Specialised cells

• What are erythrocytes and how are they specialised?


  Red blood cells - carry oxygen from lungs to respiratory cells , they derive from stem bone marrow

  • Small with a large surface area to volume
  • Bioconcave shape - Oxygen can diffuse across the membrane and reach all regions inside
  • Flexible - developed a cytoskeleton which allows change of shape in order to travel through narrow capillaries
  • Most organelles are lost at differentiation which leaves more space for haemoglobin
• Haemoglobin is synthesised in immature red blood cells when they still have nucleus, ribosomes and RER
• What are Neutrophills and how are they specialised?

  • White blood cells - ingest invading pathogens, make up 50% of white blood cells in your body
  • larger - they are twice the size of red blood cells
  • Contain a multilobed nucleus
  • Attracted to and travel towards infection sites by chemotaxis
• How are sperm cells specialised?

  • Many mitochondria - carry out aerobic respiration
  • ATP energy - for tail to move and propel cell forwards towards ovum
  • Small but long and thin - move easily
  • Once reached ovum enzymes are released from the actosome, the enzymes digest outer protectivelayer and allows sperm head to enter
  • Head - contains haploid gamete nucleus, very little cytoplasm
• What are epithelial cells 


  Epithelium is a lining tissue found on the outside of your body and inside

  Such as alevoli, capillaries, lining of intestines
• How are epithelial cells specialised?


  Squamous epithelial cells are a flattened shape

  Many cells in the epithelium have cilia
• How are palisade cells specialised?

  • Long and cylindrical - pack together closel, little space for air to circulate carbon dioxide in air spaces is diffused into cells
  • Large vacuole
  • Chloroplast positioned closer to edge of the cell to reduce diffusion distance of carbon dioxide
  • many chloroplast
  • contain cytoskeleton threads and motor proteins to move the chloroplasts nearer to the surface when light intensity is low and further down when it is high
• How are guard cells specialised?

  • Light energy is used to produce ATP
  • ATP actively transports potassium ions from epidermal cells into guard cells (lower water potential)
  • Water enters guard cells from neighbouring epidermal cells by osmosis
  • Guard cells swell
  • Stomata open - air can enteR spaces within layers of cells beneath palisade cells
  • Gaseous exchange occurs
  • Oxygen produced can diffuse out through stomata
• How are root hair cells specialised ?

  • Hair like projection - increase surface area for absorption of water and mineral ions
  • Special carrier proteins in plasma membrane for active transport
  • Produce ATP for active transport