Photosynthesis HL Mrs. Jackie

Draw the structure of a chloroplast About 2-10microm in diameter Include Circular DNA Ribosomes Starch grains Fat droplets grana Inter granal lamella Draw the structure of a chloroplast

Photosynthesis consist of light dependent and light independent reactions

Light dependent rx and photophosphorilation Energy level X y 2e- NADPH NADP +H 2e- 2e- ADP +Pi ATP 2e- Non-Cyclic Photophosphorilation ADP +Pi ATP 2e- light H2O 2H++1/2O2 PSI light PSII Light dependent rx and photophosphorilation

Non cyclic photophosphorylation Light hits the pigments on PSII which are mainly found in the grana Chlorophyll a involved absorbing light at the 680nm Light absorption excites the electron which move to electron acceptor X. Chlorophyll mol change to a positive because it looses e-. The electrons are passed thorough a series of redox reactions to PSI Non cyclic photophosphorylation

Non cyclic photophosphorylation The presence of Chl a+ induce the lysis of water so that oxygen, H and electrons are released Electrons are taken by Chl a+ which turns into Chl a The oxygen is released as a waste product The H are pumped to the lumen of the grana and accumulate until diffusion occurs though the channel of the APT synthethase and ADP +Pi are converted into ATP Non cyclic photophosphorylation

Grana Thylakoid membrane light 2e- H2O 2H+1/2O2 H+ NADP+H 2e- H+ Lumen ATP Grana Thylakoid membrane ADP+ Pi

Non-cyclic photophosphorilation The light also hits the photosystem I which absorbs light at 700nm. Electrons move away from the nucleus. Electrons move away from chl a to the electron acceptor Y Electron are then passed on to NADP which combines with H to produced NADPH The chl a+ receive electrons from the electron carrier chain and become chl a Non-cyclic photophosphorilation

Cyclic photophosphorilation Increasin energy level X 2e- 2e- light 2e- ADP +Pi ATP 2e- ADP +Pi ATP PSI Cyclic photophosphorilation

Light independent reactions Calvin Cycle Takes place in the stroma of the chloroplast ATP provides energy and NADPH provides the reducing power needed for biosynthesis using CO2 RuBP- carbon dioxide acceptor Light independent reactions

Calvin Cycle 6ATP 6ADP +6Pi 6 Glycerate-3-phosphate 3CO2 (GP) (6x3C) 6 Glycerate-1,3-diphosphate (6 x 3C) RuBP carboxylase 6NADPH 6NADP+ 3 Ribulosebiphosphate (RuBP) (3x5C) 6 triose-phosphate (TP) (6 x3C) 3ADP+3Pi 3ATP 5 Triose-phosphate (TP) (5x3C) Calvin Cycle 1TP (1x3C

The Calvin Cycle takes place in the stoma of the chloroplast. RuBP take up CO2 with the aid of RuBP carboxylase forming GP (glycerate 3 phosphate) GP will be reduced to TP (triose-phosphate) but this conversion needs energy from ATP and reducing power from NADPH. TP can be converted to glucose, sucrose, starch, fatty acids and amino acids TP is also converted to RuBP to keep the cycle going. This process requires ATP Review of Calvin Cycle