Because they lack a membrane.
Some scientists do not consider ribosomes to be organelles because they lack a membrane that surrounds them, a defining characteristic of organelles. Instead, ribosomes are made up of RNA and protein molecules and are found floating freely in the cytoplasm or attached to the endoplasmic reticulum. They are essential for protein synthesis but are not considered organelles by all scientists.
Ribosomes make proteins for the cell.
Ribosomes are organelles. All cells have ribosomes.
Ribosomes are the tiniest organelles. They make proteins for the cell
In a typical animal cell, the only major organelles not covered by membranes are the ribosomes. Ribosomes are composed of r-RNA and proteins.
Ribosomes produce the proteins needed in a cell
The Ribosomes
ribosomes
ribosomes
ATF
ribosomes are the organelles responsible for constructing proteins in the cell.
Ribosomes are the cell organelles that make proteins. They are located throughout the cytoplasm, as well as on the rough endoplasmic reticulum.