Answer
RIBOSOMES on the ROUGH ENDOPLASMIC RETICULUM
Explanation:
This is the site of protein synthesis usually find attached to the rough endoplasmic reticulum or freely on the cystosol,
When they are attached to the endoplasmic reticulum they appeared as back dots which makes the surface of ER to appear rough, hence the name ROUGH ER. Smooth ER, lacks Ribosomes, and therefore appears smooth,
Ribosomes are made up of PROTEIN AND RNA.
They are 25nm in diameter;when viewed under high magnification, where theymade up of two sub-units the small and large units.
The protein synthesize by the Ribosomes are passed into the sacs of Rough E.R for transportation,
Basically, a complete Ribosomes is refereed to as 70S for prokaryotic ribosomes and 80S for Eukaryotic Ribisomes.This refers to their sedimentation Co-efficient in Svedberg units,the Eukaryotes sediment faster than the Prokaroytes
