2. A Closer Look at Conception

3. Introduction: The Genetic Package  Each of us inherits many personal characteristics from our parents.  EX: physical build, skin color, hair color & texture, eye color & shape.  Just as personal traits can be passed on, so can medical conditions.  EX: asthma, diabetes, some cancers, cystic fibrosis

4. Making A Unique Person  Each sperm & egg cell contains a different combination of genes.  Sperm: Male  Egg: Female  These cells combine during the fertilization process and produce a unique individual.

5. Chromosomes  Tiny threadlike particles located in the nucleus of every cell.  Chromosomes are what make up our genetic package  46 chromosomes = 23 pairs

6. Genes  Each chromosome contains several genes.  Genes: the unit that determine the child's inherited characteristics.  Genes makeup chromosomes as beads make up a necklace.  For every inherited characteristic, a person receives 2 copies- 1 from mom and 1 from dad.

7. Genes  If both inherited genes are the same- then the child will have that characteristic.  If they are different- the dominant gene will be expressed in the child.  Dominant: STRONGER gene  Recessive: WEAKER gene

8. Let’s Understand Genes (eye color) B= Brown Dominant b= Blue recessive Dad (Bb)Mom (Bb) Child 1 Child 2 Child 3 Child 4 (BB) (Bb) (Bb) (bb)

9. Determining Sex  The sex of a child is determined at conception.  Every egg cell contains an X chromosome.  Each sperm cell will contain either an X or a Y chromosome.  The sex of the child is determined by the chromosome carried by the sperm that fertilizes the egg.  XX= baby girl  XY= baby boy

10. Multiple Births  Identical Twins: 1 egg divides in half soon after fertilization. Each half grows and divides. 1 Zygote (the egg and sperm combined) becomes 2.  Fraternal Twins: 2 eggs are released and both become fertilized Identical Fraternal

11. Infertility  Infertile: inability to conceive a child.  There are many causes of infertility in both men and women.  Options for Infertile Couples:  Adoption- a couple legally takes on all responsibilities and rights for raising, loving, and caring for a child in need of a permanent home.  Artificial Insemination- doctor injects sperm into the uterus. Sperm may be the husband’s or from a donor.

12. Infertility  More Options for Infertile Couples:  In Vitro Fertilization- Doctor combines a mature ovum from the woman with sperm from her husband. If the ovum becomes fertilized then the doctor places it in the uterus.  Ovum Transfer- Similar to In Vitro, except that the ovum is donated by another woman. It is fertilized in the laboratory and placed in the uterus.  Surrogate Mother- A surrogate mother is a substitute woman who becomes pregnant to have a baby for another woman.

13. Videos about Infertility  In Vitro Fertilization: http://video.nationalgeographic.com/video/ivf-sci http://video.nationalgeographic.com/video/ivf-sci  Ovum Transfer: https://www.youtube.com/watch?v=pGeIYV1HoP4 https://www.youtube.com/watch?v=pGeIYV1HoP4  Artificial Insemination: https://www.youtube.com/watch?v=S6FmkzOf9ao https://www.youtube.com/watch?v=S6FmkzOf9ao

14. Let’s Review 1.List 3 traits that are inherited. 2.Explain how dominant and recessive genes work. 3.How is the sex of a baby determined? 4.What is the difference between identical twins and fraternal twins? 5.What are some disadvantages of fertility drugs?