Synthesis and decomposition material

Synthesis Photosynthetic plants Photosynthetic bacteria Chemoautotrophic bacteria Light Energy Harvested by Plants CO2 + H2O + light energy → C6H12O6 + O2 Where the Photosynthesis Occurs? Photosynthesis takes place within leaf (or green stem) cells containing chloroplasts • each cell contains 40 to 50 chloroplasts • a chloroplast has dozens of the thylakoids and millions of pigment molecules • each thylakoid contains thousands of photosystems The thylakoid membrane of the chloroplast is impregnated with photosynthetic pigments Thylakoid Overview of photosynthesis There are three basic steps in photosynthesis: (1) Light Reactions - energy capture (2) Dark Reactions - fixation of carbon (3) Pigment Regeneration electron replacement from the splitting of H2O in oxygenic photosynthesis Overview of photosynthesis • The light reactions convert solar energy to chemical energy Chloroplast Light – Produce ATP & NADPH • The Calvin cycle makes sugar from carbon dioxide – ATP generated by the light reactions provides the energy for sugar synthesis – The NADPH produced by the light reactions provides the electrons for the reduction of carbon dioxide to glucose NADP+ ADP +P Light reactions Calvin cycle Chloroplast Pigments • Chloroplasts contain several pigments – Chlorophyll a – Chlorophyll b – Carotenoids Chlorophyll a & b •Chl a has a methyl group •Chl b has a carbonyl group Porphyrin ring delocalized e- Phytol tail Different pigments absorb light differently Questions What is the comparison between c3 plant and c4 plant also,c4 plant and CAM? Production of ATP during glycolysis glucose ADP + Pi ATP pyruvic acid Production of ATP during breakdown of pyruvic acid pyruvic acid 36 ADP + 36 Pi In the presence of oxygen carbon dioxide 36 ATP + water Total production of ATP during aerobic respiration Stages of aerobic respiration Number of ATP molecules Stage 1: glycolysis Stage 2: breakdown of pyruvic acid 36 Total overall process of aerobic respiration 38 Anaerobic Respiration Organisms www.the-scientist.com Anaerobic Respiration in Animals In the absence of oxygen, glucose cannot be broken down into carbon dioxide and water Therefore, glucose is only partly broken down and only a few molecules of ATP are released Anaerobic respiration is the breakdown of glucose in cells in the absence of oxygen Anaerobic Respiration in Animals glucose Glycolysis takes place, as in aerobic respiration pyruvic acid lactic acid In the absence of oxygen, pyruvic acid is converted to lactic acid Production of ATP during anaerobic respiration glucose ADP + Pi ATP pyruvic acid No ATP molecules are formed lactic acid Production of ATP during anaerobic respiration Stages of anaerobic respiration Number of ATP molecules Stage 1: glycolysis Stage 2: breakdown of pyruvic acid Total overall process of anaerobic respiration Anaerobic Respiration in Plants and Yeast glucose ADP + Pi ATP pyruvic acid No ATP molecules are formed ethanol + carbon dioxide Comparing Aerobic and Anaerobic Respiration Glycolysis ATP yield Aerobic Anaerobic Anaerobic respiration Animals Plants/Yeast Yes Yes Yes 38 2 (per glucose molecule) Product (s) Carbon Lactic acid Ethanol and dioxide carbon and water dioxide Fermentation Fermentation pathways a Homolactic acid fermentation Pyruvic axit -> Lactic Acid eg Streptococci, Lactobacilli b Alcoholic fermentation Pyruvic axit -> Ethyl alcohol eg yeast Fermentation pathways Fermentation Organisms Saccharomyces Cryptococcus neoformans Roles of the decomposition process Decomposition is a complex process involving a variety of organisms Decomposers are organisms that feed on dead organic matter or detritus Involves the release of energy and ultimately the conversion of organic compounds into inorgarnic nutrients Complex of many process: leaching, fragmentaion, changes in physical and chemical structure, ingestion and excretion of waste products ... comparison between c3 plant and c4 plant also,c4 plant and CAM? C3 plants • oldest form of carbon fixation • 95% of current plants use c3 fixation • carbon fixation and photosynthesis occurs exclusively... requires more energy CAM • both fixation and photosynthesis take place in mesophyll cells • carbon fixation is temporally separated from photosynthesis and only takes place at night • stomata... Cyanobacteria Overview of photosynthesis S H2S Reaction: CO2 + 2H2A -> CH20 + H20 +2A Photosynthesis A is not O Light Energy CO2 Glucose + H2O Bacteria Photosynthesis • Only one photosystem