Sex Chromosomes Flashcards
What are the female sex chromosomes?
They are identical; they are both X chromosomes
What are the male sex chromosomes?
They are different; there is an X & a Y chromosome (the Y chromosome is much shorter than the X chromosome.
What is the differences between the sperm and the egg?
Half the sperm carries an X chromosome and half a Y chromosome. Whereas all the eggs carry X chromosomes.
How a boy or a girl is produced?
If an X sperm fertilises the egg, a girl is produced.
If a Y sperm fertilises the egg, a boy is produced.
How is the sex of an individual determined?
It is determined by a gene on the Y chromosome called the sex-determining region Y (SRY) gene
What happens if the SRY gene isn’t present?
There will be two X chromosomes present and the embryo will develop into a female.
What happens if the SRY gene is present?
Then a Y chromosome and an X chromosome are present and testes begin to develop
What happens 6 weeks into fertilisation if the SRY gene was present?
The testes that developed start producing a hormone called androgen. Specialised receptors in the developing embryo detect the androgen and male reproductive organs begin to grow.
What happens when the Y Chromosome is present but the androgen isn’t detected?
The embryo develops female sex organs apart from the uterus which means the baby has a female body but is infertile.
