Living Environment Translated Arabic 2014 | Page 48

18. Diploid cells ( have the normal number of chromosomes) are
formed during mitosis.
19. Fertilization- egg and sperm are united to form a fertilized egg
( zygote).
20. Cell division begins after fertilization.
21. A human body cell has 46 chromosomes, and a human sex cell
has 23 chromosomes.
22. DNA is a molecule that stores genetic information in all
organisms.
23. Watson and Crick, two scientists, discovered that DNA is
shaped like a doubl H[^
H