logging in or signing up photosynthesis Ulisse Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINTLite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Dynamic Copy Does not support media & animations Automatically changes to Flash or non-Flash embed WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 1003 Category: Entertainment License: All Rights Reserved Like it (0) Dislike it (0) Added: January 12, 2008 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript Photosynthesis: PhotosynthesisLeaf Functions: Leaf FunctionsTranspiration: Transpiration Most water loss occurs through stoma, as gas exchange (necessary for phtosynthesis) occurs through stoma water is lost through evaporation Factors effecting transpiration rate - high temperatures, bright light, low humidity all increase rate Cools plant by shedding heat (remember specific heat of water?)Guttation: Guttation Loss of liquid water occurs when water is available but transpiration is low stoma close but plant continues to absorb water (wet plants in morning)Abscission: Abscission Allows deciduous trees to survive drought and winter low temperature and low moisture cause plant metabolism to slow down. No need for leaves… Plant reabsorbs sugars, starches from leaves Abscission zone (pg 535) Tension-cohesion mechanism: Tension-cohesion mechanism Water is pulled up the stem of a tree by the suction caused by the evaporative loss of water through the leaves Column of water is unbroken because of the cohesive and adhesive tendencies of water molecules page 550-551Photosynthesis: Photosynthesis 1st Law of Thermodynamics ? 2nd Law of Thermodynamics? Entropy - the measure of disorder in a system Free energy - the amount of energy avilable to do work Chemical Reactions: Chemical Reactions Exergonic - release energy Endergonic - absorb energy, require energy for reaction to occur some chemical reactions can be reversed! Dynamic equilibrium Adenosine triphosphate (ATP): Adenosine triphosphate (ATP) Modified nucleotide (related to DNA and RNA) with 3 inorganic phosphate groups attached at one end of molecule Phosphate groups are readily attached (endergonic) or detached (exergonic) by adding water. Activation energy: Activation energy Is the energy required to initiate a reaction Enzymes are biological catalysts, that is, the act to increase the rate of a chemical reaction but are not consumed by it Enzymes are specific in that certain enzymes work on certain reactions in a certain orderPhotosynthesis Links: Photosynthesis Links Enzymes act to increase the rate of a reaction by lowering the activation energy required. Visit http://khanda.unl.edu/~nikku/atp.html for more info...Photosynthesis: Photosynthesis Chlorophyll is a green pigment that absorbs light in the first step in photosynthesis Pigments are located in sacks called thylakoids within the chloroplasts of plant cells. The thylakoids are stacked in groups called grana Light dependent reactions: Light dependent reactions Chlorophyll absorbs light, energized electrons flow from the chlorophyll molecule energy is used by phosphorylate adenosine diphosphate (ADP) to add a phospahte group to form ATP some energy is used to split water moleculeLight Dependent Reactions: Light Dependent Reactions Oxygen is released hydrogen combines with a molecule called NADP+ that carries an extra electron to form NADPH NADPH stores the sunlight as chemical energy NADPH provides the energy to add the phosphate group to ADP to form ATPThe Dark Reaction: The Dark Reaction Carbon dioxide is not used in the light dependent reactions and glucose is not formed these are not light dependent activities Dark reactions = Calvin Cycle products of the light reactions are used to form glucosePhotosynthesis and food: Photosynthesis and food All food comes from photosynthesis Plants allows us to harvest solar energy and convert it into energy we can use Light energy is converted into chemical energy which is converted into sugars and starches oxygen is releasedEnergy : Energy Photosynthesis stores solar energy in the forms of plants…wood….coal and oil…ethanol…natural gasMaterials: Materials Solar energy converted into fibers…cotton, wool… wood …paper…synthetic fibers from petroleum…. You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.