Question

The Calvin Cycle is also referred to as the "dark reaction." Why can this terminology be misleading?

A) Because it occurs during the night
B) Because it doesn't involve any chemical reactions
C) Because it takes place in the absence of light
D) Because it is a fast process

Answer 1

The term 'dark reactions' is misleading because it suggests the Calvin Cycle reactions occur in the absence of light, while in reality, they can occur during both day and night, as long as ATP and NADPH are available.

Step-by-step explanation:

The term "dark reactions" when referring to the Calvin Cycle can be misleading because it suggests that these reactions occur in the absence of light or only at night. However, the correct answer is that this naming can be misleading because it implies that the reaction occurs in the absence of light (option C). In fact, the Calvin Cycle, also known as the light-independent reactions, does not require light to proceed but is dependent on the energy (ATP and NADPH) produced during the light-dependent reactions of photosynthesis. The reactions of the Calvin Cycle take place in the stroma of the chloroplasts and can occur during both day and night, as long as ATP and NADPH are available. These reactions power the fixation of atmospheric carbon dioxide (CO₂) into organic molecules such as glucose.