Biology Commonwealth of Virginia
Organizing Topic — Life Functions and Processes
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Organizing Topic — Life Functions and ProcessesStandards of LearningBIO.1 The student will plan and conduct investigations in which a) observations of living organisms are recorded in the lab and in the field; b) hypotheses are formulated based on direct observations and information from scientific literature; c) variables are defined and investigations are designed to test hypotheses; d) graphing and arithmetic calculations are used as tools in data analysis; i) appropriate technology including computers, graphing calculators, and probeware, is used for gathering and analyzing data and communicating results. BIO.2 The student will investigate and understand the history of biological concepts. Key concepts include c) evidence supporting the germ theory of infectious disease. BIO.3 The student will investigate and understand the chemical and biochemical principles essential for life. Key concepts include d) the capture, storage, transformation, and flow of energy through the processes of photosynthesis and respiration. BIO.5 The student will investigate and understand life functions of archaebacteria, monerans (eubacteria), protists, fungi, plants, and animals including humans. Key concepts include d) maintenance of homeostasis; e) human health issues, human anatomy, body systems, and life functions. Essential Understandings, Correlation to Textbooks andKnowledge, and Skills Other Instructional MaterialsThe student will use hands-on investigations, problem solving activities, scientific communication, and scientific reasoning to generalize the following regarding energy processes: Plant cells and many microorganisms use solar energy to combine molecules of carbon dioxide and water into complex, energy-rich organic molecules and release oxygen into the environment. The process of photosynthesis provides a vital connection between the sun and the energy needs of living things. The breakdown of nutrient molecules enables all cells to utilize energy stored in specific chemicals to carry out the life functions of the cell. Photosynthesis and cell respiration are complementary processes for cycling carbon dioxide and oxygen in ecosystems. Light is the initial source of energy for most communities. relate plant structures and functions to process of photosynthesis and respiration; illustrate and describe the energy conversions that occur during photosynthesis and respiration; summarize the process of photosynthesis, including the following: Cells trap energy from sunlight with chlorophyll, and use the energy, carbon dioxide, and water to produce energy-rich organic molecules and oxygen. Photosynthesis involves an energy conversion in which light energy is converted to chemical energy in specialized cells (e.g., plants and some protists). summarize the processes of cells, including the following: Eukaryotic cells (plant and animals) burn organic molecules with oxygen to produce energy, carbon dioxide, and water. Cells release the chemical energy stored in the products of photosynthesis. This energy is transported in molecules of ATP. When cells need energy to do work, certain enzymes release the energy stored in the chemical bonds in ATP. recognize the equations for photosynthesis and respiration and identify the reactants and products for both; recognize that many organisms, including human beings, are composed of groups of cells (tissues, organs, and systems) that are specialized to provide the organism with the basic requirements of life: obtaining food and deriving energy from it, maintaining homeostasis, coordinating body functions, communicating between cells, and reproducing; explain the purpose and functioning of the following human systems: Digestive Respiratory Circulatory Excretory Immune Nervous Endocrine Skeletal Integumentary; discuss the major factors that impact human health, including genetic predispositions microorganisms environmental influences; recognize that the acceptance of the germ theory of disease has resulted in a modern emphasis on sanitation, including safe handling of food and water aseptic techniques development of vaccines chemicals and processes to destroy microorganisms. Photosynthesis and RespirationOrganizing Topic Life Functions and Processes Overview Students discover how to test a hypothesis, using living organisms. They design a controlled experiment and predict the outcome. They see the change in the bromthymol blue indicator color that signals the production of oxygen or carbon dioxide. (Students should have some background in pH levels and acidic and basic solutions before undertaking this activity.) Related Standards of Learning BIO.1a, b, c; BIO.3d ObjectivesThe students will generalize the following regarding energy processes: Plant cells and many microorganisms use solar energy to combine molecules of carbon dioxide and water into complex, energy-rich organic molecules and release oxygen into the environment. The process of photosynthesis provides a vital connection between the sun and the energy needs of living things. The breakdown of nutrient molecules enables all cells to utilize energy stored in specific chemicals to carry out the life functions of the cell. Photosynthesis and cell respiration are complementary processes for cycling carbon dioxide and oxygen in ecosystems. Light is the initial source of energy for most communities. relate plant structures and functions to process of photosynthesis and respiration; illustrate and describe the energy conversions that occur during photosynthesis and respiration; summarize the process of photosynthesis, including the following: Cells trap energy form sunlight with chlorophyll, and use the energy, carbon dioxide, and water to produce energy-rich organic molecules and oxygen. Photosynthesis involves an energy conversion in which light energy is converted to chemical energy in specialized cells (e.g., plants and some protists). Materials neededFor each lab group: Containers with lids (test tubes or even zip-top baggies) Pond or aquarium water Bromthymol blue solution, 4% Elodea (or other aquarium plants) Small water snails or other pond critters, such as guppies or daphnia Light source Copies of the attached student data sheet Instructional activityContent/Teacher Notes“The Elodea and the Snail” is a classic lab activity on planning and conducting investigations, in which students use living organisms to learn about photosynthesis and respiration. The time required to detect results is several hours. This lesson can be used either at the beginning of the year to demonstrate the scientific method and experimental design or later in the year to demonstrate the interdependence of photosynthesis and respiration. A  primary difference between plants and animals is the plant’s ability to manufacture its own food. Green plants absorb water and carbon dioxide from the environment and, utilizing energy from the sun, turn these simple substances into energy-rich glucose (carbohydrates — sugars and starches) and oxygen. This process is called “photosynthesis” (meaning literally “to put together with light”) and is the cornerstone of life on Earth.
In photosynthesis, the sun’s energy combines the hydrogen from water (H20) with carbon dioxide (CO2), producing glucose (C6H12O6) and oxygen (O2), which is given off as a by-product. The chemical equation for the process of photosynthesis is: 6CO2 + 6H20 + light C6H12O6 + 6O2 The photosynthetic process occurs only in the chloroplasts, tiny subcellular structures contained in the cells of leaves and green stems. (See chloroplasts at http://www.cellsalive.com/cells/chloropl.htm.) This process is directly dependent on the supply of water, light, and carbon dioxide. Limiting any one of the factors on the left side of the equation (carbon dioxide, water, or light) can limit photosynthesis regardless of the availability of the other factors. If this happens, then the whole process slows down or stops. Plants use the glucose as a basic building block to synthesize a number of complex, carbon-based biochemicals used to grow and sustain life. Photosynthesis and respiration are complementary processes in the living world. Photosynthesis uses the energy of sunlight to produce glucose (sugars) and other organic molecules. These molecules 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 for energizing life processes (metabolic processes). The chemical equation for respiration shows that the glucose from photosynthesis is combined with oxygen. Notice that the equation for respiration is the opposite of that for photosynthesis: C6H12O6 + 6O2 6CO2 + 6H20 + energy Most respiration processes take place in another subcellular organelle, the mitochondrion. (See mitochondria at http://www.cellsalive.com/cells/mitochon.htm.) 
In summary, respiration is the breaking down of glucose for energy to grow and do the internal work of cells. It is very important to understand that both plants and animals (including microorganisms) carry out respiration. Table 1. Comparison of Photosynthesis and Aerobic (Oxidative) Respiration
Introduction1. Have students answer the following simple questions to find out what they already know: 1. Why do you breathe? 2. What do you breathe? 3. Do plants breathe? 4. What do plants breathe? 5. What would happen to an aquarium plant (Elodea) if we moved the aquarium from its sunny window location to a dark closet? 6. What would happen to an aquarium snail if we put it into a container of aquarium water and sealed the container? 7. What would happen to an aquarium plant (Elodea) if we put it into a container of aquarium water and sealed the container? 8. What would happen to an aquarium plant (Elodea) and a snail if we put them into a container of aquarium water and sealed the container?
Pre-Lab Activity1. Have students design an experiment, using the materials listed under “Materials needed” and questions 5–8 above, as shown on the student activity sheet. 2. Have the students begin by developing a hypothesis for each question, using a Developing a Hypothesis table, as shown on the student activity sheet. A completed table is shown on the next page. Developing a Hypothesis
Adapted from: Science Experiments by the Hundreds, Julia H. Cothron, Ronald N. Giese, Richard J. Rezba, Kendall/Hunt Publishing Company, 2004. Used by permission. 3  Low------------pH---------High CO2-----------------------no CO2 . Explain that in order to test their hypotheses and get quick, accurate results, a solution called an “indicator” can be used. Bromthymol blue (BTB) is an indicator used to show the presence of either carbon dioxide in solution or an acidic solution. Low levels of carbon dioxide or acid will result in the bromthymol blue solution remaining blue, while higher levels of carbon dioxide or acid will result in the bromthymol blue solution taking on a yellow tint. Frequently this indicator is used to indicate photosynthetic activity (solution turns blue because CO2 is used up) or respiratory activity (solution turns yellow because CO2 is added to the solution). 4. Stimulate discussion by asking: “How might your hypotheses change if you plan on using the indicator?” Still qualitative, but able to see that pH changes are occurring. Students could test the time needed to change and/or the exact color change. ProcedureSafety Note: Students must wear protective eyewear! 1. Have the students number the containers 1 through 4 and fill each about 4/5 full with aquarium water. 2. Have students add enough of the bromthymol blue solution (2 to 3 mL) to each bottle to obtain a green color. 3. Direct students to add the following items to the containers and then to seal them tightly: #1. Sprig of Elodea #2. Snail #3. Sprig of Elodea and Snail #4. Nothing (the control) 4. Place the containers near a light source. 5. Have students predict the color the water in the containers will turn in a few hours. Have them explain their predictions. 6. Have students fill in the Experimental Design table on the student activity sheet. A sample filled-in table is shown below: Experimental Design Table
Observations and Conclusions1. Within a few hours, the following results should be noticed: Containers 3 and 4 should remain green, though container 3 may turn a slightly different shade of green. Container 1 should be blue, and container 2 should be yellow. Have students explain their observations. 2. Ask the student the following investigator questions: Why did the control (water only) stay the same color? Explain what happened in container 3 (water + Elodea + snail), using the photosynthesis and respiration chemical equation. What is at equilibrium? Which container is closest to achieving equilibrium? What would happen if all containers were kept in a dark place? (See Extension 1 below.) Could this experiment go on indefinitely? Why, or why not? Observations and Conclusions1. Hold a class discussion that included the following: Carbon dioxide dissolves in (and reacts with) water, forming carbonic acid, H2CO3. Carbonic acid then immediately dissociates into a hydrogen ion and a bicarbonate ion. The reaction occurring in solution is CO2(g) + H2O(l) H2CO3 H+(aq) + HCO3–(aq) The free hydrogen ions (H+) lower the pH of the solution, making it more acidic. The degree to which the pH changes is proportional to the amount of CO2 that dissolves in the water. In other words, as more CO2 dissolves in water, the pH of the solution will continue to decrease. If CO2 is removed from the solution, the pH will increase. A pH indicator, such as bromthymol blue, can therefore indicate the relative amount of CO2 dissolved in water based on the color of the solution. In this activity, photosynthesis occurring in the Elodea exposed to light removes CO2 from the solution and thereby raises the pH. This higher pH is indicated by the blue color of the indicator in container 1. The Elodea also is respiring or carrying out life processes. The snail, on the other hand, only respires, producing CO2 and thereby lowering the pH. This lower pH is indicated by the yellow color of the indicator in container 2. Container 3 will have a relatively neutral pH, since the snail is respiring and the plant is both respiring and also photosynthesizing. The color of the indicator in container 4 should not change. Directory: testing -> sol -> scope sequence scope sequence -> History and Social Science Standards of Learning Enhanced Scope and Sequence sol -> Strand Earth Patterns, Cycles, and Change Topic Investigating fossils in sedimentary rock Primary sol testing -> Prairie State Achievement Exam testing -> Testing and Assessment updated Tentative schedules testing -> Local unit tests Located at module-name sol -> P. O. Box 2120 Richmond, Virginia 23218-2120 sol -> Strand Interrelationships in Earth/Space Systems Topic Investigating ocean currents Primary sol sol -> History and Social Science Standards of Learning for Virginia Public Schools Wo Board of Education Commonwealth of Virginia March 2015 History and Social Science Standards of Learning for Virginia Public Schools Adopted in March 2015 by the Board of Download 3.95 Mb. Share with your friends:
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