All organisms can be divided into two groups – eukaryotes or prokaryotes. The cellular structure determines which group an organism belongs to. In this article, we will explore the difference between prokaryotes and eukaryotes.
The main difference between prokaryotic and eukaryotic cells lies in their structure. Prokaryotic cells don't have a nucleus and have free-floating genetic material while eukaryotic cells have a distinct nucleus containing the cell's genetic material. Find all the major differences in the table below.
| Feature | Prokaryotic Cells | Eukaryotic Cells |
| Nucleus | No true nucleus; DNA is in the nucleoid region | True nucleus enclosed by a nuclear membrane |
| Cell Size | Generally small (1-10 µm) | Larger (10-100 µm) |
| DNA Structure | Circular DNA | Linear DNA |
| Membrane-bound Organelles | Absent | Present (e.g., mitochondria, ER, Golgi apparatus) |
| Ribosomes | Small (70S) | Larger (80S) |
| Cell Division | Binary fission | Mitosis and meiosis |
| Plasma Membrane | Lacks cholesterol | Contains cholesterol |
| Cell Wall | Often present (e.g., peptidoglycan in bacteria) | In plants (cellulose), fungi (chitin), absent in animals |
| Flagella | Simple, made of flagellin | Complex, made of tubulin |
| Cytoplasm | Simple, no cytoskeleton | Complex, with a cytoskeleton |
| Reproduction | Asexual (binary fission) | Sexual or asexual |
| Respiratory Enzymes | Located in the cell membrane | Located in mitochondria |
| Endocytosis | Absent | Present (engulfing material into the cell) |
| Number of Chromosomes | Usually one (haploid) | More than one (diploid or polyploid) |
| Genetic Exchange | Horizontal gene transfer (e.g., conjugation) | Vertical gene transfer (inheritance) |
| Examples | Archaea, Bacteria | Plants, animals, fungi |
The prokaryotic and eukaryotic cells have four common features –
| Type | Examples |
| Prokaryotic Cells |
|
| Eukaryotic Cells |
|
Prokaryotic (pro- = before; -karyon- = nucleus) cells are single-celled organisms characterised by the absence of a nucleus and membrane-bound cellular organelles. They are the simplest and oldest forms of life on Earth discovered over 3.5 billion years ago play a crucial role in the biosphere.
All prokaryotic cells have four common components –
The other commonly found features are –
Bacteria: These are tiny, single-celled organisms found everywhere, from dirt to our bodies. They come in various shapes and can live in many different conditions. Some help break down materials, while others can cause diseases.
Archaea: These are also single-celled but are quite different from bacteria. They often live in extreme places like hot springs or salty environments. Archaea play important roles in natural processes like recycling nutrients.
Metabolism: Prokaryotic cells use various metabolic processes, including aerobic respiration (with oxygen), anaerobic respiration (without oxygen), and fermentation. They adapt to different environments, thriving in extreme conditions.
Reproduction: They reproduce by binary fission, creating two identical cells, and exchange genes through horizontal transfer, promoting genetic diversity.
Environmental Impact: Prokaryotes play key roles in nutrient cycling, such as nitrogen fixation and decomposition, crucial for ecosystem health.
Human Relevance: They contribute beneficial bacteria for digestion and can be pathogens. In biotechnology, they are used for making medicines, bioremediation, and industrial processes.
Coli: Common gut bacteria
Streptococcus: Causes infections like strep throat.
Bacillus anthracis: Causes anthrax.
Methanogens: Produce methane in extreme environments.
Thermophiles: Thrive in hot springs and vents.
Eukaryotes (eu- = true; -karyon- = nucleus). are cells that possess a true nucleus and membrane-bound organelles. They can be unicellular or multicellular. Found in plants, animals, fungi, and protists, it features a defined nucleus, various organelles like mitochondria and chloroplasts, and a cell membrane that regulates the entry and exit of substances.
A more complex eukaryotic cell has membrane-bound compartments or sacs called organelles. Each of these membrane-bound structures performs specific cellular functions. Organelle means little organ and just like the organs of the body have special functions, organelle have special functions within the cell.
The primary parts of eukaryotic cell are –
Other common organelles found in many, but not all, eukaryotes include the Golgi apparatus, chloroplasts and lysosomes.
Animal Cells: These cells lack a cell wall and chloroplasts but have a flexible membrane. They include various types, like nerve and muscle cells, each with specific functions.
Plant Cells: Plant cells have a rigid cell wall and chloroplasts for photosynthesis. They also have large vacuoles for storage and maintaining structure.
Fungal Cells: Found in fungi, these cells have a cell wall made of chitin. They are involved in decomposing organic matter and can have complex structures.
Protists: A diverse group of single-celled eukaryotes, protists include algae and protozoa. They live in various environments and have features like cilia or flagella for movement.
Metabolism: Cells use cellular respiration for energy and, in plants, photosynthesis to make food.
Reproduction: Mitosis helps with growth and repair, while meiosis ensures genetic diversity in sexual reproduction.
Cell Communication: Cells communicate through signalling pathways, coordinating their activities and responses.
Animal Cells: Nerve cells, muscle cells, and skin cells.
Plant Cells: Leaf cells, root cells, and stem cells.
Fungal Cells: Yeast cells and mold cells.
Protist Cells: Algae cells, such as those in pond water, and protozoa, like amoebas.
Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have a defined nucleus and various organelles.
Prokaryotic cells reproduce asexually through binary fission, where the cell divides into two identical cells.
Examples include E. coli, Streptococcus, Bacillus anthracis, methanogens, and thermophiles.
Key organelles include the nucleus (genetic material storage), mitochondria (energy production), endoplasmic reticulum (protein and lipid synthesis), and Golgi apparatus (protein modification and packaging).
Eukaryotic cells reproduce through mitosis (for growth and repair) and meiosis (for sexual reproduction and genetic diversity).
Major types include animal cells, plant cells, fungal cells, and protist cells.
Ribosomes are responsible for protein synthesis in both prokaryotic and eukaryotic cells, though their structure may differ slightly.
Prokaryotic cells have DNA located in the nucleoid region without a membrane, while eukaryotic cells have DNA enclosed in a nucleus.
Prokaryotic cells can perform specialised functions such as nitrogen fixation and biodegradation, but they lack the compartmentalisation seen in eukaryotic cells.
Prokaryotic cells play roles in nutrient cycling and decomposition, while eukaryotic cells contribute to photosynthesis, food webs, and complex interactions within ecosystems.
Brochure
© Knowledgeum Academy
