How would you explain the connection between glucose entering the body and energy created by the body to a friend, using your new biochemistry knowledge?

Glucose can enter the body through the mouth. It does not need to be digested, but it can be absorbed directly. From the stomach, glucose is carried away by the blood stream. Then it is absorbed by the arteries to arterides to capillaries where it leaves the blood stream to go directly into a cell.
Cellular respiration allows organisms to use energy store in the chemical bonds of glucose (C6H1206). The energy in glucose is used to produce ATP. Cells use ATP to supply their energy needs. In respiration, glucose is oxidized and thus releases energy. Oxygen is reduced to form water. The carbon atoms of sugar molecule are released as carbon dioxide. The complete brakedown of glucose to carbon dioxide and water reqires two major steps: 1) glycolysis 2) aerobic respiration.
Glycolysis occur in the cytoplasm and does not require oxygen. There are ten steps in glycolysis and each one is catalyzed by a specific enzyme. In the end of the glycolysis 2 ATP molecules are produced.
The aerobic respiration requires oxygen and yields more energy. Aerobic respiration is divided into two processes, the krebs cycle and the Electron transport chain, which produces ATP through chemiosmotic phosphorylation. The aerobic respiration can produce 34 or more ATP if oxygen is present.

Ref Work

Campbell,M;Farrell,S. Biochemistry 7th edition.