differences between prokaryotic and eukaryotic cells

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.

When comparing prokaryotic and eukaryotic cells, think about them as two different kinds of living quarters with some fundamental differences in how they're organised.

1. Size and Complexity:

• Prokaryotic cells are like a simple studio apartment. They are small and have just the basics you need to live. These are the types of cells that bacteria have.
• Eukaryotic cells are more like a large house with several rooms, each serving a specific purpose. These cells are bigger and much more complex. Humans, plants, fungi, and animals all have eukaryotic cells.

1. Nucleus:

• Prokaryotic cells don’t have a nucleus. Their DNA, which is like the instruction manual for building and maintaining the cell, is just floating around in the middle of the cell, usually in a single, circular strand.
• Eukaryotic cells have a nucleus, which acts like a special room where the DNA is kept safe and organised. This nucleus is surrounded by a membrane, keeping the DNA separated from other cell parts.

1. Organelles:

• Prokaryotic cells are pretty basic and don't have many distinct structures called organelles. They do their business directly in the cell fluid.
• Eukaryotic cells have lots of different organelles, like mitochondria (power plants), lysosomes (recycling centres), and Golgi apparatus (shipping centres), each enclosed by membranes and specialised for different cell functions.

1. Cell Division:

• Prokaryotic cells reproduce by a simple process called binary fission, where the cell just splits into two after duplicating its DNA.
• Eukaryotic cells usually use a process called mitosis for cell division, which is more complicated but ensures that each new cell gets exactly the right amount of DNA.

1. Complexity of Tasks:

• Prokaryotic cells are generally single-celled organisms, meaning each cell operates independently.
• Eukaryotic cells often work together forming multicellular organisms, like us! This teamwork allows for specialised cells that perform specific functions, making more complex life forms possible.

So, in a nutshell, prokaryotic cells are like simple, one-room homes with minimal furnishings, while eukaryotic cells are like big houses with special rooms for specific tasks, making them suitable for more complex and large organisms!

Following are the some of the differences between Prokaryotic and Eukaryotic cells.

1. Nucleus: Prokaryotic cells lack a distinct nucleus, while eukaryotic cells have a membrane-bound nucleus that houses their genetic material (DNA).

2. Size and Complexity: Prokaryotic cells are generally smaller and simpler in structure compared to eukaryotic cells, which are typically larger and more complex.

3. Genetic Material: In prokaryotic cells, the genetic material is usually a single circular DNA molecule located in the cytoplasm, whereas eukaryotic cells have multiple linear DNA molecules enclosed within the nucleus.

4. Membrane-bound Organelles: Eukaryotic cells contain membrane-bound organelles such as mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes, which perform specific functions. Prokaryotic cells lack these membrane-bound organelles.

5. Cell Division: Prokaryotic cells reproduce through binary fission, a process where the cell divides into two identical daughter cells. Eukaryotic cells undergo mitosis or meiosis, which involves complex stages of nuclear division and cytoplasmic division.

6. Ribosomes: Both types of cells have ribosomes, but in prokaryotic cells, ribosomes are smaller and free-floating in the cytoplasm, while in eukaryotic cells, they are larger and can be found both free-floating and attached to the endoplasmic reticulum.

7. Cell Wall: Many prokaryotic cells have a cell wall outside the plasma membrane, providing structural support and protection. Some eukaryotic cells, such as plant cells and fungi, also have a cell wall, but it is chemically different from that of prokaryotes.

The primary difference between prokaryotic and eukaryotic cells is that a nucleus and other membrane-bound organelles are only present in eukaryotic cells. Prokaryotes are always unicellular, while eukaryotes are often multi-celled organisms. Additionally, eukaryotic cells are more than 100 to 10,000 times larger than prokaryotic cells and are much more complex.

The DNA in eukaryotes is stored within the nucleus, while DNA is stored in the cytoplasm of prokaryotes. Additionally, DNA in eukaryotic cells is stored in double-stranded chromosomes that are condensed by histones. In contrast, prokaryotic cells have one primary circular chromosome and various plasmids, which are small rings of DNA. The DNA of eukaryotic cells has proportionally less coding DNA and high amount of non-coding DNA compared to prokaryotic cells.