4.1.1.4 cell differentiation

• What are cells in early development of animal and plant embryos?

  Unspecialised
• what are the unspecialised cells in animal and plant embryos called and what can they become?

  they are called stem cells and can become any type of cell
• when do cells become specialised in animals?

  early life
• what has happened to cells by the time a baby is born?

  most of the cells are specialised to carry out a particular job
• what happens to genes once the cells have specialised and why?

  some have switched off, some on as different specialised cells have different sub-cellular structures
• how can most specialised cells divide and what is a limitation to this?

  by mitosis but they can only form the same cell
• what can’t some differentiated cells do and what is an example?

  they can’t divide at all - eg. red blood cells or skin cells
• what replaces dead or damaged cells when some differentiated cells can’t?

  adult stem cells
• what is cell division restricted to in mature animals?

  just repair and replacement
• how are animal and plant cells different in terms of differentiation?

  plant cells can differentiate all throughout their lives
• where are undifferentiated cells formed in plants?

  at active regions of the stems and roots - known as meristems
• what happens in the meristems?

  mitosis takes places continuously
• can you move a plant cell from one part of the plant to another?

  yes
• when do the plant cells produced at the meristems differentiate?

  when they are in their final position in the plant
• what happens as a cell differentiates?

  it acquires different sub-cellular structures to enable it to carry out a certain function - it is now a specialised cell