X & Y Chromosomes

• Chromosomes control whether you're male or female

  • 23 pairs of chromosomes in every human body
  • 22 are matched pairs of chromosomes - control characteristics
  • 23rd pair are labeled XY or XX they decide your sex male/female
  • Males have X and Y
  • Y causes male characteristics
  • females have 2 X chromosomes
  • XX combination allows female characteristics
  • X and Y chromosomes are drawn apart in first division in meiosis
  • 50% chance of either
• Genetic diagrams shows the possible gamete combination

  • to find the probability of getting a boy or a girl - draw a genetic diagram
  • genetic diagrams are just models that are used to show all the possible genetic outcomes when you cross together