The ribosome is like a small factory in a cell. They make proteins that perform all sorts of functions for cell operations. The main task of the ribosome is to make proteins for cells. There are hundreds of proteins that need to be made for cells, so ribosomes need specific instructions on how to make each protein. Where is the ribosome in the cell?
The ribosome lies well in the fluid inside the cell called the cytoplasm or attached to the membrane. They can be found both in prokaryotes (bacteria) and eukaryotes (animals and plants) cells.
Organel
The ribosome is a type of organelle. Organelles are structures that perform specific functions for the cell. The work of ribosomes is to make proteins. Other organelles include the nucleus and mitochondria.
The structure of the ribosome
Ribosomes have two main components called large subunits and small subunits. Both units come together when the ribosome is ready to make a new protein. Both subunits consist of a strand of RNA and a variety of proteins.
1. Large subunits - large subunits contain the locations where new bonds are made when making proteins. It is called "60S" in eukaryotic cells and "50S" in prokaryotic cells.
2. Small Subunit - Small subunits are actually not very small, only slightly smaller than large subunits. It is responsible for the flow of information during protein synthesis. It is called "40S" in eukaryotic cells and "50S" in prokaryotic cells.
3. The letter "S" in the name of the subunit is the unit of measure and abbreviation of the Svedberg unit.
Protein synthesis
The main task of the ribosome is to make proteins for cells. There are hundreds of proteins that need to be made for cells, so ribosomes need specific instructions on how to make each protein. This instruction comes from the nucleus in the form of RNA. Messenger RNA contains special codes that act like recipes to tell the ribosome how to make proteins.
There are two main steps in making proteins: transcription and translation. Ribosomes perform translational steps. How the protein synthesis process will be described in a separate article.
Translation
Translation is the process of taking instructions from messenger RNAs and converting them into proteins. Here are the steps ribosomes needed to make protein:
1. Both subunits join together with messenger RNA.
2. The ribosome finds the correct place starter on the RNA called the codon.
3. The ribosome moves down the RNA, reading the instructions about what amino acids to embed the protein. Every three letters on RNA is a new amino acid.
4. Ribosomes stick to amino acids build proteins.
5. Stop building the protein when it reaches the "stop" code in this RNA saying that the protein is ready.
The function of the Ribosome for the cell
Inside the cell, the ribosome is in two cytoplasmic regions. Some ribosomes are found scattered in the cytoplasm (referred to as free ribosomes), while others are attached to the endoplasmic reticulum (ribosomes bound). Thus, the surface of the endoplasmic reticulum when bound to a ribosome is called a rough endoplasmic reticulum (RER). Both free ribosomes and bound ribosomes have the same structure and are responsible for protein production.
Talking about the main function of the ribosome, they play a role in the assembly of amino acids to form a particular protein, which in turn is essential for carrying out cell activities. As we know about protein production, the first deoxyribonucleic acid (DNA) produces RNA (messenger RNA or mRNA) by DNA transcription process, after which the genetic message of mRNA is translated into protein during DNA translation.
To be more precise about protein synthesis by ribosomes, the sequence for the assembly of amino acids during protein synthesis is determined in mRNA. mRNA is synthesized in the nucleus then transported to the cytoplasm to further perform protein synthesis. In the cytoplasm, two ribosomal subunits bind around the mRNA polymer and the proteins are synthesized with the help of transfer RNA (tRNA), according to the genetic code. This whole process of protein synthesis is also referred to as the central dogma.
Typically, proteins are synthesized by free ribosomes used in the cytoplasm itself, while protein molecules produced by bound ribosomes are transported outside the cell. Given the primary function of ribosomal proteins in the building, it is understandable that cells can not function without ribosomes.
Interesting Facts about the Ribosome
1. The word "rib" on the ribosome comes from ribonucleic acid (RNA) which provides instructions for making proteins.
2. They are made in the nucleoli nucleus. Once they are ready they will be sent outside the core through the pores on the nuclear membrane.
3. Ribosome are different from most organelles because they are not surrounded by protective membranes.
4. The Ribosome was discovered in 1974 by Albert Claude, Christian de Duve, and George Emil Palade. They won the Nobel Prize for their discovery.
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