The properties of life such as growth and development, reproduction and interaction with environment can be understood through processes that sustain and express life in its varied forms. Energy processing in all living beings, provide them with the energy required to perform work and maintain the ordered nature of living structures. Life processes such as nutrition, respiration, transport, control and coordination, growth and reproduction help organisms to sustain and spread life.

The humming bird obtains fuel in the form of nectar from flowers stored in the form of chemical energy and uses this energy to power its flight after processing it. The process which transfers a source of energy from outside environment to inside the living being for bio synthesis of its constituent parts is called Nutrition. Digestion is the process by which large insoluble molecules of food are broken down into small, water-soluble molecules, which are absorbed and assimilated by cells.

The process of Metabolism arises out of thousands of reactions that occur within a cell to manage the material and energy resources of the cell. Sugars are converted to amino acids that are linked together into proteins and proteins are dismantled into amino acids that can be converted into sugars when food is digested. Cellular respiration is a process by which sugar glucose and other organic fuels are broken down in the presence of oxygen to carbon dioxide and water. Energy that is released becomes available to do the work of cell such as beating of cilia, transport of substances across membrane and synthesis of polymers. ATP (adenosine tri phosphate) powers cellular work by coupling exergonic reactions to endergonic reactions.

We need a process by which we can transport nutrients, oxygen and water to billions of cells in the body. The main transport system in human beings is the blood circulatory system. The by products which are wasteful and sometimes harmful are removed and discarded by a process called excretion.

Response to the environmental stimuli is an important property of living organisms and the process by which various organs of an organism work together in a systematic manner to produce an appropriate response to stimuli is called coordination. The control and coordination in plants takes place through hormones and in human beings through nervous system as well as hormonal system called endocrine system.

The most important process, which ensures continuity of life on Earth, is called reproduction and the inherited information carried by genes control the pattern of growth and development of organisms. The information content of DNA, the genetic material, is in the form of specific sequences of nucleotides along the DNA strands and the DNA inherited by an organism leads to specific traits by deciding the synthesis of proteins.