* Very small: Ribosomes are indeed incredibly tiny, measuring only about 20-30 nanometers in diameter.

* Not bounded by a membrane: Unlike many other organelles like mitochondria or the Golgi apparatus, ribosomes lack a membrane surrounding them.

* Consist of large subunit: Ribosomes are made up of two subunits, a large subunit and a small subunit.

Function of ribosomes: Ribosomes are responsible for protein synthesis. They read the genetic code carried by messenger RNA (mRNA) and use it to assemble amino acids into proteins.

Let me know if you have any other questions about organelles!