To test the hypothesis that a particular plant synthesizes storage lipids by using glyceraldehyde 3-phosphate (G3P) from photosynthesis, a researcher plans to use radio labeled precursors to track the molecules through the biosynthetic pathway. Which of the following radio labeled precursors is most appropriate for the researcher to use?
a) 15N- labeled N2, because atmospheric nitrogen is fixed to amino acids by photosynthesis
b) 14C-labeled CO2, because atmospheric carbon dioxide is fixed to carbohydrates by photosynthesis
c) 35S-labeled methionine, because amino acids are incorporated into lips during photosynthesis
d) 32P-labeled phosphate, because lipids are stored in plants as phospholipids