The Cell

The fundamental unit of life is the cell.  Without at least 1 cell, an organism can’t live.  Even you and I started out as a single cell at one point.  So I present another artistic masterpiece, an animal cell I drew just for you.

As you see the cell is labeled an Animal Cell.  There are many types of cells and this is what a generic animal cell looks like.  Muscle cells and nerve cells will have a different look, but will have the same parts.  Likewise, cells of plants are similar, but not identical to animal cells.  And bacteria cells are even more different!  But since we’re animals, we’ll start with the animal cell.

You can think of the cell like a little city.  Every part inside of the cell has a purpose; it’s there to do a job.   The parts that make up a cell are called organelles.  Here are some of the important cell parts and their jobs:

Cell membrane – like the walls of a castle, the cell membrane allows in things that are needed (like food) and allows out things that aren’t needed (like waste).  The cell membrane is the cell’s first line of defense to keep unwanted intruders out (like viruses!).

Cytoplasm – sort of like jelly, the cytoplasm is the cell’s internal environment and keeps the organelles from bumping into each other.

Endoplasmic reticulum (E.R.) – specific jobs vary from one cell type to another, but ultimately helps with transport of proteins, much like a conveyor belt.

Golgi apparatus – modifies and transports proteins from the E.R., as well as creation of lysosomes and transport of lipids.  The Golgi apparatus is like a factory, it builds and ships.

Lysosome – these sacs are full of enzymes for digesting food that come into the cell.

Mitochondrion – like power plants, the mitochondria turn sugar into energy that’s usable by the cell.  Your house uses electricity, the cell uses a molecule called ATP.

Nuclear envelope – is like a second wall around the nucleus.  Just like the King has a second set of guards closer to him, the nuclear envelope is even more selective than the cell membrane, and not much gets through.  There are holes in the nuclear envelope and usually only nucleic acids and some proteins are allowed in and out.

Nucleolus – primarily makes ribosomes.  That’s all you need to know!

Nucleus – the mayor’s office of the cell.  Everything that happens in the cell is ultimately controlled by the nucleus and the DNA inside.   The lack of a nucleus is a easy way to tell that the cell you’re looking at is a prokaryote.

Ribosome – take amino acids and make proteins.  It’s like a little machine that runs nonstop until it reaches the end of its job!  There’s a neat little animation on Wikipedia.