1. A Closer Look at Conception
The Developing Child
Chapter 5 Section 2

2. Introduction: The Genetic Package
Each of us inherit 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.

3. Chromosomes
Tiny threadlike particles located in the nucleus of every cell.
46 chromosomes = 23 pairs

4. 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.

5. 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.
Dominant- stronger gene.
Recessive- weaker gene.

6. Genes Ex: B= Brown Dominant, b= Blue recessive. Dad (Bb) Mom (Bb)
Child 1 Child 2 Child Child 4
(BB) (Bb) (Bb) (bb)

7. Making A Unique Person
Each sperm & egg cell contains a different combination of genes.
These cells combine during the fertilization process and produce a unique individual.

8. 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

9. Multiple Births
Identical Twins= 1 egg divides in half soon after fertilization. Each half grows and divides. 1 Zygote becomes 2.
Fraternal Twins= 2 eggs are released and both becomes fertilized

10. 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.

11. Infertility 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.

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

13. Assignment
Heredity in the Works Worksheet