How can ATP be produced?

ATP (adenosine triphosphate) can be produced via four different pathways. 

1. Oxidative Phosphorylation - In Oxidative Phosphorylation, the flow of electrons from nicotinamide adenine dinucleotide (NADH) or flavin adenine dinucleotide (FADH) to oxygen, results in the production of ATP. This process is a major producer of ATP in organisms, generating about 26 out of the total 30 ATP molecules produced from glucose. 
2. Glycolysis - Glycolysis involves the anaerobic catabolism of glucose, which results in the conversion of one glucose molecule into two ATP molecules and two pyruvic acid molecules. 
3. Beta Oxidation - In Beta Oxidation, ATP is produced as part of the process during the conversion of lipids into energy. 
4. Aerobic Respiration - Aerobic respiration involves the production of ATP from glucose in the presence of oxygen.