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http://swagct.com/uploads/2012/09/1_1347535212.jpg. Test Corrections: Due 3/28. IF you received a “D” or an “F” Answer each question in a bulleted or numbered format (as seen below)
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Test Corrections: Due 3/28 • IF you received a “D” or an “F” • Answer each question in a bulleted or numbered format (as seen below) • You can earn ½ of the amount of points you lost on the question, only if you answer all the questions for each question you want points back for: • Why did you chose the answer you did? • Why is that answer incorrect? • What is the right answer? • Why is that answer correct?
Extra Credit Essay • Due Today at 3:30
What Would Plants Look Like On Alien Planets? • Switch papers with your table partner
Visible Light • Light is a form of electromagnetic energy, which travels in waves • When white light passes through a prism the individual wavelengths are separated out.
Light Options When It Strikes A Leaf • Reflect – a small amount of light is reflected off of the leaf. Most leaves reflect the color green, which means that it absorbs all of the other colors or wavelengths. • Absorbed – most of the light is absorbed by plants providing the energy needed for the production of Glucose (photosynthesis) • Transmitted – some light passes through the leaf
Mesophyll Chloroplast 5 µm Outer membrane Intermembrane space Thylakoid Thylakoid space Granum Stroma Inner membrane 1 µm Chloroplast • Are located within the palisade layer of the leaf • Stacks of membrane sacs called Thylakoids • Contain pigments on the surface • Pigments absorb certain wavelengths of light • A Stack of Thylakoids is called a Granum
Mesophyll Chloroplast 5 µm Outer membrane Intermembrane space Thylakoid Thylakoid space Granum Stroma Inner membrane 1 µm Chloroplast • Are located within the palisade layer of the leaf • One Membrane sacs called Thylakoids • Contain pigments on the surface • Pigments absorb certain wavelenghts of light • A Stack of Thylakoids is called a Granum
PHOTOSYNTHESIS • Comes from Greek Word “photo” meaning “Light” and “syntithenai” meaning “to put together” • Photosynthesis puts together sugar molecules using water, carbon dioxide, & energy from light.
Happens in two phases • Light-Dependent Reaction • Converts light energy into chemical energy • Light-Independent Reaction • Produces simple sugars (glucose) • General Equation • 6 CO2 + 6 H2O+ light energy C6H12O6 + 6 O2 • INPUTS OUTPUTS
First Phase • Requires Light = Light Dependent Reaction • Sun’s energy excites an electron in the chlorophyll molecule • Electron is passed to nearby protein molecules in the thylakoid membrane of the chloroplast
Excited state e– Heat Energy of election Photon (fluorescence) Ground state Chlorophyll molecule Photon Figure 10.11 A Excitation of Chlorophyll by Light • When a pigment absorbs light it absorbs energy • It goes from a ground state to an excited state, which is unstable
Electron Transport Chain • Electron from Chlorophyll is passed from protein to protein along an electron transport chain • Electrons lose energy (energy changes form) • Finally bonded with electron carrier called NADP+ to form NADPH or ATP • Energy is stored for later use
Two Photosystems • Photosystem II: Clusters of pigments boost e- by absorbing light w/ wavelength of ~680 nm • Photosystem I: Clusters boost e- by absorbing light w/ wavelength of ~760 nm. • Reaction Center: Both PS have it. Energy is passed to a special Chlorophyll a molecule which boosts an e-
e– ATP e– e– NADPH e– e– e– Mill makes ATP Photon e– Photon Photosystem I Photosystem II Figure 10.14 • A mechanical analogy for the light reactions
Thylakoid Photosystem Photon STROMA Light-harvesting complexes Reaction center Primary election acceptor e– Thylakoid membrane Special chlorophyll a molecules Transfer of energy Pigment molecules THYLAKOID SPACE (INTERIOR OF THYLAKOID) Figure 10.12 Photosystem • A photosystem • Is composed of a reaction center surrounded by a number of light-harvesting complexes
H2O CO2 Light NADP ADP + P LIGHT REACTIONS CALVIN CYCLE ATP NADPH Chloroplast [CH2O] (sugar) O2 Figure 10.5
Where did those electrons come from? • Water • Electrons from the splitting of water supply the chlorophyll molecules with the electrons they need • The left over oxygen is given off as gas
High Quality H2O • Electrolysis: Splitting of water with light energy • Hydrogen ions (H+) from water are used to power ATP formation with the electrons • Hydrogen ions (charged particle) actually move from one side of the thylakoid membrane to the other • Chemiosmosis – Coupling the movement of Hydrogen Ions to ATP production
e– ATP e– e– NADPH e– e– e– Mill makes ATP Photon e– Photon Photosystem I (NADPH-producing) Photosystem II (Water-splitting) Figure 10.14 Light-Dependent • Converts light into chemical energy (ATP & NADPH are the chemical products). Oxygen is a by-product
Pigment • Molecules that absorb specific wavelengths of light • Chlorophyll absorbs reds & blues and reflects green
Chlorophyll • Green pigment in plants • Traps sun’s energy • Sunlight energizes electron in chlorophyll
Electron Transport Chain • Series of Proteins embedded in a membrane that transports electrons to an electron carrier
ATP • Adenosine Triphosphate • Stores energy in high energy bonds between phosphates • ATP, or adenosine triphosphate, is a method of energy storage in living organisms
NADPH • During the Light Dependent Cycle of photosynthesis, light is absorbed by the chlorophyll. • The electrons are excited, which starts them moving from one enzyme to another. • A hydrogen atom attaches itself to an NADP+molecule, converting it to NADPH • Stores the high energy electrons for use during light-Independent reaction (Calvin Cycle)
What types of energy are there? Some words you might have used: chemical, potential, gravitational, kinetic, thermal, mechanical…
Engage: What’s Going On Inside a Cell? What types of energy are there? • Food gives us E (energy) but NOT until we break it (down) into anthr (another) form. • Food is stored as chem E (chemical energy). • It has the potential to give us E but not until smthing (something) else is done to it…
Engage: What’s Going On Inside a Cell? Get it Straight… • When we eat a food that has protein (prtn), that protein is notincorp. Immed into our muscles. • The prtn and other nut. are broken into sm. organ. mole. • Remem. from Chap 6 that sm organ. mole.’s r used to build the specific prtn& other mac. mole that r used by plant & animal cells. • So, don’t think that we eat smthg and it goes “straight to our hips” (or muscles or wherever)…
Exit Ticket On a separate sheet of paper answer the following questions: • How do plants get energy and matter for growth? • How is energy transferred from one form to another? • How do plants get their energy from light sources? • What are the inputs and outputs of photosynthesis? • Why does photosynthesis only occur in the chloroplasts?
