1. How is gender determined?
Chapter 3.8
How is gender determined?

2. X and Y chromosome
X and Y chromosome: all human traits are determined by 23 pairs of chromosomes.
In female, the 23rd chromosome has 2 pair of chromosomes that look the same (X and X).
In male, the 23rd chromosome has 2 pairs of chromosomes that look different (X and Y).
Female = XX
Male = XY

3. Female karyotype

4. Male karyotype

5. Gender The X and Y chromosome determine the gender of an organism.
Gender is the sex of an organism.

6. Gametes
Every sperm will have either X or Y chromosome (50% X and 50% of Y chromosome). Egg cell will have only X chromosome.

7. Results If a fertilized egg will have XX, then it’s a girl.
If a fertilized egg has XY, then it’s a boy.

8. Why do egg cells contain only one X chromosome?
As a result of meiosis, each egg cell receives only one X chromosome from the pair of X chromosomes in the female parent cell.

9. Checking concepts: Which chromosome determine gender?

10. Which parent is responsible for the gender of the offspring?

11. Fill in blanks:
1. The gender of offspring is controlled by chromosomes in the ___________________.
2. A female body cell contains two ___________________.
3. A __________________ cell can contain either an X or a Y chromosome.
4. A fertilized egg that has two X chromosomes will develop into a _______________.