Stoichiometric models and MFA with isotopes (10 points). Suppose you have a pathway in which product E can be synthesized by two different routes, as shown below. In this system, A is the substrate, and B,C, and D, are the intracellular metabolites. The five reactions rates are v1 through v5 Pathway without isotopic labeling Pathway with 13C labeling (2) Express the system using matrix notation. (2) At steady-state, which of the following expressions are true? (check all that apply) v1=v2+v5v2=v4v4=v5v5=0 (1) Express rmet in terms of GTT. (5) A steady-state experiment is performed such that A is labeled with 13C. Suppose that A and B are labeled at the 1st carbon atom (C1). E produced directly from B is labeled, but E produced via Reactions 3 through 5 is unlabeled. When rA=2mM/min and the ratio Ejabeled /Eunlabeled=3, what are the steady-state fluxes v1 through v5 in terms of the measured rates and concentrations