With reference to the following: Eric Jaffe’s seminal paper on culture of human umbilical vein endothelial cells (Jaffe et al., 1973) recommends using supplemented M199 culture medium. The basic medium contains common electrolytes at the following millimolar concentrations: Na+ (164), K+ (5.8), Ca++ (1.26), Mg++ (0.81), Cl- (145), HPO42- (0.78), HCO3- (26.1), SO42- (1.26). It also contains glucose (5.6 mM), amino acids and phenol red (a pH indicator). The recommended supplements (to be added immediately before use) are foetal calf serum (20% v/v) to provide growth factors, penicillin (200 units ml-1) and streptomycin (200 µgml-1) to prevent bacterial contamination, and L-glutamine (2 mM), a labile amino acid that does not survive storage. The RMM of L-glutamine is 146 gmol-1. How much L-glutamine will you need to weigh out to add to 500 ml of your complete medium? Group of answer choices 291 mg 73 mg 146 mg 2.91 g 146 g