Unicellular organisms are those organisms which are made of only one cell (uni = one). Some unicellular organisms are:
Bacteria
Archaea
Protozoa
Unicellular fungi
Unicellular algae
Almost all of the unicellular organisms are so small in size that we have to use a microscope to see them. Some exceptions are giant algae and a couple of types of bacteria (for example Thiomargarita niambiensis).
Bacteria are classified as prokaryotic unicellular organisms. Prokaryotic cells are those which do not contain a 'true' nucleus (as opposed to eukaryotes which do; eu means true). This means that their genetic material is not packed into a proper membrane bound nucleus. Also, they do not have any other membrane bound organelles within them either like golgi apparatus etc.
Bacteria
Archaea
Protozoa
Unicellular fungi
Unicellular algae
Almost all of the unicellular organisms are so small in size that we have to use a microscope to see them. Some exceptions are giant algae and a couple of types of bacteria (for example Thiomargarita niambiensis).
Bacteria are classified as prokaryotic unicellular organisms. Prokaryotic cells are those which do not contain a 'true' nucleus (as opposed to eukaryotes which do; eu means true). This means that their genetic material is not packed into a proper membrane bound nucleus. Also, they do not have any other membrane bound organelles within them either like golgi apparatus etc.