Cellular respiration is how we use the glucose from photosynthesis and change it into what we use as food called ATP, or adenosine triphosphate!
It's cool that the two processes work together!
When glucose is broken down in the mitochondria, which is a part of the cell located in the cytoplasm, during aerobic respiration, or with the presence of oxygen, the glucose gets broken down into carbon dioxide, and water which are waste products, and ATP which is what we use as energy!
But using cellular respiration is how all cells obtain energy for themselves, other organisms get their glucose elsewhere. Plants are called autotrophs because we create glucose by ourselves.