Inheritance of Sex

• How many pairs of chromosomes do humans contain in their normal body cells?

  23
• What is the purpose of lining up chromosomes neatly in the video?

  To see them more easily
• How many chromosome pairs contain the genes which determine inherited characteristics?

  22
• How many chromosome pairs contain the genes that determine sex?

  One
• What sex chromosomes do males have?

  X Y
• What sex chromosomes do females have?

  X X
• What chromosome is present in all of a woman's gametes?

  X chromosome
• What proportion of a man's gametes have the X chromosome?

  Half
• What proportion of a man's gametes have the Y chromosome?

  Half
• What sex chromosomes do female offspring have?

  Two X chromosomes
• What sex chromosomes do male offspring have?

  One X and one Y chromosome
• On average, what percentage of offspring are female?

  50%
• On average, what percentage of offspring are male?

  50%
• What is the ratio of female to male offspring?

  One to one
• What is stated about the probabilities of sex inheritance?

  These are just probabilities