Question

11. Label this diagram summarizing electron flow in photosynthesis Primary electron acceptor Energy to make Primary electron acceptor Light Light 2H + O 12. An experiment was performed with isolated chloroplasts. The chloroplasts were first made acidic by soaking them in a solution of pH 4. After the thylakoid space reached ph 4, the chloroplasts were transferred to a basic solution at pH 8. The chloroplasts then made ATP even though they were in the dark. a. Explain this result. Use a drawing of the chloroplast in your explanation. The overall goal of photosynthesis in the chloroplast is to make sugar, not ATP.

Answer 1

11. Please follow the attached diagram. The labels are made in red.

PSI PSII NADP+ Primary electron acceptor Energy to make Primary electron acceptor NADPH Light QB Cyt b6f complex H20 P700 P680 OXYGEN EVOLVING COMPLEX 2H + O2

12. a The pH within the thylakoid intially is 7. Upon placing the chloroplast in an acidic solution of pH=4, the pH within the thylakoid changes to 4. Then when the chloroplast is placed in the buffer which has a pH=8, there is a sudden increase in the pH of the stroma. This generates an electromotive force that moves H+ ions from the inner side of the thylakoid membrane to the stroma and in the process converts ADP and inorganic phosphate in the buffer to ATP. This generates a burst of ATP and leads to the disapperance of pH gradient.

b. For generation of glucose plant cells require ATP and NADH which is being produced in the above situation. If these chloroplast have access to a source of carbon like CO2 then they can produce sugar.