1. Metabolism
- It involves every chemical process that takes place within the body. There are two phases of metabolism, namely catabolism and anabolism.
- Catabolism (catabol- = throwing down; -ism = a condition) is the breakdown of complex compounds into simpler building blocks. An example of the catabolic process is glycolysis wherein glucose is broken down into pyruvate.
- Anabolism ( anabol- = a raising up; -ism = a condition) is the process of creating complex chemical compounds out of smaller, simpler parts. An example is Gluconeogenesis: how organisms convert non-carbohydrate precursors into sugars (namely glucose) for catabolic processes.
2. Responsiveness
- It involves noticing a stimulus and reacting to it. It focuses on identifying and responding to changes in the internal or external environment.
- External changes are changes from the outside of the body. An example is when we shiver as our response to cold. When the external temperature is low, our bodies work hard to maintain a constant temperature.
- Internal changes are changes from inside the body. An example is an increase in body temperature when we have fever.
3. Movement
- It is the motion of the whole body, individual organs, single cells, and even tiny structures inside cells.
- Some examples are the movement of our leg muscles when we walk or run (body), the movement of our diaphragms whenever we breathe (organ), when molecules move from one place to another (cell), and various components of the cell, such as secretory vesicles, travel from one location to another to carry out their duties (structures inside cells).
4. Growth
- Is an increase in size, either by increasing the number of cells or by increasing the size of each individual cell
- An example is the growth of body tissues until we reach adulthood. This is done by increasing the number of cells that comprise them. Cells in numerous tissues of the body divide and expand rapidly and mature overtime as they specialize for their particular job in the body.
5. Differentiation
- Is the process through which unspecialized cells transform into specialized cells with distinct structural and functional properties.
- An example of this is the development of a single fertilized human egg (ovum). From an embryo, and then into a fetus, an infant, a child, and finally an adult.
6. Reproduction
- It is the creation of new cells for tissue development, repair, or replacement, alternatively it refers to the creation of a new person
- An example is cellular reproduction where new cells are formed to replace and repair old cells. Another example would be cell division where the formation of a new individual begins with the fertilization of an ovum by a sperm cell to form a zygote, followed by numerous cell divisions and differentiation of these cells.