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Difference Between Unicellular and Multicellular Organisms

Last updated date: 23rd Apr 2024
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In biology, a simple term can be way more complex than its direct meaning. For instance, unicellular and multicellular organisms. At face value, they mean- organisms with one cell and more than one cell. But, is that all there is about characteristics of unicellular and multicellular organisms? No, and that's the reason that there is an explainable difference between unicellular and multicellular organisms. So, are you interested in knowing them? Then all you have to do is- read the article below!

What is Unicellular and Multicellular Organisms?

In the race to learn unicellular and multicellular organisms difference, it's important to understand them individually. Therefore, if you are not already aware of the answer to the question- "what is unicellular and multicellular organisms?" By reading the sub-sections below, you can get the answer! 

Unicellular Organisms

Any living being that is composed of a single cell is put under the term- unicellular organism. To play their role in the environment, they carry out different essential life processes. These processes are- metabolism, reproduction, response to stimuli, etc. All of it, the unicellular organisms manage within a single cell. Amongst some popular unicellular organisms are protozoa, bacteria, and different types of algae.

Multicellular Organisms

When more than a single cell comes together and works as a coordinated unit, forming a living being, they are called multicellular organisms. The cells within multicellular organisms are specialised in performing functions specific to them. Thus, they are capable of maintaining the body's overall functioning. Some of the multicellular organisms that are widely known include- animals, fungi, and plants. The multicellularity gives way to increased complexity and labor division amongst the group of cells in multicellular organisms.

Difference Between Unicellular and Multicellular Organisms

There are different reasons for the difference between unicellular and multicellular organisms. All cannot be mentioned, but, a few of to explain unicellular and multicellular organisms and the characteristics of unicellular and multicellular organisms are given below: 



Unicellular Organisms

Multicellular Organisms



Consist of a single cell

Consist of multiple cells



Small in size

Vary in size, can be microscopic or macroscopic



Simple in structure and function

Complex in structure and function


Cell Specialisation

Lack of specialised cells and tissues

Specialised cells and tissues perform specific functions


Metabolic Requirements

Low metabolic requirements

Higher metabolic requirements



Reproduce asexually through binary fission

Reproduce sexually or asexually


Energy Acquisition

Obtain energy through simple processes like diffusion

Acquire energy through complex feeding mechanisms


Environmental Acquisition

Exhibit rapid adaptation to environmental changes

Adaptation may take longer due to interdependence


Gene Transfer

Exchange genetic material through horizontal gene transfer

Limited gene transfer, primarily vertical inheritance


Response to Environment

Respond to stimuli in a limited manner

Respond to stimuli in a coordinated and diverse manner


Growth and Development

Grow and develop as a single entity

Exhibit organized growth and development



Limited communication between cell

Extensive intercellular communication



Shorter lifespan

Longer lifespan



Simple regulation of internal conditions

Complex regulation of internal conditions


Specialised Structures

Lack of specialised structures like tissues and organs

Possess specialised structures like tissues and organs


Nutrient Distribution

Minimal ecological impact due to small size

Can have a significant ecological impact


Ecological Impact

Minimal ecological impact due to small size

Can have a significant ecological impact



Bacteria, amoeba, yeast, paramecium, etc.

Plants, animals, fungi, algae, etc.

Interesting Features: Unicellular and Multicellular Organisms

All the commonly known features of unicellular and multicellular organisms are discussed above. But, there are some interesting characteristics of unicellular and multicellular organisms. To understand, please read the subsections below:

Unicellular Organisms: Features

Some interesting features of unicellular organisms are mentioned in the points below:

  • The simplest form of life is unicellular organisms as they have only a single cell. 

  • Their adaptability has a variable range and thus, they can easily survive in diverse environments.

  • Because unicellular organisms reproduce quickly and their population growth is very rapid, even minutes at times.

  • Unique structures like feeding and flagella for movement are present in them. 

  • Unicellular organisms like bacteria can form biofilms. This gives them collective protection and cooperation.

Multicellular Organisms: Features

Do you want to learn some interesting features of multicellular organisms? They go through the points below:

  • The complexity level in multicellular organisms is much higher when compared to unicellular organisms.

  • There is a division of labor in multicellular organisms because a group of cells is assigned a particular function specific to them. 

  • Because multiple cells work together in multicellular organisms they can achieve complex bodies and large sizes. 

  • Intricate physiological processes take place in multicellular organisms, courtesy of their ability to develop complex organ systems.


In the end, no matter the difference between unicellular and multicellular organisms, they are both important. But, knowing the differences is important for you and will help give a clear distinction between the two. Thus, help in making your concepts for NEET- strong. Not only that but you can also learn about distinct features in both unicellular and multicellular organisms. So, why wait? Check out the above article, now to explain unicellular and multicellular organisms.

FAQs on Difference Between Unicellular and Multicellular Organisms

1. Are fungi multicellular or unicellular?

There is no one side that fungi take. Therefore, it neither completely has single-celled organisms nor the more complex multicellular organisms. So, the organisms under the kingdom fungi are divided, where few are unicellular and others are multicellular organisms. And these organisms are largely land-living. Thus, they are found in soil or plant matter more than they're found in freshwater or sea.

2. Are plants unicellular or multicellular?

Plants are multicellular organisms that are predominantly photosynthetic eukaryotes, in the kingdom Plantae. They are composed of multiple cells. And they all work together to form tissues, organs, and complex structures (organ systems). One defining characteristic of plants is multicellularity. It allows them to carry out specialised functions. Alongside this, they can also exhibit a wide range of forms and structures.

3. What are 5 examples of multicellular organisms?

Here are shorter descriptions of five multicellular organisms:

1. Humans: Complex multicellular animals with specialized organs and systems.

2. Dogs: Domesticated animals with complex organ systems.

3. Oak Trees: Multicellular plants with roots, stems, leaves, and reproductive structures.

4. Mushrooms: Multicellular fungi with branching filaments and ecological roles in decomposition.

5. Jellyfish: Aquatic animals with specialized structures for feeding and locomotion.