Question

To test the hypothesis that a particular plant synthesizes storage lipids by using glyceraldehyde 3-phosphate (G3P) from photosynthesis, a researcher plans to use radiolabeled precursors to track the molecules through the biosynthetic pathway. Which radiolabeled precursors is most appropriate for the researcher to use?

Answer 1

Answer:

Radiolabeled carbon atom in CO2

Explanation:

Photosynthesis is the process by which green plants fix the atmospheric CO2 into glucose. The process includes carbon fixation during which RuBisCo enzyme catalyzes the reaction of CO2 and a five-carbon compound called RuBP to form 3-phosphoglycerate (3-PGA). The 3-PGA enters the reduction phase of the Calvin cycle wherein it is reduced into glyceraldehyde 3-phosphate. Two molecules of glyceraldehyde 3-phosphate make one molecule of glucose.

To test the hypothesis that glyceraldehyde 3-phosphate from photosynthesis is used by plants to synthesize lipids, radiolabeled CO2 must be used. The radiolabeled carbon atom in the CO2 would be fixed in the form of glyceraldehyde 3-phosphate. If the plant uses glyceraldehyde 3-phosphate as a precursor for lipid synthesis, the synthesized lipid molecules would carry the radiolabeled carbon atom.