Chapter 6.3-6.4 & 7: Energy and Life PDF

Chapter 6.3-6.4 & 7 Energy and Life  Learning Objectives  Today you will learn to:  Explain how light is the initial source of energy for most communities.  Compare autotrophs and heterotrophs; define, give examples of each, explain their role in an ecosystem....

Chapter 6.3-6.4 & 7 Energy and Life  Learning Objectives  Today you will learn to:  Explain how light is the initial source of energy for most communities.  Compare autotrophs and heterotrophs; define, give examples of each, explain their role in an ecosystem.  Describe the role of ATP in the storage and release of chemical energy in the cell.  Recognize the equation for photosynthesis and identify the reactants and products. Describe the function, organelle where it occurs, and organisms that perform it. Unit Organizer Cell Energy is about Energy Use within Cells in its as it is Forms stored in Producers through Photosynthesis using LD Calvin Reaction Cycle  Energy and Life  Energy-  The ability to do work  Without it life would not exist  Ultimate source  The sun Autotrophs and Heterotrophs  Plants and some other organisms produce food from sunlight  Autotrophs  Organisms that must consume others for food  Heterotrophs  Word Origins  Autotroph comes from the Greek words:  autos = self  trophe = food Autotrophs make food for themselves mostly through photosynthesis!  Heterotroph comes from the Greek words:  heteros = other  trophe = food Heterotrophs get food from others! ***Mushrooms do not use the sun, they are heterotrophs!!  Chemical Energy  Recall chemical reactions break or form bonds to release energy  ATP or Adenosine TriPhosphate is the compound cells use to store and release energy for cells  Chemical Energy and ATP ATP consists of:  adenine  ribose (a 5-carbon sugar)  3 phosphate groups Adenine Ribose 3 Phosphate groups  Chemical Energy and ATP Releasing the Stored Energy Energy stored in ATP is released by breaking the chemical bond between the second and third phosphates. 2 Phosphate groups P ADP  ADP vs ATP  ADP  ATP  Has 2 phosphate  Has 3 phosphate groups groups  Like a partially  Like a fully charged battery charged battery  Exceptionally useful as the basic source of energy of all cells  Using Biochemical Energy  Cells use the energy provided by ATP to carry out work like active transport, move and grow.  ATP  Great molecule for transferring energy  Not good for storing large amounts of energy over the long term.  ATP vs Glucose  ATP is like coin $ = it is  Glucose is like paper $ useful, but bulky and = it is worth more and heavy. Good for short less bulky. Plants use term uses. glucose for longer term storage of energy. History of Photosynthesis  1643 - Jan van Helmont determined that plants mass comes from water  1771 - Joseph Priestly found plants release oxygen  1779 - Jan Ingenhouz found plants need sunlight to produce oxygen (produce bubbles in light, but not in dark)  What is Photosynthesis?  How plants (along with some protists & bacteria) use solar energy to combine water and carbon dioxide into high- energy carbohydrates (sugars and starches) and release oxygen into the environment.  Photosynthesis Equation sunlight 6CO2 + 6H2O  C6H12O6 + 6O2 Reactants Products sunlight Carbon dioxide + water  sugar + oxygen Reactants Products  Where Does Photosynthesis Take Place?  IN CHLOROPLASTS  Contains chlorophyll pigment that trap sunlight  The light energy gets converted into chemical energy (carbohydrates)  Photosynthesis occurs in chloroplasts in plant cells  Chloroplasts are concentrated in the cells of the mesophyll, the green tissue in the interior of the leaf.  Stomata are tiny pores in the leaf that allow  carbon dioxide to enter and  oxygen to exit.  Veins in the leaf deliver water absorbed by roots. Figure 7.2-1 Leaf Cross Section Mesophyll Leaf Vein Mesophyll Cell CO2 O2 Stoma Chloroplast Figure 7.2-2 Mesophyll Cell Chloroplast Inner and outer membranes Granum Thylakoid Thylakoid space Stroma  Photosynthesis is a redox process, as is cellular respiration  In photosynthesis,  light energy is captured by chlorophyll molecules to boost the energy of electrons,  light energy is converted to chemical energy, and  chemical energy is stored in the chemical bonds of sugars. Figure 7.6a Shorter wavelength Longer wavelength Higher energy Lower energy 10−5 nm 10−3 nm 1 nm 103 nm 106 nm 1m 103 m Gamma Micro- Radio X-rays UV Infrared rays waves waves Visible light 380 400 500 600 700 750 Wavelength (nm)  Visible radiation absorbed by pigments drives the light reactions  Plant pigments  are built into the thylakoid membrane,  absorb some wavelengths of light, and  reflect or transmit other wavelengths.  We see the color of the wavelengths that are transmitted. For example, chlorophyll transmits green wavelengths. What are the reactions of photosynthesis?  Light dependent reactions take place in thylakoid  Produces ATP and NADPH (short-term use energy)  Requires light  Light independent reactions (aka Calvin cycle) takes place in surrounding area (stroma)  Produces glucose (long-term use energy)  Does not require light Figure 7.8 The light ATP dependent reaction works kind of like this… NADPH Electron n Photo transport chain ramp Photon Photosystem II Photosystem I Figure 7.9-0 Thylakoid sac In reality it’s more Chloroplast like this… Light Photosystem H+ Electron Light transport chain Photosystem NADP+ + H+ II I NADPH H+ H+ H+ H+ H+ H+ H2O H+ H+ To 1 O2 + 2 H+ H+ H+ 2 H+ Calvin Cycle H+ H + THYLAKOID SPACE H+ H+ H+ H+ H+ H+ H + Thylakoid membrane ATP synthase H+ STROMA H+ H+ H+ ADP + P ATP H+ Photosynthesis with Bill Nye Figure 7.5-1 H 2O Light NADP + ADP + P Light Reactions (in thylakoids) Chloroplast Figure 7.5-2 H 2O Light NADP + ADP + P Light Reactions (in thylakoids) ATP NADPH Chloroplast O2 Figure 7.5-3 H 2O CO2 Light NADP + ADP + P Calvin Light Cycle Reactions (in stroma) (in thylakoids) ATP NADPH Notice the reactants of Chloroplast photosynthesis entering the top and the O2 Sugar products leaving the bottom. What happens?  NADPH and ATP are not very stable, so they must be used quickly or…  They go on to the next step, the light independent reaction where high energy compounds (sugars) are produced that can be stored for later use Figure 7.10-0 H2O CO2 Light NADP+ ADP + P Light Calvin Input Reactions Cycle ATP 3 CO2 Step 1 NADPH Carbon fixation Chloroplast Rubisco O2 Sugar 6 P 3 P P 3-PGA RuBP 6 ATP 3 ADP Step 4 P 6 ADP + P P Regeneration of RuBP CALVIN 3 ATP CYCLE 6 NADPH 6 NADP+ 6 P 5 P G3P G3P Step 2 Step 3 Reduction Release of one molecule of G3P 1 P G3P Glucose and other Output compounds  Photosynthesis provides food for almost all living organisms  Most plants make much more food each day than they need. They store the excess in  roots,  tubers,  seeds, and  fruits.  Plants (and other photosynthesizers) are the ultimate source of food for virtually all other organisms.  Photosynthesis Equation sunlight 6CO2 + 6H2O  C6H12O6 + 6O2 sunlight Carbon dioxide + water  sugar and oxygen What effect would photosynthetic bacteria have had on Earth’s early atmosphere? How would they have changed it?  Photosynthesis Equation sunlight 6CO2 + 6H2O  C6H12O6 + 6O2 sunlight Carbon dioxide + water  sugar and oxygen They would have emitted O2 What Affects Photosynthesis?  Water  Can slow or stop reaction  Plants adaptations help prevent water loss  Temperature  Plants go dormant in the winter  Intensity of Light  Increased light = increased photosynthesis to a point  Section Review 1. Explain how light is the initial source of energy for most communities. 2. Compare autotrophs and heterotrophs; define, give examples of each, explain their role in an ecosystem. 3. Describe the role of ATP in the storage and release of chemical energy in the cell. 4. Recognize the equation for photosynthesis and identify the reactants and products. Describe the function, organelle where it occurs, and organisms that perform it.