Reproduction 1. Introduction 1a. When you were conceived one sperm cell from your father joined with one egg cell from your mother.

Reproduction 1. Introduction 1b. This new cell contained the complete set of instructions for building your body.

Reproduction 1. Introduction 1c. But you are made of more than one cell. The new cell had to divide…and divide…

Reproduction 1. Introduction 1d. Just before each division that initial set of instructions was duplicated.

Reproduction 2. Parent & Daughter Cells 2a. In multi-cellular organisms growth and reproduction involve the production of new cells from existing cells. The existing cells are called parent cells The new cells are called daughter cells

Reproduction 2b. To get a daughter cell 2 things must happen: 2. Parent & Daughter Cells 2b. To get a daughter cell 2 things must happen: The parent cell must duplicate its genetic material (DNA) The parent cell must divide.

Reproduction 3. Chromosomes 3a. Genetic material (long protein chains aka DNA) is stored in a structure called a chromosome. 3b. Some parts of the DNA are used to make our physical traits. These parts are called genes.

Reproduction 3. Chromosomes 3c. A karyotype is a picture that shows the number of chromosomes in each body cell.

Reproduction 3d. Humans have 46 chromosomes or 23 pairs. Autosomal chromosomes- Pairs 1-22 Sex chromosomes- are not numbered but labeled X or Y A woman has 2 X chromosomes (XX) A male has an X & Y chromosome (XY)

Reproduction 3. Chromosomes 3e. The two chromosomes in each pair are homologous chromosomes. One comes from the mother and the other comes from the father and are almost identical.