Ribosomes Function

Ribosomes are tiny but powerful structures found in all living cells. They are responsible for making proteins, which are essential for a cell’s survival and function. Proteins do many jobs in the body, like building muscles, carrying oxygen, and helping chemical reactions happen. Because of this, ribosomes are often called the “protein factories” of the cell.

Ribosomes can be found floating freely in the cytoplasm or attached to the endoplasmic reticulum, forming what’s called the rough ER. Whether free or attached, all ribosomes do the same job—reading instructions from the cell’s DNA (through a molecule called messenger RNA, or mRNA) and using those instructions to assemble proteins from amino acids. Each protein must be made in the correct order, or it won’t work properly.

Even though ribosomes are not surrounded by a membrane like other organelles, they are still very important. Ribosomes are made of two parts, called subunits, which come together only when it’s time to build a protein. These subunits are built in the nucleolus and then travel out into the cytoplasm.

All cells, from simple bacteria to complex plant and animal cells, have ribosomes. Cells that need to make a lot of proteins—like muscle cells or pancreas cells—have thousands of ribosomes working at once.

Fun Fact: A single human cell can have up to 10 million ribosomes, all working hard to build proteins every second!