Cell Specialisation

• A specialised cell is a cell that has a particular structure and composition of sub-cellular structures, helping them perform specific functions within the organism.
• Nerve Cells

  Adaptation: Lots of dendrites to make connections to other nerve cells
• Nerve Cells

  Adaptation: An axon carries the nerve impulse from one place to another - can be very long.
• Nerve cells

  Adaptation: Nerve cells or synapses adapted to pass the impulses to another cell or between a nerve cell or muscle in the body using special transmitter chemicals.
• Nerve cells

  Adaptation: Contain lots of mitchondria to provide energy needed to make the transmitter chemicals.
• Straited (striped) muscle cell

  Adaptation: Contain special proteins that slide over each other making the fibres contract.
• Striated (striped) muscle cells

  Adaptation: Contain many mitochondria to transfer the energy needed for the chemical reactions that take place as the cells contract & relax.
• Striated (striped) muscle cells:

  Adaptation: Can store glycogen, a chemical that can be broken down and used in cellular respriation by the mitochondria to transfer the energy needed for fibres to contract.
• Sperm cells:

  Adaptation: A long tail that whips from side to side to help sperm move through the female reproductive system.
• Sperm cells

  Adaptation: Mid-section full of mitochondria to provide energy needed to work.
• Sperm cells:

  Adaptation: Nucleus contains genetic information to be passed on to offspring.
• Root hair cells:

  Adaptation: Greatly increase the surface area available for water to move into the cell.
• Root hair cells

  Adaptation: Large permanent vacuole thats speeds up the movement of water by osmosis from the soil across the cell.
• Root hair cells

  Adaptation: Many mitochondria to transfer energy needed for the active transport of mineral ions
• Xylem cells

  Adaptation: No top or bottom walls between cells to dorm continuous hollow tubes through which water is drawn upwards towards the leaves by transpiration.
• Xylem cells

  Adaptation: Cells are essentially dead, without organelles or cytoplasm to allow free passage of water.
• Xylem cells

  Adaptation: Outer walls are thickened with lignin, strengthening the tubes which helps support the plant.
• Phloem cells

  Adaptation: Made of living cells which are supported by companion cells.
• Phloem cells

  Adaptation: Cells are joined end-to-end in the end cell walls forming tubes which allow sugars & amino acids to flow easily through.
• Phloem cells

  Adaptation: Cells also have very few sub-cellular structures to aid the flow of materials.
• Cell differentiation is an important process by which a cell changes to become specialised.
• As an organism develops, cells differentiate to form different types of cells.
• When a cell differentiates, it develops a structure and composition of sub-cellular structures which enables it to carry out a certain function.
• In an animal, most cells differentiate at an early stage of its development. Animal cells therefore lose their ability to differentiate after they have become specialised earlier in its life.
• Some cells in various locations throughout the body of an animal retain the ability to differentiate throughout the life of an animal and are called adult stem cells, which are mainly involved in replacing and repairing cells (e.g. blood and 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. These cells are found in the meristems found in shoots and root tips.