Презентація на тему:
Calvin cycle

Photosynthesis: The Calvin Cycle Life from Air AP Biology

The Calvin Cycle AP Biology

Remember what it means to be a plant… Need to produce all organic molecules necessary for growth carbohydrates, lipids, proteins, nucleic acids Need to store chemical energy (ATP) produced from light reactions in stable form can be moved around plant saved for a rainy day AP Biology

Autotrophs Making energy & organic molecules from light energy photosynthesis AP Biology

Light reactions Convert solar energy to chemical energy ATP NADPH What can we do now? energy reducing power build stuff !! AP Biology

How is that helpful? Want to make C6H12O6 synthesis How? From what? What raw materials are available? CO2 C6H12O6 NADPH NADP reduce CO2 carbon fixation AP Biology

Where does CO2 come from Plants get CO2 from air via stomata Have guard cells that open and close stomata Also guard against loss of water vapor AP Biology

From CO2 C6H12O6 CO2 has very little chemical energy fully oxidized C6H12O6 contains a lot of chemical energy reduced endergonic Reduction of CO2 C6H12O6 proceeds in many small uphill steps each catalyzed by specific enzyme using energy stored in ATP & NADPH AP Biology

From Light reactions to Calvin cycle Calvin cycle chloroplast stroma Need products of light reactions to drive synthesis reactions ATP NADPH AP Biology

Melvin Calvin Melvin Calvin (April 8,1911 – January 8, 1997) The man who unrevealed the mystery of plants growth How did he do it? Nobel prize in Chemistry - 1961 AP Biology

Calvin’s experiment Air Light Light Valve Algae Algae suspension Transparent Flask Hot methanol, for quick killing Algae suspension 14CO2 AP Biology

starch, sucrose, cellulose & more Calvin cycle RuBP Rubisco 1. Carbon fixation 2. Reduction 3. Regeneration of RuBP ribulose bisphosphate ribulose bisphosphate carboxylase used to make glucose G3P glyceraldehyde-3-P PGA phosphoglycerate C C C AP Biology

Calvin Cycle Reactions №1 Carboxilation In this reaction CO2 reacts with RuBP and the compound of 6 carbons is formed. It’s unstable so we receive 2 3-PGA Reaction is catalyzed by RuBisCO Mg2+ ions are needed to activate enzyme AP Biology

Calvin Cycle Reactions №2 Phosphorylation 3-PGA is phosphorylated to 1,3-PGA Energy in the form of ATP is used Enzyme that helps phosphoglycerate kinase №3 Reducement 1,3–PGA is reduced to phosphoglyceraldehyde Reducing powers of NADPH are used Enzyme: triosephosphatedehydrogenase AP Biology

Calvin Cycle Reactions №4 Isomerisation PG aldehyde is isomerized into phosphodehydroxyaceton Enzyme: triosephosphateisomeraze AP Biology

Calvin Cycle Reactions №5 Combining 3-phosphoglycerine aldehyde and phosphohydroxy-aceton unite and fructose-1,6-bisphosphate is born Enzyme Aldolase helps here №6 Dephosphorylation fructose-1,6-bisphosphate to fructose-6-phosphate Enzyme: Phosphotase It is believed that 1 of 6 fructose-6P leaves the cycle AP Biology

Calvin Cycle Reactions №7 Donation Fructose-6-phosphate interacts with PG aldehyde Enzyme: transketolase Coenzyme: tiaminopyrophosphate Result: erythroze-4-phosphate and xylulose-5-phosphate AP Biology

Calvin Cycle Reactions №8 Uniting E-4-P and PG-aldehyde unite to form Sedoheptulose-1,7-bisphosphate Enzyme: Aldolase №9 Phosphor removal Inorganic Phosphor is removed from SH-1,7-bisP and Sedoheptulose-7-phosphate appears Enzyme: Phosphatase AP Biology

Calvin Cycle Reactions №10 Transition The C-2 residue is transited from SH-7-P to the Phosphoglyceraldehyde Two pentoses are formed: xylulose-5-phosphate and rybose-5-phosphate Enzyme: Transketolase AP Biology

Calvin Cycle Reactions №11 Isomerization R-5-P is isomerized to rybulose-5-phosphate Enzyme: rybulosephosphate-isomeraze №12 Transfer X-5-P is transformed to rybulose-5-phosphate Enzyme: rybulosephosphate-epimeraze AP Biology

Calvin Cycle Reactions №13 The End Rybulose-5-phoshpate is phosphorylated to RuBP ATP is used Enzyme: phosphorybulosekinase is near AP Biology

AP Biology

Anatoliy Vasserman Онотоле смотрит на тебя как на равного AP Biology

END, YEA. AP Biology

glucose C-C-C-C-C-C fructose-6P P-C-C-C-C-C-C-P DHAP P-C-C-C G3P C-C-C-P pyruvate C-C-C 2 ATP 2 ADP Remember G3P? glycolysis AP Biology

Glyceraldehyde 3-phosphate (3C) (G3P) Glucose and other sugars Ribulose 1,5-bisphosphate (RuBP) (5C) 3-phosphoglycerate (3C) (PGA) Glyceraldehyde 3-phosphate (3C) Glyceraldehyde 3-phosphate (3C) (G3P) Rubisco Reforming RuBP Reverse of glycolysis Carbon fixation Stroma of chloroplast Carbon dioxide (CO2) 6 NADPH 3 ATP 3 ADP 6 ATP 6 ADP 6 NADP+ 2Pi 1,3-bisphosphoglycerate (3C) 6Pi Calvin Cycle AP Biology

To G-3-P and Beyond! Glyceraldehyde-3-P end product of Calvin cycle energy rich 3 carbon sugar “C3 photosynthesis” G-3-P = important intermediate G-3-P glucose carbohydrates lipids amino acids nucleic acids AP Biology

Rubisco Enzyme which fixes carbon from air ribulose bisphosphate carboxylase the most important enzyme in the world! it makes life out of air! definitely the most abundant enzyme AP Biology

Accounting The accounting is complicated 3 turns of Calvin cycle = 1 G3P 3 CO2 1 G3P (3C) 6 turns of Calvin cycle = 1 C6H12O6 (6C) 6 CO2 1 C6H12O6 (6C) 18 ATP + 12 NADPH 1 C6H12O6 any ATP left over from light reactions will be used elsewhere by the cell AP Biology

Photosynthesis summary Light reactions produced ATP produced NADPH consumed H2O produced O2 as byproduct Calvin cycle consumed CO2 produced G3P (sugar) regenerated ADP regenerated NADP AP Biology

Summary of photosynthesis Where did the CO2 come from? Where did the CO2 go? Where did the H2O come from? Where did the H2O go? Where did the energy come from? What’s the energy used for? What will the C6H12O6 be used for? Where did the O2 come from? Where will the O2 go? What else is involved…not listed in this equation? AP Biology

Supporting a biosphere On global scale, photosynthesis is the most important process for the continuation of life on Earth each year photosynthesis synthesizes 160 billion tons of carbohydrate heterotrophs are dependent on plants as food source for fuel & raw materials AP Biology

The poetic perspective… All the solid material of every plant was built by sunlight out of thin air All the solid material of every animal was built from plant material Then all the cats, dogs, rats, people & elephants… are really strands of air woven together by sunlight! sun AP Biology

Any questions? AP Biology

2006-2007 Thank you for your attention! AP Biology