Cell differentiation and specialisation

Cell differentiation is the process by which cells become specialised to perform specific functions. This process is essential for the development and survival of multicellular organisms, such as plants and animals.

In Animals:

• Most animal cells differentiate at an early stage of development to form the various tissues and organs necessary for the body to function.

• In mature animals, cell division is mainly limited to repair and replacement, as most animal cells lose the ability to differentiate after this initial stage.

In Plants:

• Unlike animal cells, many plant cells retain the ability to differentiate throughout their life. This ongoing ability allows plants to grow continuously, adapt to their environment, and form new tissues as needed.

As cells differentiate, they develop specific structures and features that enable them to carry out their specialised functions effectively. This process results in specialised cells, each adapted to perform a particular role in the organism.

Each specialised cell has unique structures that relate directly to its function within a tissue, organ, organ system, or the entire organism. Understanding how cell structure supports function is key to understanding how complex organisms operate efficiently.

Specialised animal cells

• Sperm Cells: Specialised to deliver DNA to the egg cell. They have a tail for swimming, a streamlined shape for efficient movement, and numerous mitochondria to provide the energy needed for swimming.

• Nerve Cells: Specialised to carry electrical impulses throughout the body. They are long, allowing them to cover long distances, and have branched ends to connect with multiple other cells.

• Muscle Cells: Specialised for contraction and relaxation to facilitate movement. They are long and contain many mitochondria to supply the energy required for contraction.

Specialised plant cells

• Xylem Cells: Specialised to transport water from the roots up through the plant. They are hollow, dead tubes, allowing water to move with minimal resistance.

• Phloem Cells: Specialised to transport food (glucose) from the leaves to other parts of the plant. Phloem cells form living tubes, allowing substances to be moved by active transport when necessary.

• Root Hair Cells: Specialised to absorb water and minerals from the soil. They have long, hair-like extensions that increase surface area for more efficient absorption.