Gametes
Female sex cells are called ova. They are adapted for their job because they contain a haploid nucleus that because diploid with a sperm cell. It also has lots of cytoplasm which contains nutrients and its jelly coat turns to a structure that stops other sperm cells entering after fertilisation.
- A fertilised ovum is called a zygote. You will have to know this in I/GCSE Biology
Sperm cells are either male or female. They have a tail for swimming, an acrosome containing digestive enzymes to break the jelly coat of an egg cell and they have many mitochondria in their middle section to provide energy for swimming. They also have a haploid nucleus that becomes diploid with an egg cell.
Sex Chromosomes
The genotype for a male is XY and the genotype for a female is **. Sperm are haploid so will contain either an X or Y chromosome, making some female and some male. All ova are female because they all contain X chromosomes, despite being haploid. The Y chromosome is slightly shorter than the X chromosome on its horizontal axis and this allows male characteristics to develop. This means there is a 50%, all of the time, of having a male child over a female child.
Reference: https://previews.123rf.com/images/luckysoul/luckysoul1910/luckysoul191000002/134589632-female-reproductive-cell-oocytes-male-sex-cell-sperm-cell-structure-reproduction-in-humans-and-anima.jpg
https://www.standardofcare.com/artimgs/2122.png
Drafted by Catrina (Biology)