2. DNA

3. LABEL YOUR WORKSHEET

5. GENE CELL DNA CHROMOSOME NUCLEUS

7. FEMALEMALE

8. FERTILISATION

10. COPY THIS DIAGRAM

11. Sperm are made in the man’s testes Eggs are made in the woman's ovaries

12. AN EGG CELL A SPERM CELL Nucleus containing 23 chromosomes

14. This is a fertilised egg cell or zygote. The cells are dividing rapidly. Each cell contains a nucleus with 46 chromosomes in it (23 from the mother and 23 from the father).

15.  All female eggs contain an X chromosome.  But sperm can contain either an X chromosome or a Y chromosome. COPY ME

16.  XX =  XY= GIRL BOY

17. Women have 2 X chromosomes in each cell except for their sex cells. TRUE or FALSE TRUE

18. Men have 1 Y chromosome in each cell. TRUE or FALSE FALSE

19. Human egg cells contain 46 chromosomes. TRUE or FALSE FALSE

20. Every sperm has an X chromosome. Half of all sperm also have a Y chromosome. TRUE or FALSE FALSE

21. If a sperm with a Y chromosome fertilizes an egg, the embryo develops female sex organs. TRUE or FALSE FALSE

22. Your eye colour depends only on your genes, so eye colour is an inherited characteristic. TRUE or FALSE TRUE

23. You cannot influence characteristics that depend on both genetic and environmental factors. TRUE or FALSE FALSE

24. Different versions of the same gene are called alleles. TRUE or FALSE TRUE