Question

question 20
the electrons of photosystem ii are
a. attach to carbon atoms in the light reaction
b. replaced by electrons from photosystem i
c. are released into the atmosphere as a byproduct
d. produce o 2 molecules which are released
e. are replaced by the splitting of water molecules (photolysis)

Explanation:

• In photosystem II, during the light - dependent reactions of photosynthesis, water molecules are split (photolysis).
• The splitting of water molecules provides electrons to replace those lost from photosystem II.
• Option a: Electrons in the light reaction are not directly attached to carbon atoms. Carbon fixation occurs in the Calvin cycle (light - independent reactions).
• Option b: Electrons lost from photosystem II are not replaced by electrons from photosystem I. Photosystem I gets its electrons from the electron transport chain that follows photosystem II.
• Option c: The by - product released from the splitting of water (related to photosystem II) is oxygen, not electrons.
• Option d: The production of \(O_2\) is a result of water splitting (to replace electrons in photosystem II), but the main point about electron replacement is more relevant here.
• Option e: This is correct as the splitting of water (photolysis) replaces the electrons of photosystem II.

Answer:

e. are replaced by the splitting of water molecules (photolysis)