Question

5. During a class discussion, students reviewed their model of photosynthesis after completing several Elodea and BTB (bromothymol blue) experiments.
They noticed that the BTB solution turned from yellow to blue only when Elodea was placed in light. This helped them identify what materials entered and exited the plant system.
The class recorded that the inputs included molecules taken from the air and water, while the outputs included gases released and molecules that provided energy for growth.
They also discussed that the energy for this process came from light, which caused atoms to rearrange.


Select the TWO statements that correctly describe what happens during photosynthesis.

Responses

A. Carbon dioxide and water are inputs that plants use to produce glucose and oxygen.
A. Carbon dioxide and water are inputs that plants use to produce glucose and oxygen.

B. The energy required for photosynthesis comes from the heat of the Sun by warming the leaves which speeds up the reaction.
B. The energy required for photosynthesis comes from the heat of the Sun by warming the leaves which speeds up the reaction.

C. The oxygen atoms in carbon dioxide are released as carbon dioxide gas.
C. The oxygen atoms in carbon dioxide are released as carbon dioxide gas.

D. The process rearranges atoms to create glucose, which stores usable energy for the plant.
D. The process rearranges atoms to create glucose, which stores usable energy for the plant.

E. Energy from sunlight becomes matter that forms part of the glucose molecule.
E. Energy from sunlight becomes matter that forms part of the glucose molecule.
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Answer 1

A and D.

- A is correct: plants use CO2 and H2O to make glucose and release O2.
- D is correct: photosynthesis rearranges atoms to form glucose, which stores chemical energy.

(Incorrect options: B — the energy comes from light photons, not simply heat; C — the O2 released comes mainly from water, not from CO2; E — light provides energy, it is not converted into matter.)