The two steps in photosynthesis are the light-dependent reactions and the Calvin cycle.
Which of the following is true regarding these two steps?
a
The Calvin cycle converts water molecules into oxygen gas as a byproduct of its reactions.
b
During the light-dependent reactions, carbon dioxide is fixed to produce sugars that form glucose.
c
The light-dependent reactions use ATP from the Calvin cycle, and the Calvin cycle uses energy from absorbed sunlight.
d
The light-dependent reactions take place in the thylakoid membrane, and the Calvin cycle takes place in the stroma.
d
To determine which of the following statements is true regarding the two steps of photosynthesis, you need to understand the processes involved in each step.
a. The Calvin cycle converts water molecules into oxygen gas as a byproduct of its reactions:
This statement is incorrect. The Calvin cycle does not convert water molecules into oxygen gas. Instead, it utilizes carbon dioxide to produce sugars like glucose.
b. During the light-dependent reactions, carbon dioxide is fixed to produce sugars that form glucose:
This statement is also incorrect. The light-dependent reactions do not directly involve the fixation of carbon dioxide or the production of glucose. These reactions primarily involve the absorption of light energy to generate ATP and NADPH, which are used in the Calvin cycle.
c. The light-dependent reactions use ATP from the Calvin cycle, and the Calvin cycle uses energy from absorbed sunlight:
This statement is correct. During the light-dependent reactions, light energy is absorbed by chlorophyll molecules in the thylakoid membrane. This energy is used to produce ATP and NADPH, which are then utilized in the Calvin cycle to produce glucose.
d. The light-dependent reactions take place in the thylakoid membrane, and the Calvin cycle takes place in the stroma:
This statement is also correct. The light-dependent reactions occur in the thylakoid membrane of chloroplasts, where light energy is converted into chemical energy. On the other hand, the Calvin cycle occurs in the stroma, the fluid-filled space surrounding the thylakoid membranes, where carbon dioxide is converted into glucose.
Therefore, the correct statement regarding the two steps of photosynthesis is:
c) The light-dependent reactions use ATP from the Calvin cycle, and the Calvin cycle uses energy from absorbed sunlight.
d
The light-dependent reactions take place in the thylakoid membrane, and the Calvin cycle takes place in the stroma.