There are two types of cells: Eukaryotes and Prokaryotes.
Eukaryotic cells are those that have organelles with membranes and a nucleus.
Because they are more complex, they are also considerably larger than prokaryotes.
There are lots of different organisms that have eukaryotic cells including animals, plants, protists, and even fungi.
Eukaryotic cells have organelles such as endoplasmic reticulum, mitochondria, and a nucleus.
The requirements of organelles make them larger than prokaryotes. The average size of a eukaryote is from 10-100 micrometers and the average size of a prokaryote is around 1-3 micrometers.
While most eukaryotes are part of organisms that are multi-cellular, there are some exceptions to this in single-celled protists which have eukaryotic cells.
The organelles in eukaryotes are important because they assist in carrying out the complex and detailed processes required by the cell, and each organelle is assigned a specific function.
An example of this would be in looking at the mitochondria organelle whose job is to make energy for the cell to use.
Another difference in the two types of cells is in the DNA. Prokaryotes such as bacteria have a single circular loop shape for their DNA.
Eukaryotes have DNA that is housed and protected in the nucleus organelle with arranged chromosomes.
Scientists that study the cells believe that eukaryotic cells evolved between 1.7-1.9 billion years ago.
They think they began without organelles or a nucleus and were eukaryotic cells. The theory is that some of these cells consumed or “ate” the other cells and as they learned to survive together, the cells inside eventually became organelles.
This development theory is called the endosymbiotic hypothesis. “Symbiotic” means a survival that lives with and depends on each other.
As time passed, the evolution of the original eukaryotes allowed them to move into smaller groups and become plant, animal, fungi, and protest cells.
They are all different and have totally unique features, but all are eukaryotic cells.
The complex nature of eukaryotic cells include the fact that they have the ability to accomplish many tasks.
This is due to an organized nucleus with a nuclear envelope that is kind of the “brain” of the cell.
They have DNA that is protected as well as the many organelles that can work together to be a self-sufficient organism.
There is a lot going on in the eukaryotic cell. Having organized DNA and organelles gives them to power to create their own parts.
An example of this is the tail-like structure that they have called the “flagellum”. This gives them movement.
They also create small hairs called “cilia” that allow the cell to scoot around through fluids. Other eukaryotic cells such as those called “nematocysts” have small harpoons that they use to catch prey.
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