stem cells

• how are stem cells used in medicine?

  to replace damaged/diseased cells
• what is the purpose of embryonic stem cells?

  they divide very quickly to make the foetus grow, they can differentiate into any human cell
• body cells normally have 2 copies of each chromosome, what type of cell is this?

  diploid cell, 46 chromosomes
• where do all the different types of cell found in a human come from?

  they come from a few cells in the early embryo
• what is the difference between embryonic and adult stem cells?

  adult stem cells aren’t as versatile, they can’t produce any cell type, only certain ones
• what is the difference between embryonic stem cells and meristem cells?

  they both produce any cell type but unlike human stem cells, meristems can divide and differentiate into any cell for as long as the plant lives
• what do unspecialised cells in plants go on to form?

  specialised tissues like xylem and phloem
• where are stem cells extracted from to be used in medicine?

  scientists have experimented with extracting stem cells from very early human embryos and growing them
• why does using embryonic cells raise ethical issues?

  some people argue that human embryos shouldn’t be used for experiments because each one is a potential life
• where is the zone of cell division?

  this zone is near the tip of a root.
• where is the zone of elongation?

  this zone is further up the root, next to the zone of cell division.
• where is the zone of differentiation?

  this zone is even further up the root, next to the zone of elongation.
• in human adults, where are stem cells found?

  Bone marrow
• where are plant stem cells found?

  meristem tissue