The cytoplasm is a watery substance that fills up the inside of the cell. It is filled with organelles, enzymes and molecules that the cell will need or has already used. The cytoplasm is important to the cell because most of the molecules and organelles (mini organs) don't have legs to walk around the cell. The cytoplasm provides them with a means to slip and slide around. You might think - "Where does a molecule or organelle need to go anyway?" In order to carry out their very important and very specific jobs, organelles need the proper supplies - proteins, ATP and oxygen to name a few. Without these things, the organelles couldn't do their jobs and the cells would die.
The organelles that you should know a little bit about are:
You also may want to visit the Cell Membrane.
The Nucleus:
Command CentralThe nucleus is the biggest and most important organelle in the cell. It contains the mission instructions for the whole cell. The mission instructions are written on your chromosomes and genes. They specifically state how proteins are supposed to be made. Since proteins make up parts of our cell membranes, our enzymes and our muscles, they are very important to our ability to live. If we started making the wrong proteins or put proteins together incorrectly our bodies would be in big trouble.
In order to protect the genes and chromosomes, the nucleus is surrounded by another mini cell membrane.
Ribosomes:
The Protein MakersRibosomes not only make proteins, but they are also made out of proteins. Ribosomes are tiny little organelles, often shown as a ball in pictures. Many times, ribosomes attach to a huge organelle called the endoplasmic reticulum, which will process and store some of the proteins that the ribisomes make.
Endoplasmic
Reticulum: A Big Old WarehouseThere are two kinds of Endoplasmic Reticulum (ER): smooth and rough. They are very easy to tell apart. The rough ER has ribosomes all over it like barnacles on a boat. The smooth ER doesn't.
Rough ER functions to process and store proteins. It is similar to a detail shop. If you want pin stripes, tinted windows, and white wall tires on your protein, it needs to go to the ER. If you prefer the simpler molecule, you can get a basic protein from the ribosome. The ribosome just reads the instructions that appear as the protein is being built and figures out whether the protein needs to be customized in which case it zips over to the rough ER.
Smooth ER has nothing to do with proteins, after all it has no ribosomes. The smooth ER has its own jobs such as synthesizing lipids, breaking down carbohydrates, and detoxifying poisons that get into your body.
The ER is quite large- so that it can have lots of proteins and lipids and drugs all being processes at one time.
Golgi Apparatus:
The Postal Service of the CellThe Golgi Appartus is the shipping center of the cell. It packages, labels, inspects, and perfects proteins and other molecules. Many of the molecules that reach the Golgi will be shipped out of the cell and need to know where they are going. So the Golgi labels them. Not only that, but the Golgi has a system of postal workers, called vesicles that will pick up packages from the ER and take them to the edge of the cell membrane after the Golgi's work is done.
Lysosome:The
EnforcerEven in a place as small as a cell, we need someone to pick up the bad guys. But unlike the police, these lysosomes literally chew somebody up and spit them out. Lysosomes pick up foreign invaders, food and old organelles and break them into small pieces that can hopefully be used again. If they pick up a really bad invader, they will chew it up and spit what is left of him right out of the cell so that he can be removed from the body.
The lysosome is able to do this because it is filled with enzymes (proteins again). The enzymes are specially made for the lysosome and work only at a low pH - highly acidic - conditions. The reason for this is that the enzymes are so strong that they could eat the whole cell if the lysosome ever let them out. But because they can work ony at a low pH and the rest of the cell has a neutral pH, they cannot work in the rest of the cell, even if they escaped from the lysosome.
The Mitochondria:
The Electric CompanyYou will learn more about what happens in the
mitochondria when you read about cellular respiration, but it
is important to know that all the nergy in the cell comes from
the mitochondria. Remember in the cell membrane, how some proteins
need ATP to let molecules into or out of the cell? All of that
ATP comes from the mitochondria. Remember how enzymes need ATP
to start up a reaction? That ATP comes from the mitochondria too.
The mitochondria provides energy for the whole cell to run. Without
the mitochondria, the whole cell would be in a permanent black
out.