The Cell
The one-celled organism
amoeba protest |
A single-celled bacteria
of the type: E. coli |
A human red blood cell
|
A plant cell from the leaf
of a poplar tree |
The cell is one of the most basic
units of life. There are millions of different types of cells. There are cells
that are organisms onto themselves, such as microscopic amoeba and bacteria
cells. And there are cells that only function when part of a larger organism,
such as the cells that make up your body. The cell is the smallest unit of life
in our bodies. In the body, there are brain cells, skin cells, liver cells,
stomach cells, and the list goes on. All of these cells have unique functions
and features. And all have some recognizable similarities. All cells have a
'skin', called the plasma membrane, protecting it from the outside
environment. The cell membrane regulates the movement of water, nutrients and
wastes into and out of the cell. Inside of the cell membrane are the working
parts of the cell. At the center of the cell is the cell nucleus. The cell nucleus contains the cell's DNA,
the genetic code that coordinates protein synthesis. In addition to the
nucleus, there are many organelles
inside of the cell - small structures that help carry out the day-to-day
operations of the cell. One important cellular organelle is the ribosome.
Ribosome's participate in protein
synthesis. The transcription phase of protein synthesis takes places in the cell
nucleus. After this step is complete, the mRNA leaves the nucleus and travels
to the cell's ribosome's, where translation
occurs. Another important cellular organelle is the mitochondrion. Mitochondria (many mitochondrion)
are often referred to as the power plants of the cell because many
of the reactions that produce energy take place in mitochondria. Also important
in the life of a cell are the liposome's.
Liposome's are organelles that
contain enzymes that aid in the digestion of nutrient molecules and other
materials. Below is a labeled
diagram of a
cell to help you identify some of these structures.
cell to help you identify some of these structures.
6 CO2 + 6 H2O + energy (from sunlight)
C6H12O6
+ 6 O2
In this way, plant cells manufacture glucose and other carbohydrates that they can store for later use.
Organisms contain many different
types of cells that perform many different functions. In the next lesson, we
will examine how individual cells come together to form larger structures in
the human body.
