Ribosomes are small spherical /granular organelle. They may occur freely in the cytoplasm and may be attached to the outer wall of the endoplasmic reticulum. Ribosomes are the protein builders or the protein synthesizers of the cell. They are like construction guys who connect one amino acid at a time and build long chains.
Ribosomes are special because they are found in both prokaryotes and eukaryotes. Ribosomes are found in many places around a eukaryotic cell. You might find them floating in the cytosol. Those floating ribosomes make proteins that will be used inside of the cell. Other ribosomes are found in the endoplasmic reticulum.
Structure: These are spherical and bounded by the double-layered membrane. Mostly they are made of protein.
Function: In ribosome, various amino acids are combined to synthesize protein.