The chemical reaction for photosynthesis is 6 co2 + 12 h2o + light
energy → c6h12o6 + 6 o2 + 6 h2o. if the input water is labeled with a
radioactive isotope of oxygen, 18o, then the oxygen gas released as
the reaction proceeds is also labeled with 18o. which of the
following is the most likely explanation?
(a) during the light reactions of photosynthesis, water is split, the
hydrogen atoms combine with the co2, and oxygen gas is released.
(b) during the light reactions of photosynthesis, water is split, removing
electrons and protons, and oxygen gas is released.
(c) during the calvin cycle, water is split, regenerating nadph from
nadp+, and oxygen gas is released.
(d) during the calvin cycle, water is split, the hydrogen atoms are added
to intermediates of sugar synthesis, and oxygen gas is released.