Photosynthesis Interest Grabber Photosynthesis converts light energy into chemical energy Plants and some other types of organisms (all of which are autotrophes) are able to use light energy from the sun to produce food 1 Saving for a Rainy Day 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? 2 8 1 Energy and Life A. Autotrophs and Heterotrophs 3 Autotrophes These form the base of all ecosystems Use energy from the sun to produce C 6 H 12 O 6 (sugar/food) from CO 2 + H 2 O (carbon dioxide + water) These are called photoautotrophes (>99% of all producers) Some use the energy stored in the chemical bonds of inorganic molecules These are called chemoautotrophes (< 1% of all producers) 4 1
Heterotrophes Upper levels of trophic level pyramids are made up of these animals, protists, some bacteria and some fungi. These are the consumers they get their energy from food they consume (either plants or animals) On which trophic level do these herbivores belong? 5 8 1 Energy and Life A. Autotrophs and Heterotrophs B. Chemical Energy and ATP 1. Storing Energy 2. Releasing Energy 6 Parts of the ATP molecule: Storing energy by adding energy and phosphate to ADP Adenine Ribose 3 Phosphate groups ADP ATP Energy Adenosine diphosphate (ADP) + Phosphate Energy Adenosine triphosphate (ATP) Partially charged battery Fully charged battery 7 Figure 8-3 Comparison of ADP and ATP to a Battery 8 2
Releasing energy by subtracting a phosphate from ATP Figure 8-3 Comparison of ADP and ATP to a Battery ATP ADP ADP ATP Energy Energy Energy Adenosine diphosphate (ADP) + Phosphate Energy Adenosine triphosphate (ATP) Adenosine triphosphate (ATP) Adenosine diphosphate (ADP) + Phosphate Partially charged battery Fully charged battery 9 Figure 8-3 Comparison of ADP and ATP to a Battery 10 Adding energy allows a phosphate to be added and the energy is stored in the bond 8 1 Energy and Life A. Autotrophs and Heterotrophs B. Chemical Energy and ATP 1. Storing Energy 2. Releasing Energy C. Using Biochemical Energy 12 11 3
Using ATP in the cell Section 8-2 Interest Grabber Active transport Synthesis Proteins Trapping Energy Have you ever used a solar-powered calculator? No matter where you go, as long Nucleic acids as you have a light source, the calculator works. You never have to put batteries in it. Produce light!! 13 14 Section 8-2 Interest Grabber continued 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? Section 8-2 8 2 Photosynthesis: An Overview A. Investigating Photosynthesis 1. Van Helmont s Experiment 2. Priestley s Experiment 3. Jan Ingenhousz 15 16 4
Van Helmont s Experiment Priestley s Experiment In the 1600s, the Belgian physician Jan van Helmont devised an experiment to find out if plants grew by taking material out of the soil. determined the mass of a pot of dry soil and a small seedling He watered it regularly. At the end of five years, the seedling, which by then had grown into a small tree, had gained about 75 kg The mass of the soil, however, was almost unchanged. Conclusion? That most of the gain in mass had come from water, because that was the only thing that he had added. (the carbon for carbohydrates comes from the CO 2 in the atmosphere) 17 1771- Priestley took a candle, placed a glass jar over it, and watched as the flame gradually died out. Something in the air, Priestley reasoned, was necessary to keep a candle flame burning. When that substance was used up, the candle went out. That substance was oxygen. Priestley then found that if he placed a live sprig of mint under the jar and allowed a few days to pass, the candle could be re-lighted and would remain lighted for a while. The mint plant had produced the substance required for burning. In other words, the mint released oxygen. 18 Jan Ingenhousz s Experiment 1779 - Dutch scientist Ingenhousz showed that the effect observed by Priestley occurred only when the plant was exposed to light. The results of both Priestley's and Ingenhousz's experiments showed that light is necessary for plants to produce oxygen. 19 Section 8-2 8 2 Photosynthesis: An Overview A. Investigating Photosynthesis 1. Van Helmont s Experiment 2. Priestley s Experiment 3. Jan Ingenhousz B. The Photosynthesis Equation C. Light and Pigments 20 5
Photosynthesis: Reactants and Products Section 8-2 Light Energy What is the basic equation for photosynthesis? 6H 2 O + 6CO 2 C 6 H 12 O 6 + 6O 2 Water plus carbon dioxide plus light yield sugar and oxygen 21 Chloroplast CO 2 + H 2 O Sugars + O 2 22 Section 8-2 Figure 8-5 Chlorophyll Light Absorption Absorption of Light by Chlorophyll a and Chlorophyll b Chlorophyll b Chlorophyll a V B G YO R 23 B This is the visible spectrum of light (what we can see) A 24 (One billionth (10-9 ) of a meter) 6
A Look Into the Future It is 100 years in the future and you are a research scientist. An enormous volcanic eruption has recently sent huge quantities of dust and ash into the atmosphere. In your notes, make a list of how this event will affect each of the following: 1. photosynthesis 2. plant life 3. animal life Interest Grabber 4. human societies 26 8 3 The Reactions of Photosynthesis A. Inside a Chloroplast 27 Structure of Chloroplast Inner membrane outer membrane Stroma Thylakoid Grana 28 29 7
30 31 Figure 8-7 Photosynthesis: An Overview Light-Dependent Reactions, Part 1 Chloroplast Light NADP + ADP + P CO 2 Chloroplast Light- Dependent Reactions O 2 ATP NADPH Calvin Cycle Sugars 32 Click the image to play the video segment. 8
Light-Dependent Reactions, Part 2 8 3 The Reactions of Photosynthesis A. Inside a Chloroplast B. Electron Carriers NADP + +2e - + H + NADPH Click the image to play the video segment. NADPH 35 Concept Map of the rxns of photosynthesis NADPH carries high energy electrons (ATP is a more stable molecule used for cellular processes) 36 use Energy from sunlight H2 O to produce Lightdependent reactions take place in Thylakoid membranes Photosynthesis of includes Stroma ATP NADPH O 2 Chloroplasts takes place in ATP Calvin cycle uses CO 2 to produce High-energy sugars NADPH 37 9
Figure 8-10 Light-Dependent Reactions 8 3 The Reactions of Photosynthesis A. Inside a Chloroplast B. Electron Carriers C. Light-Dependent Reactions Inner Thylakoid Space Photosystem II Hydrogen Ion Movement ATP synthase Chloroplast Thylakoid Membrane 38 Stroma Electron Transport Chain Photosystem I ATP Formation 39 8 3 The Reactions of Photosynthesis A. Inside a Chloroplast B. Electron Carriers C. Light-Dependent Reactions D. The Calvin Cycle 40 CO 2 Enters the Cycle 5-Carbon Molecules Regenerated Sugars and other compounds Energy Input 6-Carbon Sugar Produced Calvin Cycle ChloropIast 41 10
ATP Formation Calvin Cycle Click the image to play the video segment. Click the image to play the video segment. 8 3 The Reactions of Photosynthesis A. Inside a Chloroplast B. Electron Carriers C. Light-Dependent Reactions D. The Calvin Cycle E. Factors Affecting Photosynthesis 44 Factors Affecting Photosynthesis: light intensity 45 11
Factors Affecting Photosynthesis: Temperature Factors Affecting Photosynthesis: CO 2 concentration & water 46 47 Follow up: Fill in Concept Map (due at end of period) Back to Warm ups 12