Cell Specialisation

• What are specialised cells?


  Cells that have specific structures and functions to carry out specific tasks in the body.
• Plant example of specialised cells:

  Root hair, xylem and phloem
• animal example of specialised cells:

  Sperm, nerve, muscle
• Root hair cell adaptations:


  Large surface area

  Elongated shape

  No chloroplast
• What is a root hair cells function ?

  Absorb water and nutrients from soil
• What is a xylem cell’s function?


  Carry water and dissolved mineral from the roots to the leaves
• Where are xylem cells found?


  Plant stem
• What do xylem cells form?


  Long tubes
• Xylem cell’s adaptions:

  Thick walls containing lignin which supports the cell

  No internal structures
• What is the main function of root hair cells?

  To absorb water and nutrients from the soil more efficiently
• What do xylem tubes carry?

  Water and dissolved minerals from the roots to the leaves
• Why do xylem cells have thick walls containing lignin?

  To provide support to the cell
• What happens to xylem cells when their walls are sealed with lignin?

  They die and form a long tube for water and minerals to flow easily
• What internal structures do xylem cells lack?

  No nucleus, cytoplasm, vacuole, or chloroplast
• What is the function of phloem tubes?

  To carry dissolved sugars up and down the plant
• What are the two types of cells that make up phloem?

  Phloem vessel cells and companion cells
• What are sieve plates in phloem vessel cells?

  Pores in the end walls that allow dissolved sugars to move through
• How do companion cells support phloem vessel cells?

  By providing energy through mitochondria
• What is the main function of sperm cells?

  To swim to the egg
• What structure allows sperm cells to swim?

  A flagellum
• Why do sperm cells have a streamlined shape?

  To help them swim efficiently
• What do sperm cells contain to provide energy for swimming?

  Lots of mitochondria
• What is the role of digestive enzymes in sperm cells?

  To break a hole into the egg when the sperm reaches it
• What is the function of a nerve cell's long axon?

  To help transmit electrical impulses over long distances
• How does myelin affect nerve impulse transmission?

  It insulates the axon and speeds up transmission
• What are synapses in nerve cells?

  Connections that allow impulses to pass from one nerve cell to another
• What is the purpose of dendrites in nerve cells?

  To increase the surface area for connections with other nerve cells
• What allows muscle cells to contract?

  Protein fibers that change length
• What happens to protein fibers in muscle cells during contraction?

  They shorten, decreasing the length of the cell
• What do muscle cells contain to provide energy for contraction?

  Lots of mitochondria
• What are the main features of xylem and phloem cells?

  Xylem:

  • Thick walls with lignin
  • No nucleus, cytoplasm, or chloroplast
  • Forms long tubes for water transport

  
  

  Phloem:

  • Consists of phloem vessel cells and companion cells
  • Sieve plates for sugar movement
  • Companion cells provide energy
• How do the structures of sperm cells, nerve cells, and muscle cells relate to their functions?

  Sperm Cells:

  • Flagellum for swimming
  • Mitochondria for energy
  • Digestive enzymes for penetrating the egg

  
  

  Nerve Cells:

  • Long axon for impulse transmission
  • Myelin for insulation
  • Dendrites for connections

  
  

  Muscle Cells:

  • Protein fibers for contraction
  • Mitochondria for energy
• Function of muscle cell


  Contract to move bones causing movement
• How does the large surface area of a root hair cell help it perform its function?


  More water can move in/absorb
• How does the large permanent vacuole effective in a root hair cell?


  Supports cell so it can withstand amount of water