A long time ago before the dinosaurs there were 3 orphans and 1 dog.  These orphans were named Glycolysis, krebs cycle, and Electron transport chain.  The Dog's name was Photosynthesis. Each person in this family had a special job, even Photosynthesis.

carbon dioxide + water light glucose + oxygen + water

6CO2 + 6H2O light C6H12O6 + 6O

chemical equation for photosynthesis

during the light dependent reaction sunlight and water enters the chloroplast and into the thylakoid. The thylakoid produces ATP and NADPH. While that is happening, oxygen, which is a waste product, is released.

Photosynthesis had a very important job of making glucose (C6H12O6).  His job was in a place called Chloroplasts. Photosynthesis would make glucose by taking carbon dioxide (CO2), water (H2O), and sunlight and go through the very complicated process of turning all his ingredients into glucose, and oxygen (O2).

High energy electrons

The high-energy electrons produced by chlorophyll are highly reactive and require a special carrier. An electron carrier is a compound that can accept a pair of high-energy electrons and transfer them to another molecule with most of their energy. NADPH can carry the high-energy electrons that are produced by light absorption in chlorophyll to chemical reactions elsewhere in the cell.

The H in NADPH is hydrogen. The hydrogen ions freed by the breakdown of water molecules flow through an enzyme called ATP synthase. ATP synthase changes ADP to ATP

cellular respiration is a process that takes place in cells in the mitochondria to convert biochemical energy from nutrients into ATP.

After photosynthesis did his job glycolysis could start his job. Glycolysis had the job of using the glucose that photosynthesis made and use it to make pyruvic acid.  But to make this pyruvic acid Glycolysis had to take two ATP molecules and put the glucose into a complicated process that cause the glucose into pyruvic acid and a total of 4 ATP.

Then after Glycolysis finished his job Krebs Cycle could start her job.  Krebs had the hard job of taking the pyruvic acid that Glycolysis made and using it to make carbon dioxide, NADH, ATP, and FADH2. Because glycolysis produces 2 molecules of pyruvic acid from each glucose molecule, the krebs cycle turns twice for each glucose molecule that enters glycolysis.