Causative organism of typhoid is a bacterium Salmonella typhimurium. It is a prokaryote. The causative organism of sleeping sickness is Trypanosoma which is a protozoan. It is a eukaryote. Ribosomes are the granular structures composed of RNA and proteins. They are not surrounded by any membrane and are seen as dense particles under the electron microscope. Ribosomes found in cytoplasm of eukaryotic organisms are 80S and those in cytoplasm of prokaryotic organisms are 70S, where S is the coefficient of sedimentation and is a measure of the density and size of the ribosome.