular respiration to carry out life processes and activities. In this activity, you will investigate the relationship between exercise and the amount of carbon dioxide you exhale. Reviewing Inquiry Focus Most experiments have a manipulated variable and a responding variable. The manipulated variable is the factor that the experimenter purposely changes to test a hypothesis. The responding variable is the factor that changes as a result. Other variables must be controlled to allow you to eliminate other explanations for the experimental results. A scientist investigates the effect of fertilizer on plant growth. The experiment includes two plants in two different pots. One plant gets fertilizer; the other plant does not. The scientist measures how much the plants grow to determine the effect of the fertilizer. Lab Investigation In the chemical formula for glucose C 6 H 12 O 6, the letters tell you the elements in the molecule and the numbers indicate the number of atoms of each element. So, the glucose molecule has 6 carbon, 12 hydrogen, and 6 oxygen atoms. No number means 1 atom. In a chemical equation, the number before the molecule tells you how many molecules are in the reaction. Again, no number means 1. For example, in the equation below, there are 6 oxygen molecules (O 2 ). The number of oxygen atoms in the O 2 molecules equals the number of molecules multiplied by the number of atoms, or 6 2 = 12. For a chemical equation to be balanced, the total number of atoms of each element must be the same on both sides of the arrow. Count the number of atoms of each element on each side of the arrow. Is this equation balanced? C 6 H 12 O 6 + 6 O 2 6CO 2 + 6 H 2 O What is the manipulated variable? What is the responding variable? Name at least three factors the scientist needs to control to make sure the results are due to differences in fertilizer and not some other factor. 6
Name Date Exhaling Carbon Dioxide Problem INQUIRY FOCUS Control Variables, Predict Materials 2 150-mL beakers bromothymol blue (0.1% solution) 2 straws stopwatch or watch with second hand graduated cylinder, 25-mL paper towels grease pencil Is there a relationship between exercise and the amount of carbon dioxide you exhale? Procedure Part 1: Testing for Carbon Dioxide 1. Put on safety goggles, gloves, and lab apron. 2. Label one beaker Beaker 1 and the other beaker Beaker 2. Beaker 1 will be the control in the experiment. 3. Bromothymol blue can be used to test for the presence of carbon dioxide. Measure and pour 15 ml of bromothymol solution into each beaker. CAUTION: Bromothymol blue can stain skin and clothing. Avoid spilling or splashing it on yourself or others. 4. Observe and record the color of the solution in both beakers. 5. Place a straw in Beaker 2. As your partner keeps track of the time, gently blow through the straw into the solution until the solution changes color. CAUTION: Use the straw to breathe out only. Do not inhale or suck the solution back through the straw. Your partner should begin timing when you first blow through the straw and stop as soon as the solution changes color. Record in the data table the time it takes for the color to change. Part 2: Exercise and Carbon Dioxide 6. In Part 1, you timed the change of color without exercising beforehand by blowing into the beaker. Predict how long it will take the solution to change color if you conduct the test after two types of exercise: walking for 5 minutes and jogging for 5 minutes. 7
EXHALING CARBON DIOXIDE continued Lab Investigation 7. Empty the beakers from Part 1, rinse them with water, then repeat Steps 3 and 4. 8. CAUTION: If you have a medical condition that limits your ability to exercise, do not take part in the exercise portion of this activity. In an area designated by your teacher, you or your partner should walk at an even pace for 5 minutes. At the end of 5 minutes, immediately proceed to Step 9. 9. Repeat Step 5, making sure that the person who walked is the same person who blows through the straw. Record the elapsed time in the data table. 10. Repeat Step 7. 11. CAUTION: If you have a medical condition that limits your ability to exercise, do not take part in the exercise portion of this activity. In an area designated by your teacher, you or your partner should jog at an even pace for 5 minutes. At the end of 5 minutes, immediately proceed to Step 12. 12. Repeat Step 5, making sure that the person who jogged is the person who blows through the straw. Record the elapsed time in the data table. 13. Empty and rinse your beakers for a final time. Wash your hands with soap and warm water. Data Table Elapsed Time for Bromothymol Blue Solution to Turn Color No Exercise Walking for 5 Minutes Jogging for 5 Minutes Beaker 1 Beaker 2 8
EXHALING CARBON DIOXIDE continued Lab Investigation Analyze and Conclude Control Variables In Part 2, what variables did you need to control? Explain how you controlled those variables. Predict Was your prediction accurate? Explain. Measure How long did it take for the solution to change color the first time you did the test (without exercising)? Interpret Data How did exercising affect the amount of time it took for the solution to change color? Draw Conclusions What is the relationship between exercise and the amount of carbon dioxide exhaled? 9
Lab Investigation Exhaling Carbon Dioxide Interpret Data Compare your results with the results of several other groups in your class. How can you account for any similarities or differences? Design an Experiment What kind of relationship would you expect to exist between heart rate and carbon dioxide production? Design an experiment to test your hypothesis. Summarize Describe what you learned in this lab about the relationship between carbon dioxide and exercise, and explain what questions you still have. What I learned What I still want to know Analyze Experimental Results Plan a presentation that relates the results of your experiment to the process of cellular respiration. Be sure to explain how increased cellular activity affects carbon dioxide output. 10
Cellular Respiration Read the passage. Then answer the questions that follow. History of Fermentation In 1854, the French chemist Louis Pasteur determined that fermentation is caused by yeast. His work was influenced by the earlier work of Theodor Schwann, the German scientist who helped develop the cell theory. Around 1840, Schwann concluded that fermentation is the result of processes that occur in living things. In 1907, a German chemist named Eduard Buchner received the Nobel prize for showing that enzymes in yeast cells cause fermentation. About two decades later, two other scientists determined exactly how enzymes cause fermentation. Their names are Arthur Harden and Hans Euler-Chelpin, and they won the Nobel prize for their work in 1929. By the 1940s, technology was developed to use fermentation to produce antibiotics. Fermentation is a very useful process. Today it is used to produce industrial chemicals, medicines such as antibiotics, and alcoholic beverages, as well as to make bread rise and to preserve many types of food. Some of these uses have been known for thousands of years. For example, the Chinese used fermented soybean curd to treat skin infections 3,000 years ago, and they started using fermented tea to treat a variety of illnesses as early as 220 B.C. The use of fermentation to make bread rise and to produce alcoholic beverages is as old as the development of agriculture itself, which most scholars date to about 8000 B.C. 1. Use the information provided in the passage above to make a timeline of the history of fermentation. 2. What contribution did Louis Pasteur make to the understanding of the process of fermentation? 3. What are two of the oldest uses of fermentation? 4. How is fermentation used in medicine today? 11