Question

the picture shows the electron transport chain that occurs in the thylakoid membrane of the chloroplast. which of these steps is shown in the picture? a step 5: h+ ions diffuse into the membrane through pigments. b step 1: water molecules split into oxygen and hydrogen atoms. c step 1: oxygen atoms combine with h+ ions to form water molecules. d step 5: excited electrons combine with the electron acceptor, called nadph, to form nadp+.

Explanation:

In the thylakoid membrane during the light - dependent reactions of photosynthesis, water - splitting occurs. The picture shows water molecules ($2H_2O$) being split into oxygen ($O_2$) and hydrogen ions ($4H^+$) by a water - splitting enzyme. This is the first step in the light - dependent reactions where water is oxidized.

Answer:

B. Step 1: Water molecules split into oxygen and hydrogen atoms.