Difference Between Multicellular and Unicellular
Cells are the building blocks of life of an organism. All living things have cells. Interestingly, there are animals including human beings which are built up of millions of cells while there are organisms which are built up of a single cell. That is why living things are classified as unicellular and multi-cellular. There are a lot of differences between unicellular and multi cellular creatures.
Unicellular organisms are single cell creatures which are small in size. They are very simple creatures. They are categorized as Prokaryotes because of their simple structures. They are not visible by human eye. Cell membrane is not present in them. They are generally found in an environment which is not suitable for multi cellular creatures. For example they may be found in radioactive and acid environment. Different types of organism structures are the result of a long evolution of unicellular structures. Bacteria, amoeba, paramecium and yeast are the examples of unicellular creatures.
Multi cellular Organisms
The creatures having more than one cell are called multi cellular creatures. They have complex structures. They are bigger in size. They are also known as eukaryotes. They have internal organs. DNA and cell nucleus are present separately in each cell of these creatures. Multi cellular organisms have various structures and shapes. Plants, human beings animals are the examples of multi cellular organisms. Unicellular organisms evolved into various multi cellular creatures. Life on earth began in the form of single celled creatures.
A unicellular cell division is binary fission. It has no spindle. Cell division in multi cellular creatures takes place in the process of mitosis, meiosis or both of them. DNA in multi cellular creature’s cell is linear while the DNA in unicellular is circular in the cytoplasm. There is no protein synthesis in unicellular organisms while it exists in multi cellular organisms. There is no chloroplast in the cell of a unicellular organism and therefore no chance of photosynthesis. On the other hand it is the process in multi cellular creatures like plants.