Question

The difference in charges across the thylakoid membrane provides the energy to make ATP. 15. What are the products of the light-dependent reactions? 16. The light energy from the sun is converted to what type of energy and stored where? 17. How does ATP synthase produce ATP? Light-Independent Reactions/ Calvin Cycle (Dark Reaction): 20990 91 CYCLE Cartonas DOO Depergewond redes Spele alane wide op OUTPUT 1999 dhe Megreren of op 18. Where does the Calvin cycle take place? 19. Before the Calvin cycle begins, where is the energy stored? 20. What happens to CO2 in the Calvin cycle? 21. What are the inputs to the Calvin cycle? Where do they come from? 22. Why are the reactions of the Calvin cycle also called the light-independent reactions?

Answer 1

Ans. 15 )

Products of light dependent reaction are the high energy compound ATP ,NADPH and O2.

When Photosystem II is exited and oxidized by light then it again rereduced by an electron produced by water.

Electrons produced from the water by the water lysis by the help of oxygen evolving complex. This complex break H2O into 2H+ , 2e- and 1/2 O2.

This electrons finally reduce NADP+ to form NADPH.

And cyclic electron transport from fd ( ferridoxin) to cytb6 generate ATP.

Ans. 16)

Light energy from sun in the form of photons is converted into chemical energy ATP & NADPH and further glucose by the Calvin Cycle stored in chloroplast.

Ans. 17)

The asymmetric nature of photosynthetic membrane causes difference in chemical potential.

in chloroplast lumen of thylakoid is highly positive (high proton concentration) and stroma is negative in comparison to thylakoid lumen.

Because electron transfer from H2O to NADPH generate proton motive force and transfers proton from negative side( stroma) to positive side( lumen)

This change in chemical potential the main key to synthesis of ATP.

Protons transfer from lumen to stroma via ATP synthase and synthesises 1 ATP per 4 proton transported via ATP synthase.

Ans 18)

Calvin cycle takes place in the stroma of chloroplast where products of light reactions like ATP and NADPH are used to synthesis carbohydrates.

For each glucose synthesis there is 18 ATP & 12 NADPH are required. In which 6 molecules of Co2  & H2O are combined to form one molecule of glucose.