Solving problems on matter and energy metabolism in the cell
The problems use the textbook count. Every glucose molecule undergoes glycolysis: 2 ATP and 2 molecules of a three-carbon compound (lactic acid in an animal cell) form. Of the glucose that went through glycolysis, only the molecules that pass into the oxygen stage are fully broken down: each gives an extra 36 ATP, 6 CO₂ and uses 6 O₂; so a fully broken-down glucose yields 2 + 36 = 38 ATP in all. A glucose that does not pass into the oxygen stage leaves only 2 ATP and 2 molecules of lactic acid (in yeast 2 ethyl alcohol and 2 CO₂). In photosynthesis 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂: 1 glucose needs 6 CO₂ and releases 6 O₂; for masses M(CO₂) = 44, M(O₂) = 32, M(C₆H₁₂O₆) = 180 g/mol. Method: identify the stage, write the number of glucose molecules at each stage, multiply by the coefficient and add, and give the answer with units.
“Problem workshop”. Each group writes its own problem (e.g. 6 glucose, 4 fully broken down) and passes it to another; after solving, they re-check ATP, CO₂ and O₂.