Topic: Genetics Aim: Why do offspring look similar to their parents?

1. Topic: Genetics Aim: Why do offspring look similar to their parents? Do Now: 1.) List the similarities you notice amongst the family members 2.) State why they may have the same features

2. The study of how variations of traits are inherited (or passed down) through living organisms What is Genetics? Key Words gene Alleles Parent & offspring DNA Chromosomes Heredity

3. How are organisms genetically structured? Living organisms contain ___________________ inside of their nucleus which are made up of strands of ___________. This carries the hereditary information for the organism. Sections of the ____ code for a particular ________ that makes a specific trait. chromosomes DNA DNA gene

4. Who was the Father of Genetics? Gregor Mendel 1822-1884 • He was a monk and gardener who studied Math and Science • He was the 1st to study heredity in pea plants • He was 1st to trace one trait passed down through several generations

5. How did Mendel study pea plants? • He pollinated two parent pea plants and observed and recorded the traits of the new plant He referred to the traits as: Dominant- Seen often (Common) or Recessive- Not seen often (Uncommon)

6. Pea plants have fewer traits Why Pea plants to study traits? • Can grow in a large amount (quantity) • He could control the plants he desired to mate in his experiment

7. Topic: Genetics Aim: How can we examine the inherited traits found in offspring? DO NOW: 1. ) List these terms from greatest to smallest: cell, nucleus, tissue, organ, gene, DNA and chromosome. 2.)Look at the sample family. Explain why the son has freckles and mom and dad do not.

8. How do scientist today trace traits? • One or more genes found at the same point on the chromosomes represents a trait • Each person has a pair of genes for each trait • One Allele from MOM • One Allele from DAD

9. Each trait is represented by two versions called alleles Alleles • One person may have two of the same version or one of each version • The dominant allele is represented by a CAPITAL letter and the recessive is represented by a lower case letter

10. EXAMPLE: TRAITDimples E e ALLELES Dimples no dimples Dominant Recessive

11. Principles of Genetics • Traits are passed on from one generation to the next. • Traits are controlled by genes. • Organisms inherit genes in pairs (2 alleles for every trait, 1 on each strand). • Some genes are dominant, some are recessive. • Dominant genes hide recessive genes when both are inherited by an organism. • Some genes are neither dominant nor recessive (incomplete dominance)

12. What do scientists study in understanding a trait? Phenotype Is the physical appearance (___________) expressed (__________)by the organism because of their genotype feature shown

13. Genotype It is the combination of alleles (genes) in the chromosomes that determine a specific characteristic (trait) There are many types of Alleles for a trait Alleles can be _____________ or_____________ Dominant Recessive 1 mom & 1 dad

14. When the dominant allele is present the recessive trait is not seen in the phenotype Blue Eyes Brown Eyes Brown Eyes

15. How many ways can alleles be represented? Two different alleles present in the organism Heterozygous Examples: Rr Ee Tt

16. Two of the same alleles present in the organism Homozygous Examples: RR, rr EE, ee TT, tt Homozygous Dominant Homozygous Recessive

17. How do the genotype help determine the phenotype in human organisms? It is based upon the variations of alleles found on the __________________that each parent gives the offspring during the process of _______________________. chromosomes Fertilization

18. TOPIC: GeneticsAIM: What are Punnett Squares? DO NOW: Explain the difference between genotype and phenotype

19. Punnett Squares Special chart Shows probability of possible gene combinations of offspring between 2 organisms

20. What is probability? The possibility that an event may or may not happen

21. ¼ = 25% • 2/4 = 50% • 3/4 = 75% • 4/4 = 100%

22. Steps to using a Punnett Square Step # 1 – Draw Punnett square B b Step # 2 – Apply maternal and paternal genotypes B B B B b Step # 3 – Move alleles into appropriate boxes B b b b b

23. Steps to reading a Punnett Square Trait – Hair color Allele – Purple (Dom), Yellow (Rec) Step #1- Classify Genotypes B b Step # 2- Tally genotypes and phenotypes B B B B b Step # 3-Calulate ratios and percentages Homozygous Dominant Heterozygous Genotypes Phenotype 1 BB 2 Bb 1 bb B b b b b 3 Purple 1 Yellow Homozygous Recessive Heterozygous

26. Heterozygous X Heterozygous

27. Heterozygous X Homozygous recessive

28. Heterozygous X Homozygous recessive

29. Homozygous Dominant X Homozygous Recessive

30. GENDER Is the range of differences between a male and female Biologically, male and females differ in ___________which are determined by____________________ sex traits genes Whether you are a male or female depends on the presence or absence of certain chromosomes.

31. XX FEMALE Xy MALE Human cells contain 23 pairs of chromosomes for a total of 46. The sex chromosomes are the X chromosome and the Y chromosome. Chromosomes determine gender.

32. Which parent cell is responsible for your gender? XX MOM Xy DAD

33. Scientists make KARYOTYPES to look at chromosomes. A technique that involves a photograph of the chromosomes from a nucleus that are paired and arranged in size order.

34. The first 22 pairs are called autosomes and the last pair are sex chromosomes. When the chromosomes are different they are an X and a Y therefore it is a male