Importance of Cell Differentiation (Edexcel IGCSE Biology)

• The structural differences between different types of cells enable them to perform specific functions within the organism
• Cell differentiation is an important process by which a cell changes to become specialised
  • Cell differentiation is how cells develop the structure and characteristics needed to be able to carry out their functions
  • Specialised cells are those that have developed certain characteristics that allow them to perform particular functions. These differences are controlled by genes in the nucleus
• As an organism develops, cells differentiate to form different types of cells
• When a cell differentiates, it develops a structure and composition of subcellular structures which enables it to carry out a certain function
  • E.g. to form a nerve cell the cytoplasm and cell membrane of an undifferentiated cell must elongate to form connections over large distances

Diagram showing the possible differentiation of a human cell into two different cell types

Differentiation and development

• As a multicellular organism develops, its cells differentiate to form specialised cells
  • In an animal, most cells differentiate at an early stage of development
  • As a result, animal cells lose their ability to differentiate early in the life of the organism
• Specific cells in various locations throughout the body of an animal retain the ability to differentiate throughout the life of the animal
  • These undifferentiated cells are called adult stem cells and they are mainly involved in replacing and repairing cells (such as blood or skin cells)
• Plants differ from animals in that many types of plant cells retain the ability to fully differentiate throughout the life of a plant, not just in the early stages of development

Examples of specialised cells

Ciliated cell

• Ciliated cells move mucus in the trachea and bronchi
• They have hair-like extensions called cilia, which beat to transport mucus and trapped particles toward the throat

Ciliated epithelial cells

Nerve cell

• Nerve cells conduct impulses and are long, allowing communication between different parts of the body and the central nervous system
• Their axons are covered in a fatty sheath that insulates and speeds up nerve transmission

A nerve cell

Red blood cell

• Red blood cells transport oxygen efficiently due to their biconcave shape, increasing surface area for oxygen diffusion
• They contain haemoglobin and lack a nucleus, maximizing space for oxygen transport

Red blood cells

Root hair cell

• Root hair cells absorb water and mineral ions from the soil
• Their long extensions increase surface area for maximum absorption, and their thin walls help water move quickly through them

Root hair cell

Palisade mesophyll cell

• Palisade mesophyll cells perform photosynthesis and are column-shaped to maximize light absorption
• They contain numerous chloroplasts and are tightly packed beneath the upper epidermis of the leaf to optimize photosynthesis

Palisade mesophyll cell