Question

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.

Answer 1

Answer:A

Step-by-step explanation:

The light phase reaction involves the photolysis of water. Sunlight splits water up and the hydrogen released combines with carbon IV oxide to form glucose while the oxygen is released to the atmosphere. These processes take place via a series of complex mechanism and biochemical pathways to give the expected products.

Answer 2

B. During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released.

Step-by-step explanation:

In Photosynthesis two phases occurs. They are grouped into light dependent and light independent phase (dark phase) reactions. In the light dependent phase, sunlight is trapped by chlorophyll and water is split into its components ( oxygen, hydrogen ions and free electrons; photolysis). Part of the electrons and the hydrogen ions are picked up by NADP (Nicotinamide adenine dinucleotide phosphate) converting it to NADPH and part of the electrons are used to replenished the photosystems trapping the sunlight.