The Cell Part II: Ribosomes

Ribosomes are probably the most common organelles in cells. Not only are there many of them within a cell, but they are in every cell in existence, both prokaryotic cells and eukaryotic cells. In the prokaryotic cell, ribosomes will be found floating in the cytosol, which is the fluid taking up space in the cell not left to organelles. In eukaryotic cells, however, most ribosomes are found attached to the endoplasmic reticulum (ER). The area in which they are attached is known as Rough ER. The other ribosomes in eukaryotic cells float free in the cytosol. Ribosomes are also divided into two subunits, a larger one and a smaller one. In eukaryotes there is a 40s and a 60s, subunit, whereas in prokaryotes there is a 30s and a 50s. These subunits are necessary in order for the ribosome to take part in the protein building process.

The ribosome takes part during the last stage of the protein building process, known as translation process. The first step of the process involves the messenger RNA, or mRNA, getting sent out by the cell nucleus. After that, the ribosomes take action and use their two subunits to lock the mRNA in place. Then a transfer RNA, or tRNA molecule, bound with a specific amino acid, attaches itself to the section of the mRNA that is locked by the ribosome. The mRNA strand is slid down by the ribosomes, so another tRNA bound with a specific amino acid can attach itself to the next section of the mRNA strand. When that happens, the first amino acid breaks its bond with the tRNA molecule, and forms a bond with the other amino acid. That first tRNA molecule leaves, and the mRNA strand slides down, ready for the next tRNA molecule to attach itself and have an amino acid form a bond with the second one. The second tRNA molecule leaves, and the process repeats until the mRNA strand is at the end, and a long chain of amino acids is made, hence a protein.

In the end, ribosomes are small, yet important organelles for the creation of protein, which makes up half of the dry weight of each cell. They are not only found in our cells, but every cell in existence, regardless of whether it is prokaryotic or eukaryotic. Ribosomes are vital for the final stage of making proteins, known as the translation process. They are able to do this because of their two subunits, which can clamp together and hold the mRNA, allowing for the translation process to occur. The result of this process is a long chain of amino acids, or a protein. If there were one thing that could be taken from this paper, it is that ribosomes, despite their size, are important for life itself.


This was a bit tricky, but this site and this video helped me out a bit.