Stem cells and differentiation

• What is a stem cell?


  Undifferentiated cell that become specialised to do it’s job
• what is differentiation?


  process by which a cell becomes specialised for its job
• what are adult stem cells used for?


  to replaced damaged cells
• what are stems cells used for in plants?


  needed to make new shoots and roots throughout their lives
• Where in animals are stems cells found?

  Bone marrow
• where in plants are stem cells found?

  meristem
• How are erythrocytes specialised to function?

  carry oxygen in the blood.

  Biconcave - larger SA for gas exchange

  No nucleus - more room for haemo

  Lots of haemoglobin
• how is a neutrophil specialised to function?

  defend the body against disease.

  Lobed nucleus - so can change shape to engulf pathogens.

  lots of lysosomes - contain digestive enzymes that break down engulf particles
• how is a squamous epithelial cell specialised to function?

  line the lungs, very thin to allow efficient diffusion of oxygen.
• how is a ciliated epithelial cell specialised to function?


  lines the trachea, causes mucus to be swept away from the lungs.

  lots of cilia

  lots of mitochondria
• how is a sperm cell specialised to function?

  fertilise the egg

  flagellum - movement

  lots of mitochondria

  Acrosome - contains digestive enzymes that enable the it to penetrate the egg
• how is a palisade mesophyll cell specialised to function?

  for photosynthesis

  lots of chloroplast

  thin walls - so carbon dioxide can diffuse in easily
• how is a root hair cell specialised to function?

  increases the surface area of the cell so can absorb more water and minerals

  lots of mitochondria
• How are guard cells specialised to function?

  Controls the opening and closing of the stomata