Individuals - Anatomy & Physiology

Cells Alive
Cell Structure and Functions


Anatomy and Physiology
Every individual living thing is made of smaller parts. The smaller parts have different functions, but all of the parts work together to enable the individual to live and survive in its environment. The smaller parts are made of even smaller parts, which are made of smaller parts, and smaller parts, until you reach the smallest part of all: the cell. The cell is the basic building block of all living things.

Some tiny organisms, called protists, are made of only one cell. Since the single cell must work alone, it has to do everything to make sure that the organism survives. Protists can not be seen with the human eye. To observe tiny organisms in their microworlds, you can use a microscope.
Microworlds
Extremophiles

Multi-celled organisms are more complex. Different parts have different functions, each part sharing the work and cooperating to make sure that the organism survives.


http://www.life.illinois.edu/plantbio/cell/

In a plant, for example, the cells working together in the roots make sure that the plant gets the water and nutrients from the soil that the plant needs to survive. The cells working together in the leaves make sure that the plant exchanges oxygen for the carbon dioxide that the plant needs to survive. The roots and the leaves work together as a system for the plant to survive.