Photosynthesis
Redox Reactions break bonds & move electrons from one molecule to another as electrons move they carry energy with them that energy is stored in another bond, released as heat or harvested to make ATP loses e- gains e- oxidized reduced + + + e - e - oxidation redox e - reduction
How do we move electrons in biology? Moving electrons in living systems electrons cannot move alone in cells electrons move as part of H atom move H = move electrons loses e- gains e- oxidized reduced + + + H oxidation e p H reduction
Redox in biology The atoms that H tends to bond with in biology attract electrons more (more electronegative) Essentially moving H is moving electrons Oxidation is losing hydrogen atoms Reduction is gaining hydrogen atoms
Energy for life The energy captured through photosynthesis forms the basis of the ecological pyramid.
Energy needs of Life Autotrophs (Plants) producers produce their own energy (from self ) convert energy of sunlight build organic molecules (CHO) from CO 2 make energy & synthesize sugars through photosynthesis
Energy needs of life All life needs a constant input of energy consumers Heterotrophs (Animals) get their energy from eating others eat food = other organisms = organic molecules make energy through respiration
2007-2008
How are they connected? Cellular Respiration making energy & organic molecules from ingesting organic molecules glucose + oxygen carbon + water + energy dioxide C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + ATP exergonic Photosynthesis making energy & organic molecules from light energy carbon dioxide + water + energy glucose + oxygen 6CO 2 + 6H 2 O + light C 6 H 12 O 6 6O energy + 2 endergonic
What does it mean to be a plant Need to collect light energy transform it into chemical energy ATP glucose need to get building block atoms from the environment C,H,O,N,P,K,S,Mg produce all organic molecules needed for growth CO 2 N K P H 2 O
Plant structure Obtaining raw materials sunlight leaves = solar collectors CO 2 stomata = gas exchange H 2 O uptake from roots nutrients N, P, K, S, Mg, Fe uptake from roots
stomata transpiration gas exchange
leaves Chloroplasts cross section of leaf absorb sunlight & CO 2 CO 2 chloroplasts in plant cell chloroplast chloroplasts contain chlorophyll make energy & sugar
Plant structure Chloroplasts double membrane stroma fluid-filled interior thylakoid sacs grana stacks Thylakoid membrane contains chlorophyll molecules electron transport chain ATP synthase H + gradient built up within thylakoid sac chloroplast stroma ATP H +H+ H + H + H +H+ H+ H + outer membrane thylakoid granum H +H+ H + thylakoid inner membrane
Photosynthesis Light reactions light-dependent reactions energy conversion reactions convert solar energy to chemical energy ATP & NADPH Calvin cycle light-independent reactions sugar building reactions uses chemical energy (ATP & NADPH) to reduce CO 2 & synthesize C 6 H 12 O 6
Things that happen in the Light Reaction Light absorbed by chlorophyll This drives the transfer of H to an electron acceptor called NADP+ which temporarily stores energized electron. ADP ATP (phosphorylation) O2 is given off as a byproduct because water is split Two forms of compounds hold chemical energy: NADPH and ATP
Calvin Cycle CO2 gets incorporated into organic compounds in plant (C6H12O6) Carbon-fixation NADPH gives H atoms to CO2 (requires ATP)
I see the Light! Light is a flow of energy called electromagnetic energy/radiation and travels in waves Photons are fixed energy in light
Pigments of photosynthesis Chlorophylls & other pigments embedded in thylakoid membrane arranged in a photosystem collection of molecules
A Look at Light The spectrum of color V I B G Y O R
Excitation of Chlorophyll by Light When hit with a photon, an electron is elevated to the next orbital. It is excited and unstable. If the electron has no where to go, it emits light and heat when it falls back to its original state.
Diagram Using your notes and the book, draw a detailed diagram of the light reaction and Calvin cycle in the chloroplast. Include what is used at each stage, what is produced and what moves on.