what is cell metabolism

Good question.

Cell metabolism is the process by which individual cells process nutrient molecules (such as sugars). Metabolism has two distinct divisions: catabolism, in which the cell breaks down complex molecules to produce energy, and anabolism, in which the cell uses energy to construct complex molecules (like proteins) and perform other biological functions. Sugars consumed by the organism can be broken down into a less chemically complex sugar molecule called glucose. Once inside the cell, glucose is broken down to make adenosine triphosphate (ATP), a form of energy, through two different pathways.

The first pathway, glycolysis, requires no oxygen to occur. Each reaction in glycolysis is designed to produce some hydrogen ions that can then be used to make energy packets (ATP). The second pathway, called the Krebs cycle (AKA citric acid cycle), occurs inside the mitochondria (an organelle in every cell) and can generate enough ATP to run all the cell functions.

Make sense?