Ribosomes are small and dense organelles in cells and function as a site for protein synthesis. Ribosomes are found in the cytoplasm and attached to the endoplasmic reticulum (ER) membrane during the process of protein synthesis. If the protein synthesis procedure does not work, ribosomes will form small subunits and large subunits.
Apart from that, ribosomes are also cell components that form proteins from all amino acids. Ribosomes have a diameter of about 20 nanometers and consist of 65% ribonucleic acid (RNA) or ribosomal ribonucleic acid and 35% ribosomal protein.
Cells with high protein synthesis mobility have many ribosomes, for example liver cells in the human body have several million ribosomes. Ribosomes on the other hand are composed of various proteins and several RNA molecules.
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Animal cells (Kelvinsong/Creative Commons CC0 1.0 Universal Public Domain Dedication).
In general, animal cell components consist of:
- Nucleolus.
- Cell nucleus.
- Ribosomes (small dots as part of number 5).
- Vesicles.
- Rough endoplasmic reticulum.
- Golgi body.
- Cytoskeleton.
- Smooth endoplasmic reticulum.
- Mitochondria.
- Vacuoles.
- Cytosol (fluid containing organelles consisting of cytoplasm).
- Lysosomes.
- Centrosome.
- Cell membrane.
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Ribosomal Structure
The structures that make up ribosomes are protein and RNA. Each ribosome is then divided into two protein and RNA subunits, namely small and large subunits.
The location of the RNA and protein subunits on the other hand is on top of each other with the entire large subunit being on top of the small subunit. Furthermore, in the middle of the two subunits there is also more RNA. This is what forms new ribosomes and makes up cell organs.
As reported on the Science Center website , the two subunits in the ribosome will come together when the ribosome is considered ready to assemble a new protein. The two of them will also come together and form a sequence consisting of RNA and various proteins.
One thing that must be known next is that each subunit has its own function and task. The small subunit functions as a reader of messages initially conveyed by messenger RNA (mRNA) in amino acids. Meanwhile, the large subunit has the task of forming peptide bonds in the ribosome.
According to Yuwono (2002), there is a place that makes new bonds in the large subunit of the ribosome. The formation of new bonds will later produce new proteins. Meanwhile, the small subunit will convey information when the protein synthesis process is underway.
Based on the composition of eukaryotic and prokaryotic cells, each ribosome structure has its own coefficient value. The small subunit in eukaryotic bodies has a sedimentation coefficient value of 40S Svedberg units, while the large subunit has a value of 60S Svedberg units. However, the sedimentation coefficient value for eukaryotic bodies is 80S Svedberg units if taken as a unit.
Meanwhile, the small subunit in prokaryotic organisms has a sedimentation coefficient value of 30S Svedberg units, while the large subunit has a sedimentation coefficient value of 50S Svedberg units. However, if the two sedimentation coefficient values are combined, they will reach 70S Svedberg units.
As previously known, the components of ribosomes are protein and RNA. One important thing to note is that the RNA that makes up ribosomes must consist of ribosomal ribonucleic acid (ARNr). When the protein synthesis process takes place in the ribosome, there will be other ARNs involved, namely the ambassador ARN (ARNd) and the transfer ARN (ARNt) which are attached to the ribosome.
The two ARNs also have their respective roles. The transfer ARN functions to supply various kinds of amino acids which will later be processed into protein. Meanwhile, the ambassador’s ARN functions to convey genetic information about proteins that must be carried out in the synthesis process.
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Ribosomes Shape and Size
After understanding the meaning and structure of ribosomes, you also need to know the size and shape of the cell organs in the body. The shape and size of the ribosome actually depends on its location.
As explained above, ribosomes are located between two cells, namely prokaryotic and eukaryotic cells. So, the function of ribosomes in the two places also has different sizes and shapes.
1. Eukaryotes
Eukaryotic ribosomes are ribosomes found in eukaryotic cells. These ribosomes have a free location in the cytoplasm and are generally bound to the endoplasmic reticulum.
Meanwhile, the size of the eukaryotic ribosome itself ranges from 32 x 22 nanometers with a weight of 4,220,000 daltons. The combined value of the sedimentation coefficient of eukaryotic ribosomes is 80S. This causes eukaryotic ribosomes to consist of 40% RNA and around 60% protein.
2. Prokaryotes
Slightly different from eukaryotic ribosomes, prokaryotic ribosomes are cell organs that are basically located in the cytoplasm. These ribosomes have subunit sizes with sedimentation coefficients of 30S and 50S. Meanwhile, the size of this cell organ ranges from 29 x 21 nanometers with a weight of 2,520,00 daltons.
Ribosomal Function
Ribosomes can be found in plant and animal cells. Of course, each cell also has a function and role in life. As explained above, the function of ribosomes is as a cell organ that supports the process of preparing proteins in the cell or often called protein synthesis.
Ribosomes consist of two different subunits. This is what causes the function of ribosomes to be more inclined towards the translation process than the cell transcription process.
Cells in the body must carry out the protein production process which aims to speed up the biological processes the body goes through. Apart from that, the proteins produced by ribosomes also play a role in supporting the body’s biological processes so that they continue to function properly.
The reason is that protein is a very essential part of various body organs, such as hair, skin and nails. If there is no protein in that area as a result of ribosome function, of course many other body functions will be disrupted.
Ribosomes have a very essential role in every metabolic activity. This is because ribosomes also act as collectors of amino acids to be prepared into certain proteins. The process of forming proteins is an important aspect of cell organs.
Ribosomes can form proteins that will later be used in the cell as well as proteins to be released by the cell.
Basically, the proteins in the cell are made by ribosomes in the cell cytosol. Meanwhile, proteins outside the cell are usually produced by ribosomes from the endoplasmic reticulum and nuclear envelope.
That’s an article related to “ribosome structure in living things” which you can use as reference and reading material. Hopefully all the discussion above is useful for you, OK? Also share this article on social media accounts so that your friends can also get the same benefits.
Reference
- Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2002). Molecular Biology of the Cell (4th ed.) . New York: Garland Science. ISBN 978-081-5332-18-3.
- Champe P.C., Harvey R.A., & Ferrier D.R. (2005). Lippincott’s Illustrated Reviews: Biochemistry. Philadelphia: Lippincott Williams & Wilkins. ISBN 978-078-1722-65-0.
- Irawan, B. (2019). Genetics: Explanation of the Mechanisms of Inheritance of Traits . Surabaya: Airlangga University Press. ISBN 978-979-1330-76-3.
- Yuwono, T. (2002). Molecular Biology . Jakarta: Erlangga. ISBN 978-979-7811-92-1.