The role of chromosomes and hormones sex and gender Flashcards
the role of chromosomes
Chromosomes are made from DNA. Genes are short sections of DNA that determine the characteristics of a living thing. There are 46 chromosomes in the human body arranged into 23 pairs - with the last of these, the 23rd pair, determining biological sex. The chromosomal structure for females is XX, and for males XY - so named because this is how they appear when viewed under a microscope.
All normal egg cells produced by a human ovary have an X chromosome. Sperm carry an X or Y chromosome. The baby’s sex is determined by the sperm that fertilises the egg cell. The baby will be female if the fertilising sperm carries an X chromosome, or male if the sperm carries a Y chromosome.
The Y chromosome carries a gene called the ‘sex-determining region Y, or SRY for short. The SRY gene causes testes to develop in an XY embryo. These produce androgens: male sex hormones.
