* Energy is lost as heat: Cellular respiration isn't perfectly efficient. A significant portion of the energy from food is lost as heat during the process. This heat dissipates into the environment and isn't available to other organisms.
* Energy is stored in chemical bonds: The remaining energy from cellular respiration is stored in the chemical bonds of molecules like ATP (adenosine triphosphate). When an organism eats another organism, it gets this stored energy.
* Food chains are based on energy transfer: So, while the energy released through cellular respiration isn't directly passed on, the energy *stored* in the consumer's body as a result of that respiration *is* transferred when it's eaten by a predator.
Think of it this way: A lion doesn't eat the heat generated by a zebra's cellular respiration. It eats the zebra's muscle tissue, which contains the chemical energy built up through the zebra's cellular respiration.
Therefore, the energy from cellular respiration indirectly contributes to the food chain by being stored in the tissues of the consumer.
