Organisation & Differentiation of Cells (WJEC GCSE Biology: Combined Science)

Differentiation

• Cells with structural features that enable them to perform a specific function are said to be specialised cells
• Cells become specialised by the process of differentiation
  • As an organism develops cells differentiate to form different types of specialised cells
• When a cell differentiates it develops a structure and internal features which enable it to carry out its function

Cell differentiation diagram

An undifferentiated cell can differentiate to produce specialised cells

What are specialised cells?

• A specialised cell is a cell that has a particular structure and internal features
• Structural differences between different types of cells enable them to perform specific functions within an organism
• Specialised cells are more efficient at performing specific functions than non-specialised cells
• Some examples of specialised cells in humans include
  • Nerve cells
  • Muscle cells
  • Sperm cells
  • Red blood cells

• In multicellular organisms specialised cells work together at different levels of organisation to allow organisms to survive

Levels of organisation table

Level	Description
Cells	Basic functional and structural units in a living organism
Tissues	Groups of cells of similar structures working together to perform the same function
Organs	Different tissues working together to perform a specific function
Organ systems	Groups of organs with related functions working together to carry out a particular role

 

Levels of organisation diagram

Cells organised at different levels within multicellular organisms allow all essential body functions to occur efficiently

Levels of organisation examples table

Organ system	Organ	Tissue
Shoot system in plants	Leaf, stem, flower, fruit	Epidermis Spongy mesophyll Phloem
Root system in plants	Root, tuber	Xylem Phloem
Digestive system	Oesophagus, stomach, small and large intestines	Muscle Connective tissue Nerve tissue
Circulatory system	Heart, arteries, veins	Muscle Connective tissue Blood