Do Unicellular Organisms have a Nucleus ?
The answer is “Yes” and also “No”. Some of them have while others don’t
The unicellular organisms include
4. Single celled algae
5. Yeast (Single celled fungi)
Not all unicellular organisms have have nucleus.
For example all the prokaryotic organisms have no nucleus.
Yet they can be unicellular.
Bacteria: Bacteria is a widely distributed unicellular organisms. They have no nucleus and hence called as prokaryotic organism.
In spite of having no nucleus, it has nuclear material like the DNA in the cytoplasm.
Archea: This is anther unicellular organism belonging to prokaryotic family. Similar to bacteria cell, archaea also lack a specific nucleus.
Hence it lacks a distinct nucleus. But, like bacteria it also has the genetic material in the cell cytoplasm.
However, other unicellular organisms like protozoa have a distinct nucleus.
Protozoa: All protozoans are single celled organisms. The examples of protozoa include Amoeba, euglena, paramecium etc.
The nucleus in these protozoans is well developed like higher organisms.
It encloses the genetic material like the DNA inside it.
It also has a nuclear membrane, nucleolus and other features.
It performs the same function like those in higher organisms.
It is involved in transcription of DNA, translation of mRNA and also protein synthesis.
During cell division, the nucleus also divides into two like the rest of the cell.
Unicellular algae: Algae are Another unicellular organism like single celled algae also have a distinct nucleus.
Like bacteria have many similarities but have prominent nucleus.
Examples of these algae include; diatoms, euglenophyta, cholorphyta.
Unicellular fungi: Fungi are multi-cellular organisms. However, there are few unicellular ones.
Yeast is a type of fungi with a single cell. This unicellular organism also has a prominent nucleus. Due to prominence in nucleus and other factors, the yeast are used to study cell cycle.
Thus, some unicellular organisms like protozoa and single celled algae have a nucleus.
However, other unicellular organisms like the bacteria, archea have no nucleus.