Smooth vs. Rough Endoplasmic Reticulum: 13 Differences & Example

Smooth Endoplasmic Reticulum vs. Rough Endoplasmic Reticulum (Smooth ER vs.

The smooth endoplasmic reticulum and the rough endoplasmic reticulum are the two types of endoplasmic reticulum that are used to connect membrane-bound channels in the cell cytoplasm into a network.

The ER is an organelle that is surrounded by a membrane and is only found in eukaryotic cells. This ER is made up of network membranes called cisternae.

The ribosomes that are attached to its surface give it a rough look. Rough ER both makes proteins and stores them.

Smooth ER, on the other hand, aids in the storage of lipids and proteins.The main difference between rough and smooth ER is that rough ER has bound ribosomes, but smooth ER does not.

What Is Smooth Endoplasmic Reticulum?

Smooth ER is a type of endoplasmic reticulum where no ribosomes are attached to the surface. But some smooth ERs have surfaces that are held together by ribosomes. We call this kind of ER a “transitional ER.”

Structure of Smooth ER

Most of the time, the smooth ER is linked to the nuclear envelope. There are also tubules, which are found on the outside of the cell.

These tubes branch out to form a network that looks like a reticulum. There can also be areas that get bigger, like sacs. This ER reticulum gives ER more surface area to work with.

Smooth vs. Rough Endoplasmic Reticulum

Functions of Smooth ER

Some specialized cells have a lot of smooth ER in them. In these cells, lipids, phospholipids, and steroids are made by the smooth ER.

In the testes, ovaries, and sebaceous glands, you can find cells that make lipids. Near the smooth ER, you can find transport vesicles that carry lipids and proteins.

The ER sends these vesicles to the Golgi apparatus. In addition to making lipids, smooth ERs also help break down carbohydrates and steroids. They clean the body of alcohol, drugs, and waste products made by the body itself.

Also, they control how much calcium is in muscle cells. Smooth ER, on the other hand, has glucose-6-phosphate in it to turn glucose-6-phosphate into glucose, which is part of gluconeogenesis.

What is Rough Endoplasmic Reticulum?

On the other hand, ribosomes are attached to the surface of the rough endoplasmic reticulum. The ER is in charge of making proteins.

Structure of Rough ER

The ribosomes that stick to the surface of the rough ER determine how it looks. The process of attaching ribosomes to the rough ER is called translocation.

These are not the ribosomes that are always attached to the organelles of the endoplasmic reticulum (ER). They move out and back into the membrane all the time.

The Golgi apparatus is a large sheet of two membranes that is made by the ER. Vesicles with a membrane carry these proteins from the Golgi to the ER apparatus.

Functions of Rough ER

Ribosomes attach to the ER, and in the cytoplasm, a certain protein-nucleic acid complex forms. At the start of mRNA translation, this complex is made. It is part of a protein in the secretory route.

When a ribosome is set free, translation begins. The first 5–30 amino acids tell the cell what to do. The signal recognition particle can find the signal peptide in the growing chain of amino acids (SRP).

The translation is then stopped, and the ribosome complex attaches to the rough ER translocon. The translation process is done over and over again to make the chain of amino acids.

The protein that is being made goes into the RER lumen. Changes that happen after translation are altered even more in the lumen. The signal peptide is removed by an enzyme called peptidase.

After the signal peptide is taken away, the binding ribosomes are sent back into the cytoplasm. Ribosomes that are always linked to the ER are called non-translating ribosomes.

In addition to making and processing proteins, the rough ER also makes lysosomal enzymes and proteins that are part of the membrane. N-linked glycosylation also starts in the rough ER.

Key Differences (Rough endoplasmic reticulum vs Smooth endoplasmic reticulum)

Basis for comparisonRough endoplasmic reticulum (RER)Smooth endoplasmic reticulum (SER)
DefinitionThe rough endoplasmic reticulum is a type of endoplasmic reticulum consisting of flattened sacs, studded with protein-synthesizing particles termed ribosomes on the outer surface.Smooth endoplasmic reticulum (SER) is a type of endoplasmic reticulum consisting of tubular vesicles that lack ribosomes on the outer surface and is involved in the synthesis and storage of lipids.
RibosomesRough ER has ribosomes on the outer surface.Smooth ER doesn’ thave ribosomes on the outer surface.
LocationThe rough endoplasmic reticulum is mostly found around the nuclear membrane.The smooth endoplasmic reticulum is mostly found near the cell membrane.
OriginRough ER is formed from the nuclear membrane.Smooth ER is formed after the shedding of ribosomes from rough ER.
StructureRough ER is mainly composed of cisternae with few tubules.Smooth ER is mainly composed of a network of tubules with few cisternae.
StructureRough ER posses narrow pores below the ribosomes that allow the passage of newly synthesized polypeptides to the cytosol.No such pores are present on the surface of the smooth ER.
RibophorinsRibophorins are present on the surface of the rough ER.Ribophorins are absent on the surface of the smooth ER.
Involved inRough ERs are involved in the formation of lysosomes.Smooth ERs are involved in the formation of spherosomes or oleosomes.
Found inNumerous rough ER is found in lipid synthesizing cells.Numerous smooth ER is found in protein synthesizing cells.
Type of cellRER is mostly found in cells of glands and protein-producing organs.SER is mostly found in cells like muscle cells and nerve cells.
Golgi apparatusRough ER provides proteins and lipids for the Golgi apparatus.Smooth ER provides vesicles for the cis-face of the Golgi apparatus.
FunctionThe rough endoplasmic reticulum is mostly associated with the production, modification, and transfer of proteins.The smooth endoplasmic reticulum is mostly associated with the production of lipids and the storage of calcium ions.
DiseasesDisease like spondyloepimetaphyseal dysplasia is attributed due to the accumulation of misfolded collagen proteins in the RER.Prolonged SER stress might result in the development and progression of many diseases, including neurodegeneration, atherosclerosis, type 2 diabetes, liver disease, and even cancer.

Smooth vs. Rough Endoplasmic Reticulum

Conclusion

People think of the ER as a network of membrane-bound channels in the cytoplasm that are all linked together. Both smooth and rough ER play a role in making and storing macromolecules.

Lipids are produced by smooth ER. They also store lipids and proteins. On the other hand, rough ER makes proteins and stores them.

When ribosomes are attached to the rough surface of the ER, they can make proteins. Because of this, the main difference between smooth and rough ER is whether or not their surfaces have ribosomes.

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