In this activity, students will apply their knowledge of basic chemistry to logic their way through the energy transformations occurring in cellular respiration. The first part of the activity displays the glycolysis and pyruvate processing pathways with a simplified version of carbon intermediates. Students will have to work in their groups to figure out the steps and energy carrying molecules involved between each of the carbon intermediates by considering the change of bonds, hydrogens, carbons, and phosphates between each molecule. The second part of the activity is similar with an unfinished diagram of the Kreb’s cycle. For this part of the activity, the diagram includes carrier molecules, water, and CO2 products that leave the cycle, but the simplified carbon intermediate pictures need to be match to the correct step in the cycle. Students use the products of the Kreb’s cycle to figure out where to place the carbon intermediates. This activity will help students visualize how glucose can be broken down to produce energy carriers like NADH and ATP the source of CO2 products. This activity helps address a common question from students, “where does NADH, ATP, and CO2 come from?”