The Krebs or Citric Acid Cycle is common stumbling block for high school biology students across the USA. Most diagrams are bat-poo crazy for interpretation. They often look more like schematics for information flow or something like an astrological table reading. Nonetheless, here is a simplified version made with items that people are more adept to understand.
Basically the dice represent the carbon compound being cut down. Likewise familiar Nintendo items that relate to power ups have been added where most kids and people under 55 will understand.
In order to "PLAY" the "Cellular Respiration Game" you need to deposit a "25¢ Pyruvate Coin" into the system and you will get a bunch of power ups, which are represented by the 1up green mushrooms, enlarge red mushroom, and fire flower. Also note that the cycle consumes one drop of water, right after you get the enlarge red mushroom.
Enjoy!
PS. Oh year there is the Mario Star flag on the right, as this is a flag blog after all. And if this doesn't help see maybe the awesome Amoeba Sisters can help?