Energy Flow in Organisms

1. Georgia Performance Standards-- Relate the complexity and organization of organisms to their ability for obtaining & transforming the matter and energy used to sustain the organisms. Essential Questions: - How does and energy flow through a plant?

2. Hook Suppose you earned extra money by having a part-time job. At first, you might be tempted to spend all of the money, but then you decide to open a bank account. 1. What are the benefits of having a bank account? 2. What do you have to do if you need some of this money? 3. What might your body do when it has more energy than it needs to carry out its activities? 4. What does your body do when it needs energy?

3. All living things need energy. Some are more obvious than others. Are we still using energy while we sleep? • Where does energy come from?

4. Photosynthesis

5. ENERGY and LIFE Every living things requires energy (from food) to survive. Autotrophs: make their own food (plants) Heterotrophs: consume their food (animals, fungi, yeasts) Chemical energy = energy stored in molecules

6. How do cells store energy? 1. ATP - Adenosine triphosphate *Easy for cells to use *Basic energy source for cells; used to power cell processes. Ex: active transport *Good at transferring E; Cannotstore large amounts of energy for long amounts of time

7. Comparison of ADP and ATP to a Battery ADP ATP Energy Energy Adenosinediphosphate (ADP) + Phosphate Adenosine triphosphate (ATP) Partially charged battery Fully charged battery

8. How do cells store energy? 2. Glucose *Lots of energy (90 times more than 1 ATP molecule) *Not as accessible for cell processes, better for storage *Can be used to make more ATP (ADP-> ATP)

9. Checkpoint Questions: • What is the ultimate source of energy for plants? • What is ATP and what is its role in the cell? 3. Describe cellular activities that use the energy released by ATP. 4. How do autotrophs obtain energy? How do heterotrophs obtain energy? 5. With respect to energy, how are ATP and glucose similar? How are they different?

10. Warm-up: Trapping Energy • Have you ever used a solar-powered calculator? • No matter where you go, as long as you have a light source, the calculator works. You never have to put batteries in it.

11. 1. A solar-powered calculator uses solar cells that are found in rows along the top of the calculator. Into what kind of energy is the light energy converted so that the calculator works? 2. Recall that plants use light energy from the sun to make food. Into what kind of energy is the light energy converted by plants? 3. Most plants, no matter what size or shape they are, have some parts that are green. Which parts of a plant are usually green? 4. What does the green color have to do with the plant’s ability to convert light energy into the energy found in the food it makes? Warm-up: Trapping Energy

12. How do cells get ATP and glucose? PHOTOSYNTHESIS Photosynthesis – Plants use energy from sunlight to convert H2O and CO2 into O2 and sugars.

13. Seedling  Tree

14. Experiments that help us understand photosynthesis Jan van Helmont (1643) Question: Do plants gain mass (grow) by taking material out of the soil? Experiment: Over 5 years, he measured the mass of the soil and the plant. Conclusion: Mass of plant comes from water, not soil.

15. Experiments that help us understand photosynthesis Joseph Priestley (1771) Question: Why does a candle remain burning under a jar when a plant is under the jar? Answer: A plant produces a substance (oxygen) required for burning.

16. Experiments that help us understand photosynthesis Jan Ingenhouz (1779) Repeated Priestley’s experiment in light and dark. Question: Does light affect the candle burning when a plant is present? Answer: Light is required for plants to produce oxygen.

17. Experiments that help us understand photosynthesis From these experiments we know: With light, plants transform water and carbon dioxide into carbohydrates and oxygen

18. How do plants use light? Light is a form of energy Pigments - molecules that absorb specific wavelengths of light Chlorophyll - main pigment found in plants Two types: Chlorophyll A and Chlorophyll B; What colors do they absorb easily?

19. Light & Chlorophyll Pigments: • Photosynthesis Also Requires Light and Chlorophyll Pigments • Sunlight is seen as white light (a mixture of different wavelengths of light) • Wavelengths of visible light are seen as certain colors • Review Spectrum of visible Light • Plants appear green because that is the color that is reflected. • The other colors of light are being absorbed.

20. Chlorophyll Light Absorption Absorption of Light by Chlorophyll a and Chlorophyll b Chlorophyll b Chlorophyll a V B G Y O R Photosynthesis requires light and chlorophyll, which absorbs light energy. In the graph, notice how chlorophyll a absorbs light in the violet and red regions of the visible spectrum, while chlorophyll b absorbs light in the blue and red regions of the visible spectrum.

21. Checkpoint: • Describe the process of photosynthesis, including the reactants and products. • Why are light and chlorophyll needed for photosynthesis? • Why are plants green? • How well would a plant grow under pure yellow light? Explain your answer.

22. How do plants use light? *When chlorophyll absorbs light, it absorbs energy *That energy is transferred to electrons *Those electrons power photosynthesis Electron carriers - molecules that transfer high energy electrons from chlorophyll to other molecules Example: NADP+ (nicotinamide adenine dinucleotide phosphate) can accept 2 high energy electrons. 2 electrons + NADP+ -> NADPH

23. Photosynthesis takes place in the chloroplast of the cell. Stroma - space outside the thylakoids granum - stack of thylakoids grana - plural of granum thylakoid - membrane sacs that contain pigments to absorb light energy

24. Two parts to photosynthesis: 1. Light Dependent Reactions - process that uses light to produce oxygen, ATP, and NADPH. Occurs in the thylakoid membrane 2. Light Independent Reactions (Calvin Cycle) - process that uses ATP and NADPH to produce high energy sugars. Occurs in the stroma.

26. Light Dependent Reactions • Require Light !! • Occurs in the thylakoid membranes • Produce oxygen and convert ADP and NADP+  ATP and NADPH • Basic Goal- Light  Chemical Energy

27. Light Dependent Reactions Photosystem II: E from light is absorbed by chlorophyll and transferred to electrons; then, these high E electrons are passed to the Electron Transport Chain Photosystem I : Pigments use light to re-energize the electrons

28. Calvin Cycle AKA Light-Independent Reactions • Basic Goal: Takes the Chemical Energy and Converts it to High energy sugars (ex. Glucose) • Occurs in Stroma!!! • Uses ATP and NADPH to produce high energy sugars

29. Light- dependent reactions Calvincycle Energyfrom sunlight Thylakoid membranes ATP Stroma NADPH High-energy sugars ATP NADPH O2 Chloroplasts Concept Map Section 8-3 Photosynthesis includes takes place in uses use take place in to produce to produce of Go to Section:

30. What Affects Photosynthesis??? • Shortage of water • Temperature (Best at 0-35 degrees Celsius) • Intensity of light.

31. Checkpoint: • Summarize the light-dependent reactions. • What reactions make up the Calvin cycle? 3. What is the function of NADPH? 4. How is light energy converted into chemical energy during photosynthesis? 5. Can the complete process of photosynthesis take place in the dark? Explain your answer.