Calvin Cycle

Question 1

Where does the light independent reaction occur

Answer 1

The stroma

Question 2

Outline light independent reaction

Answer 2

-CO2 enters leaf through stomata and is added to 5 carbon RuBP by enzyme RuBisCO in carbon fixation (converting inorganic carbon into an organic form)
-the unstable 6 C compound quickly breaks down into two molecules of glycerate 3-phosphate(GP) with 3 C
-the hydrolysis of ATP (from LDR) provides energy to turn 3C (GP) into a dif 3C compound glyceraldehyde 3-phosphate (GALP) which also requires H+ ions (from reduced NADP from LDR), reduced NADP recycled to NADP
-some GALP converted into useful organic compounds eg glucose with two molecules of GALP used to make a hexose sugar (eg glucose)
-however 5 out of 6 molecules of GALP produced are used to regenerate RuBP which uses rest of the ATP produced by LDR

Question 3

How many cycles must occur to make one glucose molecule

Answer 3

6 cycles to produce 12 GALPs, 2 of 12 removed to make glucose and other 10 recycled to make RuBP. As each cycle fixes one carbon atom (from CO2), glucose has six so six cycles