1.1.3 Cell Specialisation

Cell specialisation is where cells acquire specific structures and functions to perform specialised tasks within a tissue, organ, organ system, or the entire organism.

Specialised Cells in Animals

Sperm Cells:

• Structure: Sperm cells are specialised reproductive cells found in animals. They are streamlined with a long, whip-like tail called a flagellum, which enables them to swim towards the egg. Sperm cells also have a compact, streamlined head that contains genetic material (DNA) to be delivered to the egg.
• Function: The structure of sperm cells is optimised for efficient swimming and fertilisation of the egg during sexual reproduction.

Nerve Cells (Neurons):

• Structure: Nerve cells are specialised cells that transmit electrical impulses in animals’ nervous systems. They have long extensions called axons, which enable the transmission of signals over long distances. Neurons also possess dendrites, which receive signals from other neurons and facilitate communication.
• Function: Nerve cells play a critical role in transmitting information and coordinating communication within the nervous system, allowing for sensory perception, motor control, and overall body coordination.

Muscle Cells:

• Structure: Muscle cells, or muscle fibres, are specialised cells responsible for movement in animals. They are long and contain contractile proteins that allow them to generate force and produce movement. Muscle cells are often organised into bundles or layers to form muscles.
• Function: Muscle cells contract and relax to generate the force needed for body movements, including voluntary movements (skeletal muscles) and involuntary movements (smooth muscles and cardiac muscles).

Specialised Cells in Plants

Root Hair Cells:

• Structure: Root hair cells are specialised cells found in the roots of plants. They have long, slender projections called root hairs that increase the surface area of the root for absorption of water and minerals.
• Function: Root hair cells maximise the absorption of water and nutrients from the soil, facilitating their transportation to other parts of the plant.

Xylem Cells:

• Structure: Xylem cells are specialised plant cells involved in the transport of water and minerals. They have hollow, tube-like structures formed by elongated cells called vessels or tracheids. Xylem cells are reinforced with lignin, providing strength and support.
• Function: Xylem cells facilitate the upward movement of water and dissolved nutrients from the roots to the rest of the plant, ensuring proper hydration and nutrient distribution.

Phloem Cells:

• Structure: Phloem cells are specialised plant cells responsible for the transportation of sugars, organic compounds, and other substances. They consist of living cells, including sieve tube elements and companion cells, interconnected by pores called sieve plates.
• Function: Phloem cells transport sugars produced during photosynthesis (assimilates) from the leaves to other parts of the plant, supporting growth, metabolism, and storage.

Conclusion

Specialised cells demonstrate the remarkable adaptability of organisms to perform specific functions within tissues, organs, organ systems, and the entire organism. Sperm cells, nerve cells, and muscle cells in animals, along with root hair cells, xylem cells, and phloem cells in plants, exemplify the diverse array of specialised cells and their structures perfectly aligned with their respective functions.