Class 9 Biology | Updated for NCERT 2026-27 | Reading Time: 5 minutes
All living organisms are made of cells, but not all cells are the same. Based on their internal structure, cells are
divided into two major types: prokaryotic and eukaryotic. Understanding the difference
between them is fundamental to biology. Let's explore what makes them unique!
Understanding the Names
The words "prokaryotic" and "eukaryotic" come from Greek:
Pro = before or primitive
Eu = true or well-developed
Karyon = nucleus
So, Prokaryotic means "before nucleus" (primitive, no true nucleus), and Eukaryotic means
"true nucleus" (well-defined nucleus).
Simple Rule to Remember
Prokaryotic = Simple, primitive cells (like bacteria) Eukaryotic = Complex, advanced cells (like your body cells, plant cells)
What is a Prokaryotic Cell?
Prokaryotic cells are the simplest and most ancient type of cells. They were the first forms of life on Earth,
appearing about 3.5 billion years ago.
Key Characteristics:
No well-defined nucleus:
Genetic material (DNA) is not enclosed in a nuclear membrane
DNA lies freely in a region called the nucleoid
The nucleoid is just an area in the cytoplasm where DNA is concentrated
No membrane-bound organelles:
Do not have mitochondria, ER, Golgi apparatus, or lysosomes
All cellular activities happen directly in the cytoplasm
Only ribosomes are present (for protein synthesis)
Small size:
Typically 1–10 micrometres (µm)
Much smaller than eukaryotic cells
Usually unicellular:
Most prokaryotes exist as single-celled organisms
Some can form colonies but each cell remains independent
Cell wall present:
Made of peptidoglycan (different from plant cell walls)
Structure of a prokaryotic cell showing nucleoid region without nuclear membrane
What is a Eukaryotic Cell?
Eukaryotic cells are more complex and advanced cells. They evolved from prokaryotic cells about 2 billion
years ago.
Key Characteristics:
Well-defined nucleus:
Genetic material (DNA) is enclosed within a nuclear membrane
Nucleus has nuclear pores for material exchange
Contains nucleolus and chromatin material
Membrane-bound organelles present:
Mitochondria, ER, Golgi apparatus, lysosomes, vacuoles
Chloroplasts in plant cells
Each organelle has a specific function
Larger size:
Typically 10–100 micrometres (µm)
10 to 100 times larger than prokaryotic cells
Can be unicellular or multicellular:
Unicellular: Amoeba, Paramecium, yeast
Multicellular: Plants, animals, fungi
Division of labour:
Different organelles perform different functions
More efficient than prokaryotic cells
Examples of Eukaryotic Cells:
Plant cells: Onion cells, leaf cells, root cells
Animal cells: Human cheek cells, blood cells, nerve cells
Fungal cells: Yeast, mushroom cells
Protist cells: Amoeba, Paramecium, Euglena
[Figure 2.10b: Eukaryotic Cell Structure]
Insert NCERT Figure 2.10 showing eukaryotic cell with labeled nucleus, mitochondria, ER, Golgi, and other organelles
Structure of a eukaryotic cell showing well-defined nucleus and membrane-bound organelles
Prokaryotic vs Eukaryotic Cells — Comparison Table
Feature
Prokaryotic Cell
Eukaryotic Cell
Meaning of name
Pro = before, primitive
Eu = true, well-developed
Size
Small (1–10 µm)
Large (10–100 µm)
Nucleus
No well-defined nucleus
Well-defined nucleus with nuclear membrane
Nuclear membrane
Absent
Present
Genetic material
DNA in nucleoid region (not enclosed)
DNA enclosed within nucleus
Chromosomes
Single, circular chromosome
Multiple, linear chromosomes
Nucleolus
Absent
Present
Membrane-bound organelles
Absent (no mitochondria, ER, Golgi, lysosomes)
Present (mitochondria, ER, Golgi, lysosomes, etc.)
Ribosomes
Present (smaller, 70S type)
Present (larger, 80S type)
Cell wall
Present (made of peptidoglycan)
Present in plants (cellulose); absent in animals
Cell organisation
Usually unicellular
Unicellular or multicellular
Division of labour
No division of labour (all activities in cytoplasm)
Division of labour (different organelles for different functions)
Examples
Bacteria, Cyanobacteria
Plants, Animals, Fungi, Protists
Important Note
Table 2.2 from NCERT: The comparison table above is based on NCERT Table 2.2. Make sure to refer to
the textbook for the exact table format and additional details.
Key Terms to Remember
Prokaryotic Cell
Simple cell without a well-defined nucleus or membrane-bound organelles; genetic material in nucleoid region.
Eukaryotic Cell
Complex cell with a well-defined nucleus and membrane-bound organelles.
Nucleoid
Region in prokaryotic cells where genetic material (DNA) is located; not enclosed by a membrane.
Membrane-bound Organelles
Organelles enclosed by membranes (mitochondria, ER, Golgi, lysosomes); present only in eukaryotic cells.
Nuclear Membrane
Double-layered membrane enclosing the nucleus in eukaryotic cells; has nuclear pores.
Peptidoglycan
Material that forms the cell wall in prokaryotic cells (bacteria).
5 Important Questions with Answers
Q1. What is the main difference between prokaryotic and eukaryotic cells?
The main difference is the presence or absence of a well-defined nucleus:
Prokaryotic cells: Do NOT have a well-defined nucleus. Their genetic material (DNA) lies freely
in the cytoplasm in a region called the nucleoid. They also lack membrane-bound organelles.
Eukaryotic cells: HAVE a well-defined nucleus with a nuclear membrane that encloses the DNA.
They also have membrane-bound organelles like mitochondria, ER, and Golgi apparatus.
Simple way to remember: Prokaryotic = No nucleus; Eukaryotic = Has nucleus
Q2. Give two examples each of prokaryotic and eukaryotic cells.
Additional examples: Fungi (yeast, mushrooms) and Protists (Amoeba, Paramecium) are also eukaryotic.
Q3. What is a nucleoid? How is it different from a nucleus?
Nucleoid is a region in prokaryotic cells where genetic material (DNA) is located.
Difference between Nucleoid and Nucleus:
Nucleoid
Nucleus
Found in prokaryotic cells
Found in eukaryotic cells
NOT enclosed by a membrane
Enclosed by a nuclear membrane
Just a region in cytoplasm
Well-defined organelle
DNA is not organised into chromosomes
DNA is organised into chromosomes
No nucleolus
Has nucleolus
In simple terms: Nucleoid is an open area with DNA floating freely, while nucleus is a closed
compartment with DNA safely enclosed inside.
Q4. Do prokaryotic cells have any organelles?
Prokaryotic cells do NOT have membrane-bound organelles like mitochondria, ER, Golgi apparatus,
or lysosomes.
However, they DO have ribosomes — small structures that make proteins. Ribosomes are NOT enclosed
by membranes, so they are not considered membrane-bound organelles.
What prokaryotic cells have:
Ribosomes (for protein synthesis)
Cell wall (for protection and shape)
Plasma membrane (controls entry and exit)
Cytoplasm (where all activities happen)
Nucleoid (region with DNA)
Q5. Why are eukaryotic cells more advanced than prokaryotic cells?
Eukaryotic cells are considered more advanced because they have:
Division of labour: Different organelles perform different functions, making the cell more efficient.
For example, mitochondria make energy, ER transports materials, Golgi packages products — all working together smoothly.
Protected genetic material: DNA is safely enclosed in the nucleus, protecting it from damage.
Larger size: Can be 10-100 times larger than prokaryotic cells, allowing more complex functions.
Ability to form multicellular organisms: Eukaryotic cells can specialise and work together to
form tissues, organs, and organ systems, creating complex life forms like humans, trees, and animals.
More organised: Compartmentalisation (separate organelles) allows different processes to happen
simultaneously without interfering with each other.
Prokaryotic cells are simpler — all activities happen in the cytoplasm without specialised compartments. This limits
their complexity and efficiency.
