• We have already looked at the basic structure of animal cells and plant cells
  • It is important to note that not all cells look like this
  • A lot of cells are what we call specialised cells
  • The specialization of cells is a fundamental characteristic of living organisms.
  • Most cells, when they have finished dividing and growing, become specialised.
    • When cells are specialised:
    • they do one particular job
    • they develop a distinct shape
    • special kinds of chemical change take place in their cytoplasm.
  • Chemical reactions within the cytoplasm of specialized cells enable them to perform their specific functions.
  • This specialization of cells is sometimes referred to as the “division of labour” within the organism.
  • Mitochondria, ribosomes, and other organelles within cells may also be specialized to perform specific functions.
  • Specialized cells combine to form tissues, which are groups of cells with similar structures and functions working together.
  • Tissues, in turn, combine to form organs that perform specific functions in the body.
  • Below we will discuss various specialized cells found in plants and animals, and how they work together to enable organisms to function properly.

Bacterial Cells:

  • Smallest living cells, found in almost every environment.
  • Lack a nucleus and other membrane-bound organelles.
  • Have a cell wall made of peptidoglycan.
  • Some have flagella for movement.
  • Some have pili for attaching to surfaces.
  • Can undergo conjugation to transfer genetic material.

Ciliated Cells:

  • Found in the respiratory tract, oviducts, and other areas.
  • Have cilia, which are hair-like structures that beat in coordinated waves.
  • The movement of cilia helps to move substances across a surface, such as mucus in the respiratory tract.
  • Have a large surface area due to the presence of many cilia.

Root Hair Cells:

  • Found in plant roots and are responsible for absorbing water and minerals from the soil.
  • Have long, thin extensions called root hairs that increase the surface area for absorption.
  • Lack chloroplasts as they are not involved in photosynthesis.

Palisade Mesophyll Cells:

  • Found in the leaves of plants and are responsible for photosynthesis.
  • Have numerous chloroplasts to capture light energy.
  • Are closely packed together in parallel rows to maximize the surface area for the absorption of sunlight.


  • Specialized cells that transmit signals in the nervous system.
  • Have long extensions called axons and dendrites that help to transmit signals over long distances.
  • Have a high concentration of ion channels and neurotransmitters to facilitate signal transmission.

Red Blood Cells:

  • Carry oxygen from the lungs to the body’s tissues.
  • Lack a nucleus and other organelles, allowing more space for oxygen-carrying haemoglobin.
  • Have a unique biconcave shape that increases the surface area for oxygen exchange.
  • Are flexible and can change shape to pass through small blood vessels.
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