1. The Calvin Cycle The Light-Independent Reactions (Dark Reactions) Reduce CO 2 to sugars 7.10 Pg. 116 Will need to know names of some enzymes/molecules Objective: I can describe and count the overall number of reactants and products involved in the Calvin Cycle while being able to analyze a document with details of the process.

2. Calvin Cycle – General Facts  3 rd and Last stage in photosynthesis  Occurs in Stroma of Chloroplast  ATP + NADPH (from light rxns) power it  Main reactant: CO 2  how many? 6  Main product: glucose (C 6 H 12 O 6 )  The cycle turns 6 times  With Calvin Cycle, ENTIRE process is a type of C 3 photosynthesis  Because first molecule made in Calvin Cycle has 3 carbons

3. Calvin Cycle – Detailed Facts (you need to know)  9 enzyme-catalyzed reactions in a cycle (9 steps)  Will break down into 3 steps 1) Carbon fixation attach carbon atom from gas to organic molecule CO 2 bonds with 5-carbon molecule called RuBP already in cycle (catalyzed by RuBisCO) Forms unstable 6-carbon molecule Breaks down into two 3-carbon molecules PGA

4. Calvin Cycle – Detailed Facts (you need to know) 2) ATP gives energy to… NADPH reduces… each 3-carbon molecule In order to have cycle (return to RuBP), must turn cycle more times Only 2 of 12 (twelve) 3-carbon molecules (G3P) combine to make glucose (6 carbons) 2 2 Cycle turns 6 times Need 6 CO 2 There are 6 C in glucose 6 6 12 10 *Gasp* Can make glucose!? PGA G3P

5. Calvin Cycle – Detailed Facts (you need to know) 3) 10 other G3P (3-carbon molecules) rearrange to make original 6 RuBP Numbers work out: 10 X 3 = 30 6 X 5 = 30 Allows Cycle to continue 6 10 To make each RuBP, requires 1 ATP, so… 6 G3P

6. Calvin Cycle – Detailed Facts Note how this depiction shows only 3 turns, but the numbers work out (often shown this way, because cycle can work) – it’s just that you are not making glucose at the end…only G3P So, this depiction happens TWICE… PGA G3P (you don’t need to know)

7. Calvin Cycle Summary  Breathe in 6 CO 2  Bonds with 6 RuBP (catalyzed by RuBisCO) to make 12 intermediate 3-carbon molecules (PGA)  Energize/Phosphorylated by 12 ATP  Reduced by 12 NADPH  Makes 12 G3P 3-carbon molecules  2 will combine to make glucose  Other 10 will turn back into 6 RuBP by being energized by 6 ATP Totals CO 2 in6 ATP in18 NADPH in12 Glucose out 1 http://www.science.smith.edu/departments/Biology/Bio231/calvin.html http://www.youtube.com/watch?v=o1I33Dgcc_M http://highered.mheducation.com/sites/9834092339/student_view0/chapter39/calvin_cycle.html