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

Unicellular and Multicellular meaning.jpg

 

Difference between multicellular and unicellular organisms

 

Unicellular

Multicellular

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

Unicellular Organisms and Multicellular Organisms - Teachoo.png

 

 

 

Basic Structure of Multicellular Organisms

Cells

Multicellular organisms are made of trillions of cells

 

Tissues

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

Example

Muscle tissue,Nervous tissue etc

 

Organs

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



Organisms

Different Organs combine to form organisms

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

 

Note

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

Multicellular Organisms animal and Plants - Teachoo.jpg

Functions performed by organs - Teachoo.jpg

 

Questions

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 Functions

Transcript

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 - Expert in Practical Accounts, Taxation and Efiling
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 9 years and a teacher from the past 16 years. He teaches Spoken English, Written English, Grammar and Vocabulary at Englishtan.