Question

examine the diagram of photosynthesis below and use it to help you answer the following question:
question: which of the following statements regarding the transfer of matter during photosynthesis is false?
○ the oxygen (o) in the air we breathe comes from water (h₂o)
○ the carbon (c) in the sugar we eat comes from carbon dioxide (co₂)
● the hydrogen (h) in the sugar we eat comes from water (h₂o)
○ the oxygen (o) in the sugar we eat comes from water (h₂o)

Explanation:

To determine the false statement, we analyze the photosynthesis process:

• Option 1 (Oxygen in air from water): In photosynthesis, water ($H_2O$) is split, and oxygen ($O_2$) is released as a by - product. So this statement is true.
• Option 2 (Hydrogen in sugar from water): Water ($H_2O$) provides the hydrogen atoms that end up in the sugar (glucose, $C_6H_{12}O_6$) during photosynthesis. So this statement is true.
• Option 3 (Carbon in sugar from $CO_2$): Carbon dioxide ($CO_2$) is fixed during the Calvin cycle, and the carbon from $CO_2$ becomes part of the sugar (glucose). So this statement is true.
• Option 4 (Oxygen in sugar from water): The oxygen in the sugar (glucose) comes from carbon dioxide ($CO_2$), not water. The oxygen from water is released as $O_2$ gas. So this statement is false.

Answer:

The oxygen (O) in the sugar we eat comes from water ($H_2O$) (the fourth option in the list of choices)