differences between prokaryotic and eukaryotic cells

Prokaryotic cells(e.g. in a bacterium) are cells without a true nucleus. Their DNA is floating freely in the cytoplasm. They do not have any membrane bound organelles, only ribosomes. Because of these they tend to be much smaller than eukaryotic cells.

Eukaryotic cells(e.g. human cells) are much larger than prokaryotic cells. This is because their DNA is enclosed in a nucleus and they have membrane bound organelles(e.g. mitochondria). Their ribosomes are also bigger than those of prokaryotic cells.

The main difference is that eukaryotic cells have a distinct nucleus which tells the cell what to do but prokaryotic cells don't have one, though they have free floating genetic material in the cytoplasm of the cell.

prokaryotic cells lack membrane bound organelles and a well defined nucleus, reproduce mainly through binary fission while eukaryotic cells have a well defined nucleus and membrane bound organelles, reproduce through mitosis.

Prokaryotic cells are generally simpler in structure to eukaryotes, the key difference being they lack membrane-bound organelles and a distinct nucleus, unlike eukaryotic cells. Some of these organelles include:

1. Nucleus: A membrane-bound organelle that houses the cell's genetic material (DNA) responsible for controlling cellular activities
2. Mitochondria: responsible for generating energy in the form of ATP
3. Endoplasmic reticulum (ER): A network of membranes involved in protein synthesis, lipid metabolism, and calcium storage.
4. Golgi apparatus: A stack of membrane-bound vesicles that processes and packages proteins and lipids for transport within or outside the cell

Interestingly, the endosymbiotic theory suggests that certain organelles found in eukaryotic cells, such as mitochondria, were once free-living prokaryotic organisms that were engulfed and formed a symbiotic relationship with the host cell, ultimately becoming integrated as organelles and forming the early eukaryotic cells.

Prokaryotic cells have no nucleus, mitochondria, chloroplasts or any membrane-bound organelles, unlike eukaryotic cells. Prokaryotic cells have plasmids and a loop of genetic material instead of chromosomes and some have a slime capsule.

Prokaryotic cells, found in bacteria and archaea, are generally smaller and simpler. They lack a true nucleus and other membrane-bound organelles. Their DNA is usually a single circular molecule located in the nucleoid region.

In contrast, eukaryotic cells, present in plants, animals, fungi, and protists, are larger and more complex. They have a distinct nucleus enclosed by a nuclear membrane. Eukaryotic cells contain membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus, which perform specialized functions. Additionally, their DNA is organized into multiple linear chromosomes within the nucleus.

There are a couple of ways that Prokaryotic and Eukaryotic cells differ that are on any GCSE specification, I have listed a few of these below:

Structure:

• Prokaryotic cells have a much simpler structure and do not have a nucleus. Their genetic material is found in the cytoplasm.

• Eukaryotic cells are much more complex and do have nucleus where we know stores the genetic material of the cell.

Size:

• Prokaryotic cells tend to be much smaller in size, usually ranging from 0.1 to 5 micrometers.

• Eukaryotic cells: Larger in size, ranging from 10 to 100 micrometers.

Membrane-bound Organelles:

• Prokaryotic cells do not contain membrane-bound organelles. A prime example of an organelle that prokaryotic cells do not contain is mitochondria.

• Eukaryotic cells do contain membrane-bound organelles such as mitochondria and chloroplasts (in plant cells).

Cell Division:

• Prokaryotic cells reproduce through a process called binary fission where the cell splits into two identical daughter cells.

• Eukaryotic cells: Undergo mitosis or meiosis during cell division, both of which involve different complex steps.

Prokaryotic cells are like tiny, simple organisms found in bacteria and archaea, lacking a central nucleus or special compartments within them. They reproduce by splitting in two and are smaller compared to eukaryotic cells. Eukaryotic cells, on the other hand, are more complex and found in plants, animals, and other living things. They have a nucleus and various compartments with specific jobs. When they divide, they go through more complicated processes. Eukaryotic cells are bigger, have more parts like mitochondria and endoplasmic reticulum, and contain larger ribosomes compared to prokaryotic cells. These differences help each type of cell perform different functions.

So the main differences are as follows:

-Prokaryotes - Simple unicellular organisms; DONOT have membrane bound organelles within their cell hence different organelles lie within the cytoplasm without any membrane or barrier.

-Eukaryotes - Complex, multicellular organisms; HAVE membrane bound organelles within their cell i.e nucleus.

Now lets think of different features of any typical cell and lets see how those features are different in prokaryotes and eukaryotes:

Nucleus:

-Prokaryotic cells lack a true nucleus. Their genetic material (DNA) is not enclosed in a membrane; it's typically found in a single, circular chromosome located in an area called the nucleoid.

-Eukaryotic cells have a well-defined nucleus, where the DNA is stored. The nucleus is surrounded by a nuclear envelope, a double membrane that separates it from the cytoplasm.

Cell Size:

-Prokaryotic cells are generally smaller in size, usually ranging from 0.1 to 5 micrometers.

-Eukaryotic cells are larger, typically between 10 and 100 micrometers.

Cell Complexity:

-Prokaryotic cells are simpler in structure, with no true organelles (membrane-bound structures) other than ribosomes.

-Eukaryotic cells are more complex, containing multiple organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus, which perform specific functions.

Cell Wall:

-Prokaryotic cells often have a cell wall

-Eukaryotic cells may or may not have a cell wall. If present, the cell wall is made of different substances, like cellulose in plants or chitin in fungi. Animal cells do not have a cell wall.

Ribosomes:

Both cell types have ribosomes, but they differ in size and structure. Prokaryotic ribosomes (70S) are smaller than eukaryotic ribosomes (80S).

Reproduction:

-Prokaryotic cells reproduce asexually through a process called binary fission, where the cell divides into two identical cells.

-Eukaryotic cells can reproduce both asexually (through mitosis) and sexually (through meiosis).

Genetic Material:

-Prokaryotic cells typically have a single, circular chromosome.

-Eukaryotic cells have multiple, linear chromosomes contained within the nucleus.

Nucleus: Prokaryotic cells have no true nucleus, the DNA floats freely in the cytoplasm in a region called the nucleoid. Whereas Eukaryotic cells have a membrane-bound nucleus that separates the genetic material (DNA) from the cytoplasm.

Organelles: Prokaryotic cells lack membrane-bound organelles. Whereas Eukaryotic cells have many membrane-bound organelles that perform specific functions, like mitochondria (energy production), endoplasmic reticulum (protein synthesis and transport), Golgi apparatus (packaging and secretion), and lysosomes (waste disposal).

Size: Prokaryotic cells are generally much smaller and simpler than eukaryotic cells.

Other Differences:

DNA Structure: Prokaryotic DNA is usually circular, while eukaryotic DNA is linear.

Organisms: Prokaryotes are unicellular (single-celled) organisms like bacteria and archaea. Eukaryotes can be unicellular (amoeba) or multicellular (plants, animals, fungi).

Examples of Eukaryotic cells are Animal cells and Plant cells. An example of Prokaryotic cells are Bacterial cells.

• Eukaryotic cells contain their genetic material- DNA, enclosed in a nucleus. Whereas in Prokaryotic cells, the genetic material- DNA, is not enclosed in a nucleus.
• In Prokaryotic cells genetic material is found in a single loop of DNA and small rings of DNA known as Plasmids.
• Prokaryotic cells have a singular chromosome located in the Nucleoid, whereas Eukaryotic cells have multiple linear chromosomes located in the Nucleus.
• Prokaryotic cells measure around 1- 10 μm, whilst Eukaryotic cells are 5 - 100μm, therefore Prokaryotic cells are significantly smaller than Eukaryotic cells.
• In Prokaryotic cells membrane bound organelles are absent whilst they are present in Eukaryotic cells. Examples include; Mitochondria, Golgi Apparatus & Endoplasmic Reticulum.

Eukaryotes are plants and animals whereas,Prokayotes are bacteria and fungi

Hi Elizabeth,

for GCSE Biology, you need to know that a eukaryotic cell has membrane-bound organelles, which are the nucleus, the mitochondria and (in cells that photosynthesise) the chloroplasts. Prokaryotic cells do not have any membrane- bound organelles. A major difference you should focus on is that eukaryotic cells have a nucleus whereas prokaryotic cells don’t. This is important as it means that prokaryotic cells need to store their DNA in a different way. Most of their DNA is stored in a circular chromosome that floats in the cytoplasm. They also have plasmids which store extra DNA.

For your exams, you are often asked to fill in a comparison table of the organelles found in eukaryotic and prokaryotic cells. You may be asked more specifically about different types of eukaryotic cells: plants, animals and fungi. Make sure you know the different features of each and can give an example e.g yeast is an example of a single called fungus.

prokaryotic cells have primitive nucleus while eukaryotic cells have well developed nucleus.

Prokaryotic cells do not contain a nucleus.