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 the 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 a prokaryotic organism.
In spite of having no nucleus, it has nuclear material like the DNA in the cytoplasm.
Archea: This is another unicellular organism belonging to the 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 hence they are eukaryotic cells.
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 as those in higher organisms.
It is involved in the 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 a prominent nucleus.
Examples of these algae include; diatoms, Euglenophyta, Chlorophyta.
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 the nucleus and other factors, the yeast is used to study the cell cycle.
Thus, some unicellular organisms like protozoa and single-celled algae have a nucleus.
However, other unicellular organisms like the bacteria, archaea have no nucleus.