Question

How does the absence of light cause the amount of radioactively labeled glycerate 3-phosphate to rise in the experiment?

A) Light activates glycerate 3-phosphate synthesis.
B) Darkness inhibits glycerate 3-phosphate degradation.
C) Glycerate 3-phosphate is not affected by light.
D) Radioactively labeled carbon accumulates during darkness.

Answer 1

The absence of light causes the amount of radioactively labeled glycerate 3-phosphate to rise in the experiment because darkness inhibits glycerate 3-phosphate degradation. G3P molecules are then used to build organic molecules, including carbohydrates.

Step-by-step explanation:

The absence of light causes the amount of radioactively labeled glycerate 3-phosphate to rise in the experiment because darkness inhibits glycerate 3-phosphate degradation. In the light-independent reactions or Calvin cycle of photosynthesis, an enzyme called ribulose biphosphate carboxylase (RuBisCO) catalyzes the conversion of carbon dioxide into glyceraldehyde-3-phosphate (G3P). G3P molecules are then used to build organic molecules, including carbohydrates. In the absence of light, the degradation of G3P is inhibited, leading to its accumulation.