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Introduction to energy

The term process in a biological context can be defined as a natural phenomenon marked by small changes that lead to a particular end. Development and growth are processes to which you have already been introduced. Transport or movement of substances from one place to another is the process that you will be studying in this module. Processes require expenditure of energy-energy that is either stored within the system or that is put into the system from some other source. Energy is the ability to do work; that work can be movement of substances from one place to another. There are two types of energy: potential energy and kinetic energy. Potential energy is stored energy. Electrons have potential energy or energy of position when they move in their orbitals around the atomic nucleus. A bond that holds two atoms together has potential energy. Energy is stored in the bond. Kinetic energy, in contrast, is energy of motion or energy that is expended in performing work. Processes require kinetic energy.

Besides the different types of energy, energy also comes in different forms: chemical energy; electrical energy; mechanical energy; light energy; and heat energy. Each of these forms of energy can do different types of work in the natural and physical world. We will meet some of these forms of energy as we proceed through the Plant Processes unit.