Biochemistry is the study of mechanisms of life at the molecular level. Thus, knowledge of this subject has become an indispensable tool to biologists. Biochemistry mainly deals with the reactions involved in the degradation of food substances which provide the energy required by organisms to survive. Some of the major topics covered as part of this subject are principles of chemistry and physics, structure and function of macromolecules such as proteins, carbohydrates, lipids and nucleic acids, enzymes and enzyme kinetics, biochemistry and function of micronutrients and vitamins, and metabolism of carbohydrates, lipids and proteins. In addition, molecular genetics, molecular cell biology and immunology are also covered.