Endoplasmic Reticulum

Endoplasmic reticulum (ER) is another long scientific name for an organelle with the main job of transportation. The ER moves chemical compounds back and forth from the nucleus.

Only cells that have a nucleus also have an ER. This means that animal and plant cells all have ER’s but simple cells such as bacteria don’t have ER’s because their cells lack a nucleus.

Think of the endoplasmic reticulum like a series of very tiny roads, only in the case of the ER, they are actually tubes.

The clear ER tubes travel everywhere in the cell parts. There are some ER that travel to various organelles and others that go to and from the nuclear membrane to the cellular membrane outside.

Wherever the ER goes, it carries various materials to the location where they are needed.

The ER has a Two-Part Job:

The function of the ER is so vast that it is divided into two parts that are connected: The rough endoplasmic reticulum (rough ER) and the smooth endoplasmic reticulum (smooth ER). Each part has a separate role in supporting the nucleus but they also work closely together so that the cell is healthy.

Jobs of the Smooth ER

The smooth ER is mainly a storage area and is made of a network of tubes that work closely together. The smooth surface gives it its name.

It stores steroids and fatty acids and will release them when the cells require them. Another portion of its job includes the ability to break down lipids and carbohydrates into simple molecules.

Once done, it can move them to other parts of the cell. It is responsible for the production of steroids and proteins, maintaining the plasma membranes and all of the pathways so that the molecules move around easily.

Jobs of the Rough ER

The rough ER get its name because it is covered with ribosomes which makes it have a bumpy appearance. The rough ER is really made of many sacs that are flattened.

The main job of the rough ER is in transporting molecules back and forth from the nucleus but it also is responsible for creating and packaging proteins that are sent throughout the cells by vesicles, using the golgi apparatus  Other organelles are responsible when additional packaging and distribution is required.

Rough ER Ribosomes

Ribosomes are rather unusual in that while they are a type of organelle in the cell, they also have the ability to attach themselves to other organelles.

This is what happens with rough ER’s. It’s the ribosomes that actually create proteins and they accomplish this through the creation of long chains of amino acids that they have pieced together.

Once the proteins are made, they are moved into the rough ER in the same way that you would board a train. From that point, the rough ER travels and distributes the proteins to other parts of the cell.

 Fun Endoplasmic Reticulum Facts

  • There are two reason that ER has such a long name: the first part of the name is because “endoplasm” is the inside part of the cell’s cytoplasm. The second part is because “reticulum” really means “fine network.”
  • In Eukaryotic cells, almost 50% of the surface consists of ERs and is the cell’s largest organelle.
  • The ER also goes by other names: rER/RER, Rough ER, gER/GER, Granular ER (like they really need MORE names!)
  • The rougher has its own cytoskeleton that is made of proteins.
  • The smooth ER does have some areas known as “Transitional Endoplasmic Reticulum” (Transitional ER) that are part rough and part smooth.
  • When you take medications the body has to “detoxify” or get rid of the excess chemicals. The smooth ER’s in the liver cells have special enzymes that help the body to get rid of that waste.

Interesting Facts about Biology

  • When we eat bread, chicken, nuts, milk, eggs, and fish, we are consuming the amino acids that our bodies need.
  • Some animals have blank DNA in their chromosomes. These blank areas are called “junk DNA.”
  • Every cell in your body has a complete set of chromosomes.
  • If you had the opportunity to unravel all of the molecules of DNA in your body and put them end-to-end, it would stretch from the earth to the sun many times.
  • We are familiar with people that can’t hear or see, but there are some people that don’t have the ability to smell. This disorder is called “anosmia.”
  • The strongest muscle that you have in your body is the muscle in your jaw that you use for chewing.

Endoplasmic Reticulum Quiz

Now let's test what you have learned!