Ribosomes are like tiny factories in the cell. They make proteins that perform all sorts of functions for the cell's operation.
Where are ribosomes located inside the cell?
Ribosomes are either located in the liquid inside the cell called the cytoplasm or attached to the membrane. They can be found in both prokaryote (bacteria) and eukaryote (animals and plants) cells.
Ribosomes are a type of organelle. Organelles are structures that perform specific functions for the cell. The ribosome's job is to make proteins. Other organelles include the nucleus and the mitochondria.
The ribosome has two main components called the large subunit and the small subunit. These two units come together when the ribosome is ready to make a new protein. Both of the subunits consist of strands of RNA and various proteins.
- Large subunit - The large subunit contains the site where new bonds are made when creating proteins. It is called the "60S" in eukaryotic cells and the "50S" in prokaryotic cells.
- Small subunit - The small subunit really isn't that small, just a bit smaller than the large subunit. It is responsible for the flow of information during protein synthesis. It is called the "40S" in eukaryotic cells and the "50S" in prokaryotic cells.
The main job of the ribosome is to make proteins for the cell. There can be hundreds of proteins that need to be made for the cell, so the ribosome needs specific instructions on how to make each protein. These instructions come from the nucleus in the form of messenger RNA. Messenger RNA contain specific codes that act like a recipe to tell the ribosome how to make the protein.
There are two main steps in making proteins: transcription and translation. The ribosome does the translation step. You can go here to learn more about proteins.
Translation is the process of taking the instructions from the messenger RNA and turning it into a protein. Here are the steps the ribosome takes to make the protein:
- The two subunits join together with the messenger RNA.
- The ribosome finds the correct starter place on the RNA called the codon.
- The ribosome moves down the RNA, reading the instructions on what amino acids to attach to the protein. Every three letters on the RNA represents a new amino acid.
- The ribosome attaches amino acids building up the protein.
- It stops building the protein when it reaches a "stop" code in the RNA telling it that the protein is ready.
- The "rib" in ribosome comes from ribonucleic acid (RNA) which provides the instructions on making proteins.
- They are made inside the nucleolus of the nucleus. Once they are ready they are sent outside the nucleus through pores in the nucleus' membrane.
- Ribosomes are different from most organelles in that they are not surrounded by a protective membrane.
- 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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