X and Y chromosomes


X and Y chromosomes:

Your chromosomes control whether you are Male or Female.

There are 23 pairs of chromosomes in every human body cell. Of these 22 are matched pairs of chromosomes that just control characteristics. The 23rd pair are labelled XY or **. They're the two chromosomes that decide your sex - whether you turn out male of female.

Males have an X and Y chromosome: XY - The Y chromosome causes male characteristics.

Females have two X chromosomes: ** - The ** combination allows female characteristics.

When making sperm, the X and Y chromosomes are drawn apart in the first division in meiosis. There is a 50% chance each sperm cell gets an X-chromosome and a 50% chance it gets a Y-chromosome.

A similar thing happens when making eggs. But the orginal cell has two X-chromosomes, so all the eggs have one


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