1. HEREDITY Chapter 5

2. Heredity- The passing of traits from parent to offspring Genes on chromosomes control the traits that show up in an organism The different forms of a trait that a gene may have are alleles During meiosis a pair of chromosomes separates and the allelles move into separate SEX CELLS. Each sex cell now contains ONE allele for each trait Genetics- The study of how traits are inherited

3. Name some traits you have inherited from your mom, Dad, Grandma, Grandpa…etc

4. GREGOR MENDEL The father of genetics Mendel was the first to use mathematical probability to explain heredity and to trace one trait for several generations.

5. Hybrid- receive different genetic information for a trait from each parent DOMINANT ALLELE Covers up or dominates the other trait RECESSIVE ALLELE The trait seems to disappear

6. PUNNETT SQUARE- can help you predict what an offspring will look like Uppercase letters stand for dominant alleles Lowercase letters stand for recessive alleles

9. Genotype- the genetic make-up of an organism Homozygous- an organism with two alleles for one trait that are the same (TT) Heterozygous- an organism with two alleles for one trait that are different (Tt) Phenotype- The way an organism looks or behaves as a result of its genotype

10. How do heredity and genetics explain why people are different?

11. Incomplete dominance Neither allele for a trait is dominant The phenotype produced is intermediate between the two homozygous parents

12. Multiple alleles More then two alleles that control a trait are called multiple alleles Traits controlled by multiple alleles produce more then three phenotypes

13. Polygenic inheritance A group of gene pairs acts together to produce a trait, which creates more variety in phenotypes Many human traits are controlled by polygenic inheritance, such as hair and eye color

14. Polygenic traits

15. MUTATIONS- genes that are altered or copied incorrectly A mutation can be harmful, beneficial, or have no effect chromosome disorders- caused by more or fewer chromosomes then normal Down’s syndrome- caused by an extra copy of chromosome 21

16. Examples of mutations

17. Recessive genetic disorders Both parents have a recessive allele responsible for the disorder and pass it on to their child Because the parents are heterozygous, they do not show any symptoms Cystic fibrosis is a homozygous recessive disorder

19. SEX DETERMINATION Chromosomes that determine the sex of an organism are XX in females and XY in males Females produse eggs with an X chromosome only, males produce sperm with either an X or a Y

20. Sex Linked Disorders An allele inherited on an X or Y chromosome is a sex-linked gene. Color blindness is a sex linked disorder caused by a recessive allele on the X chromosome. A Pedigree follows a trait through generations of a family

21. How does environment affect your hereditary traits?

22. ADVANCES IN GENETICS Genetic engineering- changing the arrangement of DNA that makes up a gene Recombinant DNA-insertion of a useful segment of DNA into bacterium - insulin is made by genetically engineered organisms Gene therapy- a normal allele is placed into the virus which delivers the normal allele when it effects its target cell. Can be used to control cystic fibrosis or other genetic disorders. Genetically engineered plants- created by inserting the genes that produce the desired traits in one plant into another.

23. Explain what is happening in these cartoons.

25. Genetically engineered plants and food

26. Recombinant DNA