1. Generation to Generation
Chapter 20.2
Generation to Generation

2. Chromosomes Chromosomes Tiny structures within the center of cells
Carry information about hereditary traits
DNA – foundation of chromosomes
Deoxyribonucleic Acid

3. Genes Genes Segments of DNA molecules Contributed from both parents
Makes you unique
Genes can be Dominant or Recessive

4. Genes and Gender Human body cells contain 46 chromosomes
23 from sperm and 23 from ova
Zygote has 46
Each time the zygote divides each cell keeps the 46 chromosomes

5. Genes and Gender Ovum can only contain an X Chromosome
Sperm can contain either X or Y Chromosomes
XX = girl
XY = boy

6. Genetic Disorders Abnormalities in the genetic code Sickle Cell Anemia
Phenylketonuria (PKU)
Tay-Sachs Disease
Cystic Fibrosis
Down Syndrome

7. Identifying Genetic Disorders
Amniocentesis – a sample of the amniotic fluid is tested
Ultrasound – sound waves create an image of the fetus
Chorionic Villi Sampling – a piece of tissue is removed from the placenta for testing