Some organisms have billions and trillions of cells in a living organism Like Human Beings, Dog, Cat

They are called multi cellular organism


However, there are some organisms which have only one cell Like Bacteria

They are called unicellular or single celled organisms



Difference between multicellular and unicellular organisms




They have only one cell

All the functions are performed by a single cell

Example - Amoeba and Paramecium

They have multiple cells

Different cells perform different functions

Example Human,Animal and Plants





Basic Structure of Multicellular Organisms


Multicellular organisms are made of trillions of cells



A group of cells work together to perform same function which is called tissues


Muscle tissue,Nervous tissue etc



Group of tissues combine to form organs

Example - Lungs,Brain ,Kidney are organs


These organs perform different functions(called organ systems)

Example - Stomach ,intestine etc perform digestive function


Different Organs combine to form organisms

Example - Human Beings, Dog, Cats, Plants are organisms



In Unicellular organisms, all these functions are performed by single cell





NCERT Question 1 (a) - Indicate whether the following statements are True (T) or False (F).

Unicellular organisms have one-celled body. (T/F)

View Answer


  1. Class 8
  2. Chapter 8 Class 8 - Cell - Structure and Function


Uni - cellular One Cell Multi - cellular Many Cell Functions performed by Organs Organs in Human Heart helps in bringing blood to various tissues Lungs help in exchange of oxygen Organs in Plants Roots help to absorb water and minerals Leaves are responsible for synthesis of food

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo