Tour of the Cell

A tour of the Cell

The cell is the basic unit of life. Some organisms are made up of only one cell like E. Coli, while other organisms are made up of many cells working together, like humans. Cells are capable of very diverse specialized functions. In multicellular animals, cells do everything from absorb nutients to transmit electrical brain signals. Each cell is responsible for it own maintenance as well as any specialized functions it may preform. Cells may contain internal organelles which serve to compartmentalize cellular functions. In the figure below we see a cut away picture of an animal cell which contains many organelles.

Each oragnelle has a specific function associated with it. The functions for the organelles in the figure above are:

Cell Membrane: The cell membrane is a barrier that controls the entry of most substances into the cell. The barrier is made up of ~50% lipids and ~50% proteins. The proteins serve diverse functions including transportation of substances into and out of the cell, communication, and enzymatic activity.
Nucleus: The nucleus is where the cell stores its genetic matierial in the form of DNA. The DNA is organized into chromosomes which are duplicated for cell division. Transcription also takes place in the nucleus as DNA is transcribed into RNA which is then spliced to produce mRNA.
Mitochondria: The miotchondria is the power plant for the cell. It converts the energy stored in carbohydrates, lipids, and amino acids to ATP for the cell.
Golgi apparatus: The golgi apparatus packages and processes macromolecules for secretion from the cell and also for delivery to other organelles in the cell.
Endoplastic reticulm: Membrane proteins and lipids are synthesized in the endoplastic reticulum. After synthesis proteins and lipids are transported via the golgi apparatus. Parts of the endoplastic reticulum have ribosomes attached and and cause it to appear rough.
Lysosomes: Lysosomes are the compost pile of the cell. This is where cellular componets are degraded and where digestion of materials from outside the cell is carried out.
Cytoskeleton: The cytoskeleton acts to support the structure of the cell. It allows the cell to move and can determine the shape of the cell. The cytoskeleton also allows the transport of organelles within the cell, and the separation of the chromosomes in mitosis.