2. Chromosomes and genes

3. Hereditary traits - Hereditary traits are passed on through generations. -Examples of traits are : your skin color, your hair, your eyes, your blood type, the shape of your nose, of your chin, a disease, etc. A hereditary trait is then a physical or a psychological characteristic that appears or not. It is passed on from the parents to the descendants. Whose nose do you have?

4. Did you know… Heredity can be complex. Sometimes one characteristic can be present in one of the parents, but won’t show in the children and vice versa. Your parents may both have brown eyes, but you can have blue eyes. Example:

5. Chromosomes All hereditary information is found in the heart of the cell, in the nucleus in the shape of sticks. These “sticks” are called chromosomes. We have 23 pairs of chromosomes. Each pair has one from the male and one from the female. The total information contained in all of the chromosomes is called the genome.

6. Check this out... Each species have different amounts of chromosomes ! The pigeon has 8 pairs! The worm has 18 pairs! The horse has 32 pairs! The butterfly has 200 pairs!

7. The genes (not the jeans...) Chromosomes have thousands of basic units that form our hereditary traits called: THE GENES They are responsible for all your characteristics (eye and hair color, your face’s shape, your skin’s color, illness’,etc.) There are 40 000 genes on the 23 chromosomes that humans have!

9. Where is DNA ? (Deoxyribonucleic acid) Your genetic code is written in the DNA The cell The nucleus Chromosomes DNA – your secret code