Difference between Prokaryotes and Eukaryotes

Key difference: The main difference between prokaryotes and eukaryotes is based on their different size and cell structure.

All living organisms can be divided into two groups based on the fundamental structure of their cells. Accordingly, they can be classified as the prokaryotes and eukaryotes. This article differentiates between the two classes of organisms.

Prokaryotes are organisms made up of cells that lack a cell nucleus or any membrane-encased organelles. This means that they have no nucleus. Also, the genetic material i.e. DNA, in prokaryotes is not bound within a nucleus. The term prokaryote is derived from the Greek word “prokaryote”, which means before nuclei.

Most prokaryotes are made up of just a single cell and are called as unicellular organism. Here, reproduction takes place through binary fission. Also, there are a few prokaryotes which are made of a collection of cells and are called as multi-cellular organisms. The prokaryotes are divided into two groups, they are:

Bacteria
Archaea

Eukaryotes

Eukaryotes are organisms made up of cells that possess a membrane-bound nucleus as well as membrane-bound organelles. The term eukaryote is derived from the Greek word “œeukaryoteâ”, which means true or good nuclei. This cell includes all life kingdoms except ‘monera’. Here, the division of cells takes place in two ways:

Mitosis - one cell divides to produce two genetically identical cells
Meiosis - where sexual reproduction is required.

These organisms hold the genetic material in their cells. The genetic material in eukaryotes is contained within a nucleus in a cell. The DNA of these organisms is structured and is organized into chromosomes. Eukaryotic organisms may be multi-cellular or single-celled organisms. All animals are considered as eukaryotes. They can be further classified as:

Plant cells
Animal cells

Comparison between Prokaryotes and Eukaryotes:

	Prokaryotes	Eukaryotes
Definition	These are organisms made up of cells that lack a cell nucleus or any membrane-encased organelles.	These organisms made up of cells that possess a membrane-bound nucleus as well as membrane-bound organelles.
Nucleus	It has no nucleus.	It has a true nucleus, bounded by double membrane.
DNA arrangement	It has a circular loop.	It is linear.
Size	Small cells ( < 5 µm)	Large cells ( < 10 µm)
Cell	Always unicellular	Mostly multi-cellular
Cell wall	Usually present; chemically complex in nature	When present, chemically simple in nature
Protein	It does not contain protein in its DNA.	It contains proteins in the DNA to form chromatin.
Ribosome	It contains small ribosomes.	It contains large ribosomes.
Cytoplasm	No cytoskeleton	Always have cytoskeleton
Cell division	Cell division is by binary fission	Cell division is by mitosis
Reproduction	Reproduction is always asexual	Reproduction is asexual or sexual
Metabolic pathways	Huge variety of metabolic pathways	Common metabolic pathways
Flagella	Consist of two protein building blocks	It is complex in nature and consist of multiple microtubules
Multi-cellular forms	Rare	Common with extensive tissue formation
Mesosomes	They perform functions of golgi-bodies and mitochondria, and also help in separation of chromosomes.	Not present
Plasma membrane	No carbohydrates and lacks sterols	Sterols and carbohydrates, both are present
Glycocalyx	Present as a capsule or slime layer	Present in some cells which lack a cell wall
Example	Bacteria and Archaea	Animal cells and plant cells