Describe the light and dark phases of photosynthesis according to the plan: 1) the place of flow; 2) starting materials; 3) ongoing processes; 4) end products. What products of the light phase of photosynthesis are used in the dark phase?
Light phase of photosynthesis.
1) Place of occurrence: thylakoid membranes.
2) Starting materials: Н2О, oxidized NADP (NADP +), ADP, Н3РО4. For the flow of the light phase, photosynthetic pigments (chlorophylls, etc.) are also necessary, but they cannot be called the starting materials of the light phase.
3) The processes that take place: light absorption by photosystems, photolysis of water, electron transport to the outside of the thylakoid and the accumulation of protons inside the thylakoid (i.e., the appearance of an electrochemical potential on the thylakoid membrane), ATP synthesis, NADP + reduction.
4) End products: ATP, reduced NADP (NADP • N + H +), by-product molecular oxygen (O2).
The dark phase of photosynthesis.
1) Place of occurrence: chloroplast stroma.
2) Starting materials: CO2, ATP, reduced NADP (NADP • Н + Н +).
3) Occurring processes: glucose synthesis (reduction of CO2 to organic substances), during which hydrolysis of ATP and oxidation of NADP • H + H + occur.
4) Final products: glucose (С6Н12О6), oxidized NADP (NADP +), ADP, Н3РО4.
In the dark phase of photosynthesis, such light phase products as NADP • Н + Н + (serves as a source of hydrogen atoms for glucose synthesis) and ATP (serves as an energy source for glucose synthesis) are used.